    Internet Engineering Task Force (IETF)                          M. Sweet
    Request for Comments: 8011                                    Apple Inc.
    Obsoletes: 2911, 3381, 3382                                  I. McDonald
    Category: Standards Track                               High North, Inc.
    ISSN: 2070-1721                                             January 2017

              Internet Printing Protocol/1.1: Model and Semantics

    Abstract

       The Internet Printing Protocol (IPP) is an application-level protocol
       for distributed printing using Internet tools and technologies.  This
       document describes a simplified model consisting of abstract objects,
       attributes, and operations that is independent of encoding and
       transport.  The model consists of several objects, including Printers
       and Jobs.  Jobs optionally support multiple Documents.

       IPP semantics allow End Users and Operators to query Printer
       capabilities; submit Print Jobs; inquire about the status of Print
       Jobs and Printers; and cancel, hold, and release Print Jobs.  IPP
       semantics also allow Operators to pause and resume Jobs and Printers.

       Security, internationalization, and directory issues are also
       addressed by the model and semantics.  The IPP message encoding and
       transport are described in "Internet Printing Protocol/1.1: Encoding
       and Transport" (RFC 8010).

       This document obsoletes RFCs 2911, 3381, and 3382.

    Status of This Memo

       This is an Internet Standards Track document.

       This document is a product of the Internet Engineering Task Force
       (IETF).  It represents the consensus of the IETF community.  It has
       received public review and has been approved for publication by the
       Internet Engineering Steering Group (IESG).  Further information on
       Internet Standards is available in Section 2 of RFC 7841.

       Information about the current status of this document, any errata,
       and how to provide feedback on it may be obtained at
       http://www.rfc-editor.org/info/rfc8011.

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    Copyright Notice

       Copyright (c) 2017 IETF Trust and the persons identified as the
       document authors.  All rights reserved.

       This document is subject to BCP 78 and the IETF Trust's Legal
       Provisions Relating to IETF Documents
       (http://trustee.ietf.org/license-info) in effect on the date of
       publication of this document.  Please review these documents
       carefully, as they describe your rights and restrictions with respect
       to this document.  Code Components extracted from this document must
       include Simplified BSD License text as described in Section 4.e of
       the Trust Legal Provisions and are provided without warranty as
       described in the Simplified BSD License.

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    RFC 8011              IPP/1.1: Model and Semantics          January 2017

    Table of Contents

       1. Introduction ....................................................9
          1.1. Simplified Printing Model .................................12
       2. Conventions Used in This Document ..............................15
          2.1. Requirements Language .....................................15
          2.2. Printing Terminology ......................................15
          2.3. Model Terminology .........................................16
               2.3.1. Administrator ......................................16
               2.3.2. Attributes .........................................16
                      2.3.2.1. Attribute Group Name ......................16
                      2.3.2.2. Attribute Name ............................16
                      2.3.2.3. Attribute Syntax ..........................16
                      2.3.2.4. Attribute Value ...........................17
               2.3.3. End User ...........................................17
               2.3.4. Impression .........................................17
               2.3.5. Input Page .........................................17
               2.3.6. Job Creation Operation .............................17
               2.3.7. Keyword ............................................17
               2.3.8. Media Sheet ........................................18
               2.3.9. Operator ...........................................18
               2.3.10. Set ...............................................18
               2.3.11. Support of Attributes .............................18
               2.3.12. Terminating State .................................21
          2.4. Abbreviations .............................................21
       3. IPP Objects ....................................................22
          3.1. Printer Object ............................................22
          3.2. Job Object ................................................25
          3.3. Object Relationships ......................................25
          3.4. Object Identity ...........................................26
       4. IPP Operations .................................................29
          4.1. Common Semantics ..........................................30
               4.1.1. Required Parameters ................................30
               4.1.2. Operation IDs and Request IDs ......................31
               4.1.3. Attributes .........................................31
               4.1.4. Character Set and Natural Language
                      Operation Attributes ...............................33
                      4.1.4.1. Request Operation Attributes ..............34
                      4.1.4.2. Response Operation Attributes .............38
               4.1.5. Operation Targets ..................................39
               4.1.6. Operation Response Status-Code Values and
                      Status Messages ....................................41
                      4.1.6.1. "status-code" (type2 enum) ................41
                      4.1.6.2. "status-message" (text(255)) ..............42
                      4.1.6.3. "detailed-status-message" (text(MAX)) .....43
                      4.1.6.4. "document-access-error" (text(MAX)) .......43

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               4.1.7. Unsupported Attributes .............................44
               4.1.8. Versions ...........................................45
               4.1.9. Job Creation Operations ............................48
          4.2. Printer Operations ........................................50
               4.2.1. Print-Job Operation ................................51
                      4.2.1.1. Print-Job Request .........................51
                      4.2.1.2. Print-Job Response ........................56
               4.2.2. Print-URI Operation ................................58
               4.2.3. Validate-Job Operation .............................59
               4.2.4. Create-Job Operation ...............................59
               4.2.5. Get-Printer-Attributes Operation ...................60
                      4.2.5.1. Get-Printer-Attributes Request ............61
                      4.2.5.2. Get-Printer-Attributes Response ...........63
               4.2.6. Get-Jobs Operation .................................64
                      4.2.6.1. Get-Jobs Request ..........................65
                      4.2.6.2. Get-Jobs Response .........................66
               4.2.7. Pause-Printer Operation ............................68
                      4.2.7.1. Pause-Printer Request .....................71
                      4.2.7.2. Pause-Printer Response ....................71
               4.2.8. Resume-Printer Operation ...........................72
               4.2.9. Purge-Jobs Operation ...............................73
          4.3. Job Operations ............................................73
               4.3.1. Send-Document Operation ............................74
                      4.3.1.1. Send-Document Request .....................75
                      4.3.1.2. Send-Document Response ....................77
               4.3.2. Send-URI Operation .................................78
               4.3.3. Cancel-Job Operation ...............................78
                      4.3.3.1. Cancel-Job Request ........................80
                      4.3.3.2. Cancel-Job Response .......................81
               4.3.4. Get-Job-Attributes Operation .......................81
                      4.3.4.1. Get-Job-Attributes Request ................82
                      4.3.4.2. Get-Job-Attributes Response ...............83
               4.3.5. Hold-Job Operation .................................84
                      4.3.5.1. Hold-Job Request ..........................86
                      4.3.5.2. Hold-Job Response .........................87
               4.3.6. Release-Job Operation ..............................87
               4.3.7. Restart-Job Operation ..............................89
                      4.3.7.1. Restart-Job Request .......................91
                      4.3.7.2. Restart-Job Response ......................92
       5. Object Attributes ..............................................92
          5.1. Attribute Syntaxes ........................................92
               5.1.1. Out-of-Band Values - 'unknown',
                      'unsupported', and 'no-value' ......................93
               5.1.2. 'text' .............................................93
                      5.1.2.1. 'textWithoutLanguage' .....................94
                      5.1.2.2. 'textWithLanguage' ........................94

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               5.1.3. 'name' .............................................95
                      5.1.3.1. 'nameWithoutLanguage' .....................96
                      5.1.3.2. 'nameWithLanguage' ........................96
                      5.1.3.3. Matching 'name' Attribute Values ..........97
               5.1.4. 'keyword' ..........................................98
               5.1.5. 'enum' .............................................99
               5.1.6. 'uri' .............................................100
               5.1.7. 'uriScheme' .......................................100
               5.1.8. 'charset' .........................................101
               5.1.9. 'naturalLanguage' .................................102
               5.1.10. 'mimeMediaType' ..................................102
                      5.1.10.1. 'application/octet-stream' -
                                Auto-Sensing the Document Format ........103
               5.1.11. 'octetString' ....................................104
               5.1.12. 'boolean' ........................................104
               5.1.13. 'integer' ........................................104
               5.1.14. 'rangeOfInteger' .................................105
               5.1.15. 'dateTime' .......................................105
               5.1.16. 'resolution' .....................................105
               5.1.17. 'collection' .....................................105
               5.1.18. '1setOf X' .......................................106
          5.2. Job Template Attributes ..................................106
               5.2.1. job-priority (integer(1:100)) .....................109
               5.2.2. job-hold-until (type2 keyword | name(MAX)) ........111
               5.2.3. job-sheets (type2 keyword | name(MAX)) ............112
               5.2.4. multiple-document-handling (type2 keyword) ........113
               5.2.5. copies (integer(1:MAX)) ...........................115
               5.2.6. finishings (1setOf type2 enum) ....................115
               5.2.7. page-ranges (1setOf rangeOfInteger(1:MAX)) ........118
               5.2.8. sides (type2 keyword) .............................119
               5.2.9. number-up (integer(1:MAX)) ........................120
               5.2.10. orientation-requested (type2 enum) ...............120
               5.2.11. media (type2 keyword | name(MAX)) ................123
               5.2.12. printer-resolution (resolution) ..................124
               5.2.13. print-quality (type2 enum) .......................124
          5.3. Job Description and Status Attributes ....................124
               5.3.1. job-id (integer(1:MAX)) ...........................126
               5.3.2. job-uri (uri) .....................................126
               5.3.3. job-printer-uri (uri) .............................127
               5.3.4. job-more-info (uri) ...............................127
               5.3.5. job-name (name(MAX)) ..............................127
               5.3.6. job-originating-user-name (name(MAX)) .............128
               5.3.7. job-state (type1 enum) ............................128
                      5.3.7.1. Forwarding Servers .......................132
                      5.3.7.2. Partitioning of Job States ...............132
               5.3.8. job-state-reasons (1setOf type2 keyword) ..........133
               5.3.9. job-state-message (text(MAX)) .....................138
               5.3.10. job-detailed-status-messages (1setOf text(MAX)) ..139

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               5.3.11. job-document-access-errors (1setOf text(MAX)) ....139
               5.3.12. number-of-documents (integer(0:MAX)) .............139
               5.3.13. output-device-assigned (name(127)) ...............139
               5.3.14. Event Time Job Status Attributes .................140
                      5.3.14.1. time-at-creation (integer(MIN:MAX)) .....140
                      5.3.14.2. time-at-processing (integer(MIN:MAX)) ...141
                      5.3.14.3. time-at-completed (integer(MIN:MAX)) ....141
                      5.3.14.4. job-printer-up-time (integer(1:MAX)) ....141
                      5.3.14.5. date-time-at-creation
                                (dateTime|unknown) ......................141
                      5.3.14.6. date-time-at-processing
                                (dateTime|unknown|no-value) .............141
                      5.3.14.7. date-time-at-completed
                                (dateTime|unknown|no-value) .............141
               5.3.15. number-of-intervening-jobs (integer(0:MAX)) ......142
               5.3.16. job-message-from-operator (text(127)) ............142
               5.3.17. Job Size Attributes ..............................142
                      5.3.17.1. job-k-octets (integer(0:MAX)) ...........142
                      5.3.17.2. job-impressions (integer(0:MAX)) ........143
                      5.3.17.3. job-media-sheets (integer(1:MAX)) .......143
               5.3.18. Job Progress Attributes ..........................144
                      5.3.18.1. job-k-octets-processed
                                (integer(0:MAX)) ........................144
                      5.3.18.2. job-impressions-completed
                                (integer(0:MAX)) ........................144
                      5.3.18.3. job-media-sheets-completed
                                (integer(0:MAX)) ........................144
               5.3.19. attributes-charset (charset) .....................144
               5.3.20. attributes-natural-language (naturalLanguage) ....145
          5.4. Printer Description and Status Attributes ................145
               5.4.1. printer-uri-supported (1setOf uri) ................147
               5.4.2. uri-authentication-supported (1setOf type2
                      keyword) ..........................................148
               5.4.3. uri-security-supported (1setOf type2 keyword) .....149
               5.4.4. printer-name (name(127)) ..........................150
               5.4.5. printer-location (text(127)) ......................150
               5.4.6. printer-info (text(127)) ..........................151
               5.4.7. printer-more-info (uri) ...........................151
               5.4.8. printer-driver-installer (uri) ....................151
               5.4.9. printer-make-and-model (text(127)) ................151
               5.4.10. printer-more-info-manufacturer (uri) .............151
               5.4.11. printer-state (type1 enum) .......................152
               5.4.12. printer-state-reasons (1setOf type2 keyword) .....152
               5.4.13. printer-state-message (text(MAX)) ................157
               5.4.14. ipp-versions-supported (1setOf type2 keyword) ....157
               5.4.15. operations-supported (1setOf type2 enum) .........157

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               5.4.16. multiple-document-jobs-supported (boolean) .......159
               5.4.17. charset-configured (charset) .....................159
               5.4.18. charset-supported (1setOf charset) ...............159
               5.4.19. natural-language-configured (naturalLanguage) ....160
               5.4.20. generated-natural-language-supported
                       (1setOf naturalLanguage) .........................160
               5.4.21. document-format-default (mimeMediaType) ..........160
               5.4.22. document-format-supported (1setOf
                       mimeMediaType) ...................................161
               5.4.23. printer-is-accepting-jobs (boolean) ..............161
               5.4.24. queued-job-count (integer(0:MAX)) ................161
               5.4.25. printer-message-from-operator (text(127)) ........161
               5.4.26. color-supported (boolean) ........................161
               5.4.27. reference-uri-schemes-supported (1setOf
                       uriScheme) .......................................162
               5.4.28. pdl-override-supported (type2 keyword) ...........162
               5.4.29. printer-up-time (integer(1:MAX)) .................162
               5.4.30. printer-current-time (dateTime|unknown) ..........163
               5.4.31. multiple-operation-time-out (integer(1:MAX)) .....164
               5.4.32. compression-supported (1setOf type2 keyword) .....164
               5.4.33. job-k-octets-supported (rangeOfInteger(0:MAX)) ...165
               5.4.34. job-impressions-supported
                       (rangeOfInteger(0:MAX)) ..........................165
               5.4.35. job-media-sheets-supported
                       (rangeOfInteger(1:MAX)) ..........................165
               5.4.36. pages-per-minute (integer(0:MAX)) ................165
               5.4.37. pages-per-minute-color (integer(0:MAX)) ..........165
       6. Conformance ...................................................166
          6.1. Client Conformance Requirements ..........................166
          6.2. IPP Object Conformance Requirements ......................168
               6.2.1. Objects ...........................................168
               6.2.2. Operations ........................................168
               6.2.3. IPP Object Attributes .............................170
               6.2.4. Versions ..........................................170
               6.2.5. Extensions ........................................171
               6.2.6. Attribute Syntaxes ................................171
               6.2.7. Security ..........................................172
          6.3. Charset and Natural Language Requirements ................172
       7. IANA Considerations ...........................................173
          7.1. Object Extensions ........................................174
          7.2. Attribute Extensibility ..................................174
          7.3. Keyword Extensibility ....................................175
          7.4. Enum Extensibility .......................................176
          7.5. Attribute Group Extensibility ............................176
          7.6. Out-of-Band Attribute Value Extensibility ................176
          7.7. Attribute Syntax Extensibility ...........................177
          7.8. Operation Extensibility ..................................177
          7.9. Status-Code Extensibility ................................178

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       8. Internationalization Considerations ...........................179
       9. Security Considerations .......................................183
          9.1. Security Scenarios .......................................184
               9.1.1. Client and Server in the Same Security Domain .....184
               9.1.2. Client and Server in Different Security Domains ...184
               9.1.3. Print by Reference ................................184
          9.2. URIs in Operation, Job, and Printer Attributes ...........185
          9.3. URIs for Each Authentication Mechanism ...................185
          9.4. Restricted Queries .......................................186
          9.5. Operations Performed by Operators and Administrators .....186
          9.6. Queries on Jobs Submitted Using Non-IPP Protocols ........186
       10. Changes since RFC 2911 .......................................187
       11. References ...................................................188
          11.1. Normative References ....................................188
          11.2. Informative References ..................................194
       Appendix A. Formats for IPP Registration Proposals ...............197
         A.1. Attribute Registration ....................................197
         A.2. type2 'keyword' Attribute Value Registration ..............198
         A.3. type2 'enum' Attribute Value Registration .................198
         A.4. Operation Registration ....................................199
         A.5. Status-Code Registration ..................................199
       Appendix B. Status-Code Values and Suggested Status-Code
                   Messages .............................................200
         B.1. Status-Code Values ........................................201
           B.1.1. Informational .........................................201
           B.1.2. Successful Status-Code Values .........................201
             B.1.2.1. successful-ok (0x0000) ............................201
             B.1.2.2. successful-ok-ignored-or-substituted-attributes
                      (0x0001) ..........................................202
             B.1.2.3. successful-ok-conflicting-attributes (0x0002) .....202
           B.1.3. Redirection Status-Code Values ........................202
           B.1.4. Client Error Status-Code Values .......................202
             B.1.4.1. client-error-bad-request (0x0400) .................203
             B.1.4.2. client-error-forbidden (0x0401) ...................203
             B.1.4.3. client-error-not-authenticated (0x0402) ...........203
             B.1.4.4. client-error-not-authorized (0x0403) ..............203
             B.1.4.5. client-error-not-possible (0x0404) ................203
             B.1.4.6. client-error-timeout (0x0405) .....................204
             B.1.4.7. client-error-not-found (0x0406) ...................204
             B.1.4.8. client-error-gone (0x0407) ........................204
             B.1.4.9. client-error-request-entity-too-large (0x0408) ....205
             B.1.4.10. client-error-request-value-too-long (0x0409) .....205
             B.1.4.11. client-error-document-format-not-supported
                       (0x040a) .........................................205
             B.1.4.12. client-error-attributes-or-values-not-supported
                       (0x040b) .........................................206
             B.1.4.13. client-error-uri-scheme-not-supported (0x040c) ...206
             B.1.4.14. client-error-charset-not-supported (0x040d) ......206

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             B.1.4.15. client-error-conflicting-attributes (0x040e) .....207
             B.1.4.16. client-error-compression-not-supported (0x040f) ..207
             B.1.4.17. client-error-compression-error (0x0410) ..........207
             B.1.4.18. client-error-document-format-error (0x0411) ......207
             B.1.4.19. client-error-document-access-error (0x0412) ......207
           B.1.5. Server Error Status-Code Values .......................208
             B.1.5.1. server-error-internal-error (0x0500) ..............208
             B.1.5.2. server-error-operation-not-supported (0x0501) .....208
             B.1.5.3. server-error-service-unavailable (0x0502) .........208
             B.1.5.4. server-error-version-not-supported (0x0503) .......209
             B.1.5.5. server-error-device-error (0x0504) ................209
             B.1.5.6. server-error-temporary-error (0x0505) .............210
             B.1.5.7. server-error-not-accepting-jobs (0x0506) ..........210
             B.1.5.8. server-error-busy (0x0507) ........................210
             B.1.5.9. server-error-job-canceled (0x0508) ................210
             B.1.5.10. server-error-multiple-document-jobs-not-supported
                       (0x0509) .........................................210
         B.2. Status-Code Values for IPP Operations .....................211
       Appendix C. Processing IPP Attributes ............................213
         C.1. Fidelity ..................................................213
         C.2. Page Description Language (PDL) Override ..................215
         C.3. Using Job Template Attributes during Document Processing ..217
       Appendix D. Generic Directory Schema .............................218
       Acknowledgements .................................................221
       Authors' Addresses ...............................................221

    1.  Introduction

       The Internet Printing Protocol (IPP) is an application-level protocol
       for distributed printing using Internet tools and technologies.  IPP
       version 1.1 (IPP/1.1) focuses primarily on End User functionality
       with a few administrative operations included.  IPP versions 2.0,
       2.1, and 2.2 provide many new operations and are defined separately.

       This document is just one of a suite of documents that fully define
       IPP.  The full set of IETF IPP documents includes:

          Design Goals for an Internet Printing Protocol [RFC2567]

          Rationale for the Structure of the Model and Protocol for the
          Internet Printing Protocol [RFC2568]

          Internet Printing Protocol/1.1: Model and Semantics (this
          document)

          Internet Printing Protocol/1.1: Encoding and Transport [RFC8010]

          Internet Printing Protocol/1.1: Implementor's Guide [RFC3196]

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    RFC 8011              IPP/1.1: Model and Semantics          January 2017

          Internet Printing Protocol/1.1: IPP URL Scheme [RFC3510]

          Internet Printing Protocol (IPP) over HTTPS Transport Binding and
          the 'ipps' URI Scheme [RFC7472]

          Internet Printing Protocol (IPP): Requirements for Job, Printer,
          and Device Administrative Operations [RFC3239]

          Internet Printing Protocol (IPP): Job and Printer Set Operations
          [RFC3380]

          Internet Printing Protocol (IPP): Job and Printer Administrative
          Operations [RFC3998]

          Internet Printing Protocol (IPP): Requirements for IPP
          Notifications [RFC3997]

          Internet Printing Protocol (IPP): Event Notifications and
          Subscriptions [RFC3995]

          Internet Printing Protocol (IPP): The 'ippget' Delivery Method for
          Event Notifications [RFC3996]

          Mapping between LPD and IPP Protocols [RFC2569]

       Anyone reading these documents for the first time is strongly
       encouraged to read the IPP documents in the above order.  Additional
       IPP specifications have been published by the IEEE-ISTO Printer
       Working Group's IPP Workgroup [PWG-IPP-WG].  The following standards
       are highly recommended reading:

          PWG Media Standardized Names 2.0 (MSN2) [PWG5101.1]

          IPP Finishings 2.0 (FIN) [PWG5100.1]

          Internet Printing Protocol (IPP): "output-bin" attribute extension
          [PWG5100.2]

          Internet Printing Protocol (IPP): Production Printing Attributes -
          Set 1 [PWG5100.3] (for "media-col" Job Template attribute)

          Standard for The Internet Printing Protocol (IPP): Document Object
          [PWG5100.5]

          Standard for The Internet Printing Protocol (IPP): Page Overrides
          [PWG5100.6]

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          Standard for The Internet Printing Protocol (IPP): Job Extensions
          [PWG5100.7]

          Standard for Internet Printing Protocol (IPP): "-actual"
          attributes [PWG5100.8]

          Internet Printing Protocol (IPP): Printer State Extensions v1.0
          [PWG5100.9]

          Internet Printing Protocol (IPP): Job and Printer Extensions -
          Set 2 (JPS2) [PWG5100.11]

          IPP Version 2.0, 2.1, and 2.2 [PWG5100.12]

          IPP: Job and Printer Extensions - Set 3 (JPS3) [PWG5100.13]

          IPP Everywhere [PWG5100.14]

          IPP FaxOut Service [PWG5100.15]

          IPP Transaction-Based Printing Extensions [PWG5100.16]

          IPP Scan Service (SCAN) [PWG5100.17]

          IPP Shared Infrastructure Extensions (INFRA) [PWG5100.18]

          IPP Implementor's Guide v2.0 (IG) [PWG5100.19]

       This document is organized as follows:

       o  The rest of Section 1 is an introduction to the IPP simplified
          model for distributed printing;

       o  Section 2 defines the terminology and conventions used within this
          document;

       o  Section 3 introduces the object types covered in this document
          with their basic behaviors, attributes, and interactions;

       o  Section 4 defines the core operations for IPP/1.1.  IPP operations
          are synchronous -- each operation has both a request and a
          response;

       o  Section 5 defines the core attributes (and their syntaxes) that
          are used in the model;

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       o  Sections 6 and 7 summarize the implementation conformance
          requirements for objects that support the protocol and IANA
          considerations, respectively;

       o  Sections 8 and 9 cover the internationalization and security
          considerations for IPP; and

       o  The appendices provide a reference for status-code values,
          processing of IPP attributes, and the generic directory schema.

    1.1.  Simplified Printing Model

       In order to achieve its goal of realizing a workable printing
       protocol for the Internet, the Internet Printing Protocol (IPP) is
       based on a simplified printing model that abstracts the many
       components of real-world printing solutions.  The Internet is a
       distributed computing environment where requesters of print services
       (Clients, applications, Printer drivers, etc.) cooperate and interact
       with print service providers.  This document (sometimes referred to
       here as the "Model and Semantics" document) describes a simple,
       abstract model for IPP even though the underlying configurations can
       be complex "n-tier" client/server systems.  An important simplifying
       step in the IPP Model is to expose only the key objects and
       interfaces required for printing.  The model described in this
       document does not include features, interfaces, and relationships
       that are beyond the scope of IPP/1.1.  IPP/1.1 incorporates many of
       the relevant ideas and lessons learned from other specification and
       development efforts [HTPP] [ISO10175] [LDPA] [P1387.4] [PSIS]
       [RFC1179] [SWP].  IPP is heavily influenced by the printing model
       introduced in the Document Printing Application (DPA) [ISO10175]
       standard.  Although DPA specifies both End User and administrative
       features, IPP/1.1 focuses primarily on End User functionality with a
       few additional OPTIONAL operations for Administrators and Operators.

       The IPP Model encapsulates the important components of distributed
       printing into the following IPP object types:

       o  Printer (Section 3.1)

       o  Job (Section 3.2)

       o  Document (see [PWG5100.5])

       o  Subscription (see [RFC3995])

       Each object type has an associated set of operations (see Section 4)
       and attributes (see Section 5).

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       It is important, however, to understand that in real system
       implementations (which lie underneath the abstracted IPP Model),
       there are other components of a print service that are not explicitly
       defined in the IPP Model.  The following figure illustrates where IPP
       fits with respect to these other components.

                                    +----------------+
                                    |   Application  |
                          o         + . . . . . . .  |
                         \|/        |    Spooler     |
                         / \        + . . . . . . .  |   +---------+
                       End User     | Printer Driver |---|  File   |
             +-----------+ +-----+  +-------+--------+   +----+----+
             |  Browser  | | GUI |          |                 |
             +-----+-----+ +--+--+          |                 |
                   |          |             |                 |
                   |      +---+-------------+--+              |
       N   D   S   |      |      IPP Client    |--------------+
       O   I   E   |      +---------+----------+
       T   R   C   |                |
       I   E   U   |
       F   C   R   -------------- Transport -------------------
       I   T   I
       C   O   T                    |         --+
       A   R   Y           +--------+--------+  |
       T   Y               |    IPP Server   |  |
       I                   +--------+--------+  |
       O                            |           |
       N                   +-----------------+  | IPP Printer
                           |  Print Service  |  |
                           +-----------------+  |
                                    |         --+
                           +-----------------+
                           | Output Device(s)|
                           +-----------------+

                                Figure 1: IPP Model

       An IPP Printer object ("Printer") encapsulates the functions normally
       associated with physical Output Devices along with the spooling,
       scheduling, and multiple device management functions often associated
       with a print server.  Printers are optionally registered as entries
       in a directory where End Users find and select them based on some
       sort of filtered context-based searching mechanism (see Appendix D).
       The directory is used to store relatively static information about
       the Printer, allowing End Users to search for and find Printers that
       match their search criteria -- for example, name, location, context,
       Printer capabilities, etc.  The more dynamic information, such as

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       state, currently loaded and ready media, number of Jobs at the
       Printer, errors, warnings, and so forth, is directly associated with
       the Printer itself rather than with the entry in the directory, which
       only references the Printer.

       IPP Clients ("Clients") implement IPP on the Client side and give
       End Users (or programs running on behalf of End Users) the ability to
       query Printers and submit and manage Print Jobs.  An IPP server is
       just that part of the Printer object that implements the server-side
       protocol.  The rest of the Printer object implements (or gateways
       into) the application semantics of the print service itself.
       Printers can be embedded in an Output Device or can be implemented on
       a host on the network that communicates with an Output Device.

       When a Job is submitted to the Printer and the Printer has validated
       the attributes in the submission request, the Printer creates a new
       IPP Job object ("Job").  The End User then interacts with this new
       Job to query its status and monitor the progress of the Job.  An
       End User can also cancel their Print Jobs by using the Job's
       Cancel-Job operation.  An End User can also hold, release, and
       restart their Print Jobs using the Job's OPTIONAL Hold-Job,
       Release-Job, and Restart-Job operations, if implemented.

       A privileged Operator or Administrator of a Printer can cancel, hold,
       release, and restart any user's Job using the REQUIRED Cancel-Job and
       the OPTIONAL Hold-Job, Release-Job, and Restart-Job operations.  In
       addition, a privileged Operator or Administrator of a Printer can
       pause, resume, or purge (Jobs from) a Printer using the OPTIONAL
       Pause-Printer, Resume-Printer, and Purge-Jobs operations, if
       implemented.

       The notification service is defined in "Internet Printing Protocol
       (IPP): Event Notifications and Subscriptions" [RFC3995].  By using
       such a notification service, the End User is able to register for and
       receive Printer-specific and Job-specific events asynchronously.
       Otherwise, an End User can query the status of Printers and can
       follow the progress of Jobs by polling using the
       Get-Printer-Attributes, Get-Jobs, and Get-Job-Attributes operations.

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    2.  Conventions Used in This Document

    2.1.  Requirements Language

       The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
       "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
       document are to be interpreted as described in [RFC2119].

       The key word "DEPRECATED" in this document refers to an operation,
       attribute, or value that SHOULD NOT be used or supported in new
       implementations.

    2.2.  Printing Terminology

       Client: Initiator of outgoing IPP session requests and sender of
       outgoing IPP operation requests (Hypertext Transfer Protocol
       (HTTP/1.1) user agent, as defined in [RFC7230]).

       Document: An object created and managed by a Printer that contains
       description, processing, and status information.  A Document object
       can have attached data and is bound to a single Job [PWG5100.5].

       'ipp' URI: An IPP URI as defined in [RFC3510].

       'ipps' URI: An IPP URI as defined in [RFC7472].

       Job: An object created and managed by a Printer that contains
       description, processing, and status information.  The Job also
       contains zero or more Document objects.

       Logical Device: A print server, software service, or gateway that
       processes Jobs and either forwards or stores the processed Job or
       uses one or more Physical Devices to render output.

       Output Device: A single Logical or Physical Device.

       Physical Device: A hardware implementation of an endpoint device,
       e.g., a marking engine, a fax modem, etc.

       Printer: Listener for incoming IPP session requests and receiver of
       incoming IPP operation requests (HTTP/1.1 server, as defined in
       [RFC7230]) that represents one or more Physical Devices or a Logical
       Device.

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    2.3.  Model Terminology

    2.3.1.  Administrator

       An End User who is also authorized to manage all aspects of an Output
       Device or Printer, including creating the Printer instances and
       controlling the authorization of other End Users and Operators
       [RFC2567].

    2.3.2.  Attributes

       An attribute is an item of information that is associated with an
       instance of an IPP object (Printer, Job, etc.).  An attribute
       consists of an attribute name and one or more attribute values.  Each
       attribute has a specific attribute syntax.  All object attributes are
       defined in Section 5, and all operation attributes are defined in
       Section 4.

       Job Template attributes are described in Section 5.2.  The Client
       optionally supplies Job Template attributes in a Job Creation request
       (operation requests that create Job objects).  The Printer object has
       associated attributes that define supported and default values for
       the Printer.

    2.3.2.1.  Attribute Group Name

       Related attributes are grouped into named groups.  The name of the
       group is a keyword.  The group name can be used in place of naming
       all the attributes in the group explicitly.  Attribute groups are
       defined in Section 4.

    2.3.2.2.  Attribute Name

       Each attribute is uniquely identified in this document by its
       attribute name.  An attribute name is a keyword.  The keyword
       attribute name is given in the section title in this document that
       describes that attribute.  In running text in this document,
       attribute names are indicated inside double quotation marks (") where
       the quotation marks are not part of the keyword itself.

    2.3.2.3.  Attribute Syntax

       Each attribute is defined using an explicit syntax type.  In this
       document, each syntax type is defined as a keyword with specific
       meaning.  The "Encoding and Transport" document [RFC8010] indicates
       the actual "on-the-wire" encoding rules for each syntax type.
       Attribute syntax types are defined in Section 5.1.

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    2.3.2.4.  Attribute Value

       Each attribute has one or more values.  Attribute values are
       represented in the syntax type specified for that attribute.  In
       running text in this document, attribute values are indicated inside
       single quotation marks ('), whether their attribute syntax is
       keyword, integer, text, etc. where the quotation marks are not part
       of the value itself.

    2.3.3.  End User

       An End User is a person or software process that is authorized to
       perform basic printing functions, including finding/locating a
       Printer, creating a local instance of a Printer, viewing Printer
       status, viewing Printer capabilities, submitting a Print Job, viewing
       Print Job status, and altering the attributes of a Print Job
       [RFC2567].

    2.3.4.  Impression

       An Impression is the content imposed upon one side of a Media Sheet
       by a marking engine, independent of the number of times that the
       sheet side passes any marker.  An Impression contains one or more
       Input Pages that are imposed (scaled, translated, and/or rotated)
       during processing of the Document data.

    2.3.5.  Input Page

       An Input Page is a page according to the definition of "pages" in the
       language used to express the Document data.

    2.3.6.  Job Creation Operation

       A Job Creation operation is any operation that causes the creation of
       a Job object, e.g., the Create-Job, Print-Job, and Print-URI
       operations defined in this document.

    2.3.7.  Keyword

       Keywords are used within this document as identifiers of semantic
       entities within the abstract model (see Section 5.1.4).  Attribute
       names, some attribute values, attribute syntaxes, and attribute group
       names are represented as keywords.

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    2.3.8.  Media Sheet

       A Media Sheet is a single instance of a medium, whether printing on
       one or both sides of the medium.  Media Sheets also include sections
       of roll media.

    2.3.9.  Operator

       An Operator is an End User that also has special rights on the Output
       Device or Printer.  The Operator typically monitors the status of the
       Printer and also manages and controls the Jobs at the Output Device
       [RFC2567].  The Operator is allowed to query and control the Printer,
       Jobs, and Documents based on site policy.

    2.3.10.  Set

       A Set is a logical boundary between the delivered Media Sheets of a
       printed Job.  For example, in the case of a ten-page single Document
       with collated pages and a request for 50 copies, each of the 50
       printed copies of the Document constitutes a Set.  If the pages were
       uncollated, then 50 copies of each of the individual pages within the
       Document would represent each Set.  Finishing processes operate on
       Sets.

    2.3.11.  Support of Attributes

       By definition, a Printer supports an attribute only if that Printer
       accepts it in a request or responds with the corresponding attribute
       populated with some value(s) in a response to a query for that
       attribute.  A Printer supports an attribute value if the value is one
       of the Printer's "supported values" attributes.  The device behind a
       Printer can exhibit a behavior that corresponds to some IPP
       attribute, but if the Printer, when queried for that attribute,
       doesn't respond with the attribute, then as far as IPP is concerned,
       that implementation does not support that feature.  If the Printer's
       "xxx-supported" attribute is not populated with a particular value
       (even if that value is a legal value for that attribute), then that
       Printer does not support that particular value.

       A conforming implementation supports all REQUIRED attributes.
       However, even for REQUIRED attributes, conformance to IPP does not
       mandate that all implementations support all possible values
       representing all possible Job processing behaviors and features.  For
       example, if a given instance of a Printer supports only certain
       Document formats, then that Printer responds with the
       "document-format-supported" attribute populated with a set of values,
       or possibly only one value, taken from the entire set of possible
       values defined for that attribute.  This limited set of values

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       represents the Printer's set of supported Document formats.
       Supporting an attribute and some set of values for that attribute
       enables IPP End Users to be aware of and make use of those features
       associated with that attribute and those values.  If an
       implementation chooses to not support an attribute or some specific
       value, then IPP End Users would have no ability to make use of that
       feature within the context of IPP itself.  However, due to existing
       practice and legacy systems that are not IPP aware, there might be
       some other mechanism outside the scope of IPP to control or request
       the "unsupported" feature (such as embedded instructions within the
       Document data itself).

       For example, consider the following for the "finishings-supported"
       attribute.

       1)  If a Printer is not physically capable of stapling, the
           "finishings-supported" attribute MUST NOT be populated with the
           value of 'staple'.

       2)  A Printer is physically capable of stapling; however, an
           implementation chooses not to support stapling in the IPP
           "finishings" attribute.  In this case, 'staple' MUST NOT be a
           value in the "finishings-supported" Printer Description
           attribute.  Without support for the value 'staple', an IPP
           End User would have no means within the protocol itself to
           request that a Job be stapled.  However, an existing Document
           data formatter might be able to request that the Document be
           stapled directly with an embedded instruction within the Document
           data.  In this case, the IPP implementation does not "support"
           stapling; however, the End User is still able to have some
           control over the stapling of the completed Job.

       3)  A Printer is physically capable of stapling, and an
           implementation chooses to support stapling in the IPP
           "finishings" attribute.  In this case, 'staple' MUST be a value
           in the "finishings-supported" Printer attribute.  Doing so
           enables End Users to be aware of and make use of the stapling
           feature using IPP attributes.

       Even though support for Job Template attributes by a Printer is
       OPTIONAL in IPP/1.1, Printers whose associated device(s) is capable
       of realizing any feature or function that corresponds to an IPP
       attribute and some associated value SHOULD support that IPP attribute
       and value.

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       The set of values in any of the supported value attributes is set
       (populated) by some administrative process or automatic sensing
       mechanism that is outside the scope of this document.  For
       administrative policy and control reasons, an Administrator can
       choose to make only a subset of possible values visible to the
       End User.  In this case, the real Output Device behind the IPP
       Printer abstraction can be capable of a certain feature; however, an
       Administrator is specifying that access to that feature not be
       exposed to the End User through IPP.  Also, since a Printer can
       represent a logical print device (not just a Physical Device), the
       actual process for supporting a value is undefined and left up to the
       implementation.  However, if a Printer supports a value, some manual
       human action might be needed to realize the semantic action
       associated with the value, but no End User action is required.

       For example, if one of the values in the "finishings-supported"
       attribute is 'staple', the actual process might be an automatic
       staple action by a Physical Device controlled by some command sent to
       the device.  Or, the actual process of stapling might be a manual
       action by an Operator at an Operator-attended Printer.

       For another example of how supported attributes function, consider an
       Administrator who desires to control all Print Jobs so that no Job
       sheets are printed in order to conserve paper.  To force no Job
       sheets, the Administrator sets the only supported value for the
       "job-sheets-supported" attribute to 'none'.  In this case, if a
       Client requests anything except 'none', the Job Creation request is
       rejected or the "job-sheets" value is ignored (depending on the value
       of "ipp-attribute-fidelity").  To force the use of Job start/end
       sheets on all Jobs, the Administrator does not include the value
       'none' in the "job-sheets-supported" attribute.  In this case, if a
       Client requests 'none', the Job Creation request is rejected or the
       "job-sheets" value is ignored (again depending on the value of
       "ipp-attribute-fidelity").

       Job Template attributes will typically have corresponding
       "xxx-supported" and "xxx-default" Printer Description attributes that
       contain the supported and default values for the attribute.  For
       capabilities that are not associated with a Job, the convention is to
       have an "xxx-supported" Printer Description attribute that lists the
       supported values and an "xxx-configured" Printer Description
       attribute that contains the value being used by the Printer.  For
       example, the "charset-supported" Printer Description attribute
       (Section 5.4.18) lists the supported character sets for the Printer
       while the "charset-configured" Printer Description attribute
       (Section 5.4.17) specifies the character set being used by the
       Printer.

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    2.3.12.  Terminating State

       The final state for a Job or other object is called its Terminating
       State.  For example, the 'aborted', 'canceled', and 'completed' Job
       states are Terminating States.

    2.4.  Abbreviations

       ABNF: Augmented Backus-Naur Form [RFC5234]

       ASCII: American Standard Code for Information Interchange [RFC20]

       HTTP: Hypertext Transfer Protocol [RFC7230]

       HTTPS: HTTP over TLS [RFC2818]

       IANA: Internet Assigned Numbers Authority

       IEEE: Institute of Electrical and Electronics Engineers

       IESG: Internet Engineering Steering Group

       IPP: Internet Printing Protocol (this document, [RFC8010], and
       [PWG5100.12])

       ISTO: IEEE Industry Standards and Technology Organization

       LPD: Line Printer Daemon Protocol [RFC1179]

       PWG: IEEE-ISTO Printer Working Group

       RFC: Request for Comments

       TCP: Transmission Control Protocol [RFC793]

       TLS: Transport Layer Security [RFC5246]

       URI: Uniform Resource Identifier [RFC3986]

       URL: Uniform Resource Locator [RFC3986]

       UTF-8: Unicode Transformation Format - 8-bit [RFC3629]

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    3.  IPP Objects

       This document defines IPP objects of types Printer and Job.  Each
       type of object models relevant aspects of a real-world entity such as
       a real Printer or real Print Job.  Each object type is defined as a
       set of possible attributes that can be supported by instances of that
       object type.  For each object (instance), the actual set of supported
       attributes and values describe a specific implementation.  The
       object's attributes and values describe its state, capabilities,
       realizable features, Job processing functions, and default behaviors
       and characteristics.  For example, the Printer object type is defined
       as a set of attributes that each Printer object potentially supports.
       In the same manner, the Job object type is defined as a set of
       attributes that are potentially supported by each Job object.

       Each attribute included in the set of attributes defining an object
       type is labeled as:

       o  "REQUIRED": each object MUST support the attribute.

       o  "RECOMMENDED": each object SHOULD support the attribute.

       o  "OPTIONAL": each object MAY support the attribute.

       Some definitions of attribute values indicate that an object MUST or
       SHOULD support the value; otherwise, support of the value is
       OPTIONAL.  However, if an implementation supports an attribute, it
       MUST support at least one of the possible values for that attribute.

    3.1.  Printer Object

       The major component of the IPP Model is the Printer object.  A
       Printer object implements the server side of the IPP/1.1 protocol.
       Using the protocol, End Users can query the attributes of the Printer
       object and submit Print Jobs to the Printer object.  The actual
       implementation components behind the Printer abstraction can take on
       different forms and different configurations.  However, the model
       abstraction allows the details of the configuration of real
       components to remain opaque to the End User.  Section 4 describes
       each of the Printer operations in detail.

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       The capabilities and state of a Printer object are described by its
       attributes.  Printer attributes are divided into two groups:

       o  "job-template" attributes: These attributes describe supported Job
          processing capabilities and defaults for the Printer object (see
          Section 5.2)

       o  "printer-description" attributes: These attributes describe the
          Printer's identification, state, location, references to other
          sources of information about the Printer object, etc. (see
          Section 5.4)

       Since a Printer object is an abstraction of a generic Document Output
       Device and print service provider, a Printer object could be used to
       represent any real or virtual device with semantics consistent with
       the Printer object, such as a fax device, an imager, or even a CD
       writer.

       Some examples of configurations supporting a Printer object include:

       1.  An Output Device with no spooling capabilities

       2.  An Output Device with a built-in spooler

       3.  A print server supporting IPP with one or more associated Output
           Devices

           3a.  The associated Output Devices are or are not capable of
                spooling Jobs

           3b.  The associated Output Devices possibly support IPP

       Figure 2 shows some examples of how Printers can be realized on top
       of various distributed printing configurations.  The embedded case
       below represents configurations 1 and 2 above.  The "hosted Printer"
       and "fan out" items represent configurations 3a and 3b, respectively.

       In this document, the term "Client" refers to a software entity that
       sends IPP operation requests to an IPP Printer and accepts IPP
       operation responses.  A Client MAY be:

       1.  contained within software controlled by an End User, e.g.,
           activated by the "Print" menu item in an application, or

       2.  the print server component that sends IPP requests to either an
           Output Device or another "downstream" print server.

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       The term "IPP Printer" is a network entity that accepts IPP operation
       requests and returns IPP operation responses.  As such, an IPP
       Printer object MAY be:

       1.  an (embedded) device component that accepts IPP requests and
           controls the device, or

       2.  a component of a print server that accepts IPP requests (where
           the print server controls one or more networked devices using IPP
           or other protocols).

       Legend:

       ##### indicates a Printer object that is
             either embedded in an Output Device or
             hosted in a server.  The Printer object
             might or might not be capable of queuing/spooling.

       any   indicates any network protocol or direct
             connect, including IPP

       embedded Printer:
                                                 Output Device
                                               +---------------+
        O   +--------+                         |  ###########  |
       /|\  | Client |------------IPP------------># Printer #  |
       / \  +--------+                         |  # Object  #  |
                                               |  ###########  |
                                               +---------------+
       hosted Printer:
                                               +---------------+
        O   +--------+        ###########      |               |
       /|\  | Client |--IPP--># Printer #-any->| Output Device |
       / \  +--------+        # Object  #      |               |
                              ###########      +---------------+
                                                +---------------+
       fan out:                                 |               |
                                            +-->| Output Device |
                                        any/    |               |
        O   +--------+      ###########   /     +---------------+
       /|\  | Client |-IPP-># Printer #--*
       / \  +--------+      # Object  #   \     +---------------+
                            ########### any\    |               |
                                            +-->| Output Device |
                                                |               |
                                                +---------------+

                     Figure 2: IPP Printer Object Architecture

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    3.2.  Job Object

       A Job object is used to model a Print Job.  A Job object contains
       zero or more Documents.  The information required to create a Job
       object is sent in a Job Creation request from the End User via an IPP
       Client to the Printer.  The Printer validates the Job Creation
       request, and if the Printer accepts the request, the Printer creates
       the new Job object.  Section 4 describes each of the Job operations
       in detail.

       The characteristics and state of a Job object are described by its
       attributes.  Job attributes are grouped into two groups as follows:

       o  "job-template" attributes: These attributes can be supplied by the
          Client or End User and include Job processing instructions that
          are intended to override any Printer defaults and/or instructions
          embedded within the Document data (see Section 5.2)

       o  "job-description" attributes: These attributes describe the Job's
          identification, state, size, etc.  The Client supplies some of
          these attributes, and the Printer generates others (see
          Section 5.3)

       An implementation MUST support at least one Document per Job object.
       An implementation MAY support multiple Documents per Job object.  A
       Document is either:

       o  a stream of Document data in a format supported by the Printer
          (typically a Page Description Language -- PDL), or

       o  a reference to such a stream of Document data.

       All Job processing instructions are modeled as Job object attributes.
       These attributes are called "Job Template attributes", and they apply
       equally to all Documents within a Job object.

    3.3.  Object Relationships

       IPP objects have relationships that are maintained persistently along
       with the persistent storage of the object attributes.

       A Printer object can represent either one or more physical Output
       Devices or a Logical Device that "processes" Jobs but never actually
       uses a physical Output Device to put marks on paper.  Examples of
       Logical Devices include a web page publisher or a gateway into an
       online Document archive or repository.  A Printer contains zero or
       more Job objects.

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       A Job object is contained by exactly one Printer; however, the
       identical Document data associated with a Job could be sent to either
       the same or a different Printer.  In this case, a second Job object
       would be created that would be almost identical to the first Job;
       however, it would have new (different) Job object identifiers (see
       Section 3.4).

       A Job either is empty (before any Documents have been added) or
       contains one or more Documents.  If the contained Document is a
       stream of Document data, that stream can be contained in only one
       Document.  However, there can be identical copies of the stream in
       other Documents in the same or different Jobs.  If the contained
       Document is just a reference to a stream of Document data, other
       Documents (in the same or different Job(s)) contain the same
       reference.

    3.4.  Object Identity

       All IPP objects (Printers, Jobs, etc.) are identified by a Uniform
       Resource Identifier (URI) [RFC3986] so that they can be persistently
       and unambiguously referenced.  Since every URL is a specialized form
       of a URI, even though the more generic term "URI" is used throughout
       the rest of this document, its usage is intended to cover the more
       specific notion of "URL" as well.

       An Administrator configures Printers to either support or not support
       authentication and/or message privacy using Transport Layer Security
       (TLS) [RFC5246]; the mechanism for security configuration is outside
       the scope of this document.  In some situations, both types of
       connections (both authenticated and unauthenticated) can be
       established using a single communication channel that has some sort
       of negotiation mechanism.  In other situations, multiple
       communication channels are used, one for each type of security
       configuration.  Section 9 provides a full description of all security
       considerations and configurations.

       If a Printer supports more than one communication channel, some or
       all of those channels might support and/or require different security
       mechanisms.  In such cases, an Administrator could expose the
       simultaneous support for these multiple communication channels as
       multiple URIs for a single Printer where each URI represents one of
       the communication channels to the Printer.  To support this
       flexibility, the IPP Printer object type defines a multi-valued
       identification attribute called the "printer-uri-supported" attribute
       that MUST contain at least one URI.  The "printer-uri-supported"
       attribute has two companion attributes, the "uri-security-supported"
       attribute and the "uri-authentication-supported" attribute.  Both
       have the same cardinality as "printer-uri-supported".  The purpose of

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       the "uri-security-supported" attribute is to indicate the security
       mechanisms (if any) used for each URI listed in
       "printer-uri-supported".  The purpose of the
       "uri-authentication-supported" attribute is to indicate the
       authentication mechanisms (if any) used for each URI listed in
       "printer-uri-supported".  These three attributes are fully described
       in Sections 5.4.1, 5.4.2, and 5.4.3.

       When a Job is submitted to the Printer via a Job Creation request,
       the Client supplies only a single Printer URI.  The Client-supplied
       Printer URI MUST be one of the values in the "printer-uri-supported"
       Printer attribute.

       IPP/1.1 does not specify how the Client obtains the Client-supplied
       URI, but it is RECOMMENDED that a Printer be registered as an entry
       in a directory service.  End Users and programs can then interrogate
       the directory, searching for Printers.  Appendix D defines a generic
       schema for Printer object entries in the directory service and
       describes how the entry acts as a bridge to the actual IPP Printer.
       The entry in the directory that represents the IPP Printer includes
       the possibly many URIs for that Printer as values in one of its
       attributes.

       When a Client submits a Job Creation request to the Printer, the
       Printer validates the request and creates a new Job object.  The
       Printer assigns the new Job a numeric identifier that is stored in
       the "job-id" Job attribute and a URI that is stored in the "job-uri"
       Job attribute.  Both the numeric identifier and URI can then be used
       by Clients as the target for subsequent Job operations; the numeric
       identifier is preferred.  The Printer generates the Job numeric
       identifier and URI based on its configured security policy and the
       URI used by the Client in the Job Creation request.

       For example, consider a Printer that supports both a communication
       channel secured by the use of TLS (using HTTP over TLS with an
       "https" schemed URI) and another open communication channel that is
       not secured with TLS (using a simple "http" schemed URI).  If a
       Client submits a Job using the secure URI, the Printer assigns the
       new Job a secure URI as well.  If a Client were to submit a Job using
       the open-channel URI, the Printer might assign the new Job an
       open-channel URI.  Clients SHOULD use the "printer-uri" and "job-id"
       attributes to target a Job to avoid any ambiguity about the security
       of the communication channel.

       In addition, the Printer also populates the Job's "job-printer-uri"
       attribute.  This is a reference back to the Printer that created the
       Job.  If a Client only has access to a Job's "job-uri" identifier,
       the Client can query the Job's "job-printer-uri" attribute in order

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       to determine which Printer created the Job.  If the Printer supports
       more than one URI, the Printer picks the one URI supplied by the
       Client when creating the Job to build the value for and to populate
       the Job's "job-printer-uri" attribute.

       In addition to identifiers, IPP objects have names -- "printer-name"
       for Printers and "job-name" for Jobs.  An object name is not
       guaranteed to be unique across all instances of all objects.  A
       Printer's name is chosen and set by an Administrator through some
       mechanism outside the scope of this document.  A Job's name can be
       chosen and supplied by the Client submitting the Job.  If the Client
       does not supply a Job name, the Printer generates a name for the new
       Job.  In all cases, the name only has local meaning.

       To summarize:

       o  Each Printer is identified by one or more URIs.  The Printer's
          "printer-uri-supported" attribute contains the URI(s).

       o  The Printer's "uri-security-supported" attribute identifies the
          communication channel security protocols that have been configured
          for the various Printer URIs (e.g., 'tls' or 'none').

       o  The Printer's "uri-authentication-supported" attribute identifies
          the authentication mechanisms that have been configured for the
          various Printer URIs (e.g., 'digest', 'none', etc.).

       o  Each Job is identified by a numeric identifier, which is a 32-bit
          positive integer.  The Job's "job-id" attribute contains the
          Job ID.  The Job ID is only unique within the context of the
          Printer that created the Job.

       o  Each Job is also identified by a URI.  The Job's "job-uri"
          attribute contains the URI, although its use by Clients is
          DEPRECATED.

       o  Each Job has a "job-printer-uri" attribute, which contains the URI
          of the Printer that was used to create the Job.  This attribute is
          used to determine the Printer that created a Job when given only
          the URI for the Job.  This linkage is necessary to determine the
          languages, charsets, and operations that are supported on that Job
          (the basis for such support comes from the creating Printer).

       o  Each Printer has a name, which is not necessarily unique.  The
          Administrator chooses and sets this name through some mechanism
          outside the scope of this IPP/1.1 document.  The Printer's
          "printer-name" attribute contains the name.

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       o  Each Job has a name, which is not necessarily unique.  The Client
          optionally supplies this name in the Job Creation request.  If the
          Client does not supply this name, the Printer generates a name for
          the Job.  The Job's "job-name" attribute contains the name.

    4.  IPP Operations

       IPP objects (Printers, Jobs, etc.) support operations.  An operation
       consists of a request and a response.  When a Client communicates
       with a Printer or its Jobs, the Client issues an operation request to
       the Printer URI and object's numeric identifier, if needed.
       Operation requests and responses have parameters that identify the
       operation.  Operations also have attributes that affect the runtime
       characteristics of the operation (the intended target, localization
       information, etc.).  These operation-specific attributes are called
       "operation attributes" (as compared to object attributes such as
       Printer attributes or Job attributes).  Each request carries along
       with it any operation attributes, object attributes, and/or Document
       data required to perform the operation.  Each request requires a
       response from the object.  Each response indicates success or failure
       of the operation with a status-code as a response parameter.  The
       response contains any operation attributes, object attributes, and/or
       status messages generated during the execution of the operation
       request.

       This section describes the semantics of the IPP operations, both
       requests and responses, in terms of the parameters, attributes, and
       other data associated with each operation.

       The Printer operations defined in this document are:

          Print-Job (Section 4.2.1)

          Print-URI (Section 4.2.2)

          Validate-Job (Section 4.2.3)

          Create-Job (Section 4.2.4)

          Get-Printer-Attributes (Section 4.2.5)

          Get-Jobs (Section 4.2.6)

          Pause-Printer (Section 4.2.7)

          Resume-Printer (Section 4.2.8)

          Purge-Jobs (Section 4.2.9)

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       The Job operations defined in this document are:

          Send-Document (Section 4.3.1)

          Send-URI (Section 4.3.2)

          Cancel-Job (Section 4.3.3)

          Get-Job-Attributes (Section 4.3.4)

          Hold-Job (Section 4.3.5)

          Release-Job (Section 4.3.6)

          Restart-Job (Section 4.3.7)

       The Send-Document and Send-URI Job operations are used to add
       Documents to an existing Job created using the Create-Job operation.

    4.1.  Common Semantics

       All IPP operations require some common parameters and operation
       attributes.  These common elements and their semantic characteristics
       are defined and described in more detail in the following sections.

    4.1.1.  Required Parameters

       Every operation request contains the following REQUIRED parameters:

       o  a "version-number",

       o  an "operation-id",

       o  a "request-id", and

       o  the attributes that are REQUIRED for that type of request.

       Every operation response contains the following REQUIRED parameters:

       o  a "version-number",

       o  a "status-code",

       o  the "request-id" that was supplied in the corresponding request,
          and

       o  the attributes that are REQUIRED for that type of response.

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       The Encoding and Transport document [RFC8010] defines special rules
       for the encoding of these parameters.  All other operation elements
       are represented using the more generic encoding rules for attributes
       and groups of attributes.

    4.1.2.  Operation IDs and Request IDs

       Each IPP operation request includes an identifying "operation-id"
       value.  Valid values are defined in the "operations-supported"
       Printer attribute section (see Section 5.4.15).  The Client specifies
       which operation is being requested by supplying the correct
       "operation-id" value.

       In addition, every invocation of an operation is identified by a
       "request-id" value.  For each request, the Client chooses the
       "request-id", which MUST be an integer (possibly unique, depending on
       Client requirements) in the range from 1 to 2**31 - 1 (inclusive).
       This "request-id" allows Clients to manage multiple outstanding
       requests.  The receiving IPP object (Printer, Job, etc.) copies all
       32 bits of the Client-supplied "request-id" attribute into the
       response so that the Client can match the response with the correct
       outstanding request, even if the "request-id" is out of range.  If
       the request is terminated before the complete "request-id" is
       received, the IPP object rejects the request and returns a response
       with a "request-id" of 0.

       Note: In some cases, the transport protocol underneath IPP might be a
       connection-oriented protocol that would make it impossible for a
       Client to receive responses in any order other than the order in
       which the corresponding requests were sent.  In such cases, the
       "request-id" attribute would not be essential for correct protocol
       operation.  However, in other transport mappings the operation
       responses could come back in any order, in which case the
       "request-id" is essential.

    4.1.3.  Attributes

       Operation requests and responses are both composed of groups of
       attributes and/or Document data.  The attribute groups are:

       o  Operation Attributes: These attributes are passed in the operation
          and affect the IPP object's behavior while processing the
          operation request, and they can affect other attributes or groups
          of attributes.  Some operation attributes describe the Document
          data associated with the Print Job and are associated with new Job
          objects; however, most operation attributes do not persist beyond
          the life of the operation.  The description of each operation
          attribute includes conformance statements indicating which

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          operation attributes are REQUIRED and which are OPTIONAL for an
          IPP object to support, as well as which attributes a Client MUST
          supply in a request and an IPP object MUST supply in a response.

       o  Job Template Attributes: These attributes affect the processing of
          a Job.  A Client MAY supply Job Template attributes in a Job
          Creation request, and the receiving object MUST be prepared to
          receive all supported attributes.  The Job object can later be
          queried to find out what Job Template attributes were originally
          requested in the Job Creation request, and such attributes are
          returned in the response as Job object attributes.  The Printer
          object can be queried about its Job Template attributes to find
          out what type of Job processing capabilities are supported and/or
          what the default Job processing behaviors are, though such
          attributes are returned in the response as Printer object
          attributes.  The "ipp-attribute-fidelity" operation attribute
          affects processing of all Client-supplied Job Template attributes
          -- see Section 4.2.1.1 and Appendix C for a full description of
          "ipp-attribute-fidelity" and its relationship to other attributes.

       o  Job Object Attributes: These attributes are returned in response
          to a query operation directed at a Job object.

       o  Printer Object Attributes: These attributes are returned in
          response to a query operation directed at a Printer object.

       o  Unsupported Attributes: In a Job Creation request, the Client
          supplies a set of operation and Job Template attributes.  If any
          of these attributes or their values are unsupported by the Printer
          object, the Printer object SHOULD return the set of unsupported
          attributes in the response.  Section 4.1.7, Section 4.2.1.2, and
          Appendix C give a full description of how Job Template attributes
          supplied by the Client in a Job Creation request are processed by
          the Printer object and how unsupported attributes are returned to
          the Client.  Because of extensibility, any IPP object might
          receive a request that contains new or unknown attributes or
          values for which it has no support.  In such cases, the IPP object
          processes what it can and returns the unsupported attributes in
          the response.  The Unsupported Attributes group is defined for all
          operation responses for returning unsupported attributes that the
          Client supplied in the request.

       Later in this section, each operation is formally defined by
       identifying the allowed and expected groups of attributes for each
       request and response.  The model identifies a specific order for each
       group in each request or response, but the attributes within each
       group can be in any order, unless specified otherwise.

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       The attributes within a group MUST be unique; if an attribute with
       the same name occurs more than once, the group is malformed.  Clients
       MUST NOT submit such malformed requests, and Printers MUST NOT return
       such malformed responses.  If such a malformed request is submitted
       to a Printer, the Printer MUST either (1) reject the request with the
       'client-error-bad-request' status-code (RECOMMENDED -- see
       Appendix B.1.4.1) or (2) process the request normally after selecting
       only one of the attribute instances, depending on implementation.
       Which attribute is selected when there are duplicate attributes
       depends on implementation.  The IPP Printer MUST NOT use the values
       from more than one such duplicate attribute instance.

       Each attribute definition includes the attribute's name followed by
       the name of its attribute syntax(es) in parentheses.  In addition,
       each 'integer' attribute can be followed by the allowed range in
       parentheses, (m:n), for values of that attribute.  Each 'text' or
       'name' attribute can be followed by the maximum size in octets in
       parentheses, (size), for values of that attribute.  For more details
       on attribute syntax notation, see the descriptions of these attribute
       syntaxes in Section 5.1.

       Note: Document data included in the operation is not strictly an
       attribute, but it is treated as a special attribute group for
       ordering purposes.  The only operations defined in this document that
       support supplying the Document data within an operation request are
       Print-Job and Send-Document.  There are no operations defined in this
       document whose responses include Document data.

       Some operations are REQUIRED for IPP objects to support; the others
       are OPTIONAL (see Section 6.2.2).  Therefore, before using an
       OPTIONAL operation, a Client SHOULD first use the REQUIRED
       Get-Printer-Attributes operation to query the Printer's
       "operations-supported" attribute in order to determine which OPTIONAL
       operations are actually supported.  The Client SHOULD NOT use an
       OPTIONAL operation that is not supported.  When an IPP object
       receives a request to perform an operation it does not support, it
       MUST return the 'server-error-operation-not-supported' status-code
       (see Appendix B.1.5.2).  An IPP object is non-conformant if it does
       not support a REQUIRED operation.

    4.1.4.  Character Set and Natural Language Operation Attributes

       Some Job and Printer attributes have values that are text strings and
       names intended for human understanding rather than machine
       understanding (see the 'text' and 'name' attribute syntax
       descriptions in Section 5.1).  The following sections describe two
       special operation attributes called "attributes-charset" and
       "attributes-natural-language" whose values are used when interpreting

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       other attributes using the 'text' and 'name' attribute syntaxes.  For
       Job Creation operations, the IPP Printer implementation also saves
       these two attributes with the new Job object as Job Status
       attributes.

       The "attributes-charset" and "attributes-natural-language" attributes
       MUST be the first two attributes in every IPP request and response,
       as part of the initial Operation Attributes group of the IPP message.
       The "attributes-charset" attribute MUST be the first attribute in the
       group, and the "attributes-natural-language" attribute MUST be the
       second attribute in the group.

       For the sake of brevity in this document, these operation attribute
       descriptions are not repeated with every operation request and
       response but instead have a reference back to this section.

    4.1.4.1.  Request Operation Attributes

       The Client MUST supply and the Printer object MUST support the
       following REQUIRED operation attributes in every IPP operation
       request:

       "attributes-charset" (charset):

          This operation attribute identifies the charset (coded character
          set and encoding method) used by any 'text' and 'name' attributes
          that the Client is supplying in this request.  It also identifies
          the charset that the Printer object MUST use (if supported) for
          all 'text' and 'name' attributes and status messages that the
          Printer object returns in the response to this request.  See
          Sections 5.1.2 and 5.1.3 for the definitions of the 'text' and
          'name' attribute syntaxes.

          All Clients and IPP objects MUST support the 'utf-8' charset
          [RFC3629] and MAY support additional charsets, provided that they
          are registered with IANA [RFC2978] [IANA-CS].  If the Printer
          object does not support the Client-supplied charset value, the
          Printer object MUST reject the request, set the
          "attributes-charset" to 'utf-8' in the response, and return the
          'client-error-charset-not-supported' status-code and any 'text' or
          'name' attributes using the 'utf-8' charset.  The Printer MAY
          return any attributes in the Unsupported Attributes group (see
          Sections 4.1.7 and 4.2.1.2).  The Printer object MUST indicate the
          charset(s) supported as the values of the "charset-supported"
          Printer attribute (see Section 5.4.18), so that the Client can
          query to determine which charset(s) is supported.

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          Note to Client implementors: Since IPP objects are only required
          to support the 'utf-8' charset, in order to maximize
          interoperability with multiple IPP object implementations, a
          Client SHOULD supply 'utf-8' in the "attributes-charset" operation
          attribute, even though the Client is only passing and able to
          present a simpler charset, such as US-ASCII [RFC20] or ISO-8859-1
          [ISO8859-1].  Then the Client will have to filter out, perform
          charset conversion on, or replace those characters that are
          returned in the response that it cannot present to its user.  On
          the other hand, if both the Client and the IPP objects also
          support a charset in common besides 'utf-8', the Client can use
          that charset in order to avoid charset conversion or data loss.

          See the 'charset' attribute syntax description in Section 5.1.8
          for the syntax and semantic interpretation of the values of this
          attribute and for example values.

       "attributes-natural-language" (naturalLanguage):

          This operation attribute identifies the natural language [RFC5646]
          used by any 'text' and 'name' attributes that the Client is
          supplying in this request.  This attribute also identifies the
          natural language that the Printer object SHOULD use for all 'text'
          and 'name' attributes and status messages that the Printer object
          returns in the response to this request.  See the
          'naturalLanguage' attribute syntax description in Section 5.1.9
          for the syntax and semantic interpretation of the values of this
          attribute and for example values.

          There are no REQUIRED natural languages required for the Printer
          object to support.  However, the Printer's
          "generated-natural-language-supported" attribute identifies the
          natural languages supported by the Printer object and any
          contained Jobs for all text strings generated by the IPP object.
          A Client MAY query this attribute to determine which natural
          language(s) is supported for generated messages.

          For any of the attributes for which the Printer object generates
          text, i.e., for the "job-state-message", "printer-state-message",
          and status messages (see Section 4.1.6), the Printer object MUST
          be able to generate these text strings in any of its supported
          natural languages.  If the Client requests a natural language that
          is not supported, the Printer object MUST return these generated
          messages in the Printer's configured natural language as specified
          by the Printer's "natural-language-configured" attribute (see
          Section 5.4.19).

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          For other 'text' and 'name' attributes supplied by the Client,
          authentication system, Operator, Administrator, or manufacturer
          (i.e., for "job-originating-user-name", "printer-name" (name),
          "printer-location" (text), "printer-info" (text), and
          "printer-make-and-model" (text)), the Printer object is only
          required to support the configured natural language of the Printer
          identified by the Printer's "natural-language-configured"
          attribute, though support of additional natural languages for
          these attributes is permitted.

          For any 'text' or 'name' attribute in the request that is in a
          different natural language than the value supplied in the
          "attributes-natural-language" operation attribute, the Client MUST
          use the Natural Language Override mechanism (see Sections 5.1.2.2
          and 5.1.3.2) for each such attribute value supplied.  The Client
          MAY use the Natural Language Override mechanism redundantly, i.e.,
          use it even when the value is in the same natural language as the
          value supplied in the "attributes-natural-language" operation
          attribute of the request.

          The IPP object MUST accept any natural language and any Natural
          Language Override, whether the IPP object supports that natural
          language or not (and independent of the value of the
          "ipp-attribute-fidelity" operation attribute).  That is, the IPP
          object accepts all Client-supplied values no matter what the
          values are in the Printer's "generated-natural-language-supported"
          attribute.  That attribute,
          "generated-natural-language-supported", only applies to generated
          messages, not Client-supplied messages.  The IPP object MUST
          remember that natural language for all Client-supplied attributes,
          and when returning those attributes in response to a query, the
          IPP object MUST indicate that natural language.

          Each value whose attribute syntax type is 'text' or 'name' (see
          Sections 5.1.2 and 5.1.3) has an Associated Natural Language.
          This document does not specify how this association is stored in a
          Printer or Job object.  When such a value is encoded in a request
          or response, the natural language is either implicit or explicit:

          *  In the implicit case, the value contains only the text/name
             value, and the language is specified by the
             "attributes-natural-language" operation attribute in the
             request or response (see Sections 5.1.2.1 and 5.1.3.1).

          *  In the explicit case (also known as the Natural Language
             Override case), the value contains both the language and the
             text/name value (see Sections 5.1.2.2 and 5.1.3.2).

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          For example, the "job-name" attribute MAY be supplied by the
          Client in a Job Creation request.  The text value for this
          attribute will be in the natural language identified by the
          "attribute-natural-language" attribute, or if different, as
          identified by the Natural Language Override mechanism.  If
          supplied, the IPP object will use the value of the "job-name"
          attribute to populate the Job's "job-name" attribute.  Whenever
          any Client queries the Job's "job-name" attribute, the IPP object
          returns the attribute as stored and uses the Natural Language
          Override mechanism to specify the natural language, if it is
          different from that reported in the "attributes-natural-language"
          operation attribute of the response.  The IPP object MAY use the
          Natural Language Override mechanism redundantly, i.e., use it even
          when the value is in the same natural language as the value
          supplied in the "attributes-natural-language" operation attribute
          of the response.

          An IPP object MUST NOT reject a request based on a supplied
          natural language in an "attributes-natural-language" operation
          attribute or in any attribute that uses the Natural Language
          Override.

          Note: Supplying 'text' or 'name' attributes with an incompatible
          combination of natural language and charset can cause undesired
          behavior.  For example, suppose a Printer supports charsets
          'utf-8', 'iso-8859-1', and 'iso-8859-7'.  Suppose also that it
          supports natural languages 'en' (English), 'fr' (French), and 'el'
          (Greek).  Although the Printer supports the charset 'iso-8859-1'
          and natural language 'el', it probably does not support the
          combination of Greek text strings using the 'iso-8859-1' charset.
          The Printer handles this apparent incompatibility differently,
          depending on the context in which it occurs:

          *  In a Job Creation request: If the Client supplies a 'text' or
             'name' attribute (for example, the "job-name" operation
             attribute) that uses an apparently incompatible combination, it
             is a Client choice that does not affect the Printer or its
             correct operation.  Therefore, the Printer simply accepts the
             Client-supplied value, stores it with the Job, and responds
             back with the same combination whenever the Client (or any
             Client) queries for that attribute.

          *  In a query-type operation, like Get-Printer-Attributes: If the
             Client requests an apparently incompatible combination, the
             Printer responds (as described in Section 4.1.4.2) using the
             Printer's configured natural language rather than the natural
             language requested by the Client.

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          In either case, the Printer does not reject the request because of
          the apparent incompatibility.  The potential incompatible
          combination of charset and natural language can occur either at
          the global operation level or at the Natural Language Override
          attribute-by-attribute level.  In addition, since the response
          always includes explicit charset and natural language information,
          there is never any question or ambiguity in how the Client
          interprets the response.

    4.1.4.2.  Response Operation Attributes

       The Printer MUST supply and the Client MUST support the following
       REQUIRED operation attributes in every IPP/1.1 operation response:

       "attributes-charset" (charset):

          This operation attribute identifies the charset used by any 'text'
          and 'name' attributes that the Printer object is returning in this
          response.  The value in this response MUST be the same value as
          the "attributes-charset" operation attribute supplied by the
          Client in the request.  If this is not possible (i.e., the charset
          requested is not supported), the request would have been rejected.
          See "attributes-charset" described in Section 4.1.4.1 above.

          If the Printer object supports more than just the 'utf-8' charset,
          the Printer object MUST be able to perform code conversion between
          each of the charsets supported on a "highest fidelity possible"
          basis in order to return the 'text' and 'name' attributes in the
          charset requested by the Client.  However, some information loss
          can occur during the charset conversion, depending on the charsets
          involved.  For example, depending on implementation, the Printer
          object can convert from a UTF-8 'a' to a US-ASCII 'a' (with no
          loss of information); from an ISO Latin 1 CAPITAL LETTER A WITH
          ACUTE ACCENT to US-ASCII 'A' (losing the accent); or from a UTF-8
          Japanese Kanji character to some ISO Latin 1 error character
          indication such as '?', a decimal code equivalent, or the absence
          of a character.

          Whether an implementation that supports more than one charset
          stores the data in the charset supplied by the Client or performs
          code conversion to one of the other supported charsets depends on
          implementation.  The strategy should try to minimize loss of
          information during code conversion.  On each response, such an
          implementation converts from its internal charset to that
          requested.

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       "attributes-natural-language" (naturalLanguage):

          This operation attribute identifies the natural language used by
          any 'text' and 'name' attributes that the IPP object is returning
          in this response.  Unlike the "attributes-charset" operation
          attribute, the IPP object MAY return the natural language of the
          Job object or the Printer's configured natural language as
          identified by the Printer's "natural-language-configured"
          attribute, rather than the natural language supplied by the
          Client.  For any 'text' or 'name' attribute or status message in
          the response that is in a different natural language than the
          value returned in the "attributes-natural-language" operation
          attribute, the IPP object MUST use the Natural Language Override
          mechanism (see Sections 5.1.2.2 and 5.1.3.2) on each attribute
          value returned.  The IPP object MAY use the Natural Language
          Override mechanism redundantly, i.e., use it even when the value
          is in the same natural language as the value supplied in the
          "attributes-natural-language" operation attribute of the response.

    4.1.5.  Operation Targets

       All IPP operations are directed at IPP objects.  For Printer
       operations, the operation is always directed at a Printer object
       using one of its URIs, i.e., one of the values in the Printer's
       "printer-uri-supported" attribute.  Even if the Printer object
       supports more than one URI, the Client supplies only one URI as the
       target of the operation.  The Client identifies the target object by
       supplying the correct URI in the "printer-uri" operation attribute.

       For Job operations, the operation is directed at either:

       o  The Printer object that created the Job object using the Printer
          object's URI and the Job's numeric identifier (Job ID).  Since the
          Printer object that created the Job object generated the Job ID,
          it MUST be able to correctly associate the Client-supplied Job ID
          with the correct Job object.  The Client supplies the Printer's
          URI in the "printer-uri" operation attribute and the Job ID in the
          "job-id" operation attribute.

       o  The Job object itself using the Job's URI.  In this case, the
          Client identifies the target object by supplying the correct URI
          in the "job-uri" (uri) operation attribute (Section 5.3.2).

       Clients SHOULD send the "printer-uri" and "job-id" operation
       attributes in Job operations.

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       If the operation is directed at the Job object directly using the
       Job's URI, the Client MUST NOT include the redundant "job-id"
       operation attribute.

       The operation target attributes are REQUIRED operation attributes
       that are included in every operation request.  Like the charset and
       natural language attributes (see Section 4.1.4), the operation target
       attributes are specially ordered operation attributes.  In all cases,
       the operation target attributes immediately follow the
       "attributes-charset" and "attributes-natural-language" attributes
       within the Operation Attributes group; however, the specific ordering
       rules are as follows:

       o  In the case where there is only one operation target attribute
          (i.e., either only the "printer-uri" attribute or only the
          "job-uri" attribute), that attribute MUST be the third attribute
          in the Operation Attributes group.

       o  In the case where Job operations use two operation target
          attributes (i.e., the "printer-uri" and "job-id" attributes), the
          "printer-uri" attribute MUST be the third attribute and the
          "job-id" attribute MUST be the fourth attribute.

       In all cases, the target URIs contained within the body of IPP
       operation requests and responses MUST be in absolute format rather
       than relative format (a relative URL identifies a resource with the
       scope of the HTTP server, but does not include scheme, host,
       or port).

       The following rules apply to the use of port numbers in URIs that
       identify IPP objects:

       1.  If the URI scheme allows the port number to be explicitly
           included in the URI string, and a port number is specified within
           the URI, then that port number MUST be used by the Client to
           contact the IPP object.

       2.  If the URI scheme allows the port number to be explicitly
           included in the URI string, and a port number is not specified
           within the URI, then the default port number implied by that URI
           scheme MUST be used by the Client to contact the IPP object.

       3.  If the URI scheme does not allow an explicit port number to be
           specified within the URI, then the default port number implied by
           that URI MUST be used by the Client to contact the IPP object.

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       Note: "Internet Printing Protocol/1.1: IPP URL Scheme" [RFC3510] and
       "Internet Printing Protocol (IPP) over HTTPS Transport Binding and
       the 'ipps' URI Scheme" [RFC7472] define the mapping of IPP onto HTTP
       and HTTPS, respectively, and define and register a default port
       number.

    4.1.6.  Operation Response Status-Code Values and Status Messages

       Every operation response includes a REQUIRED "status-code" parameter,
       SHOULD include the "status-message" operation attribute, and MAY
       include the "detailed-status-message" operation attribute.  The
       Print-URI and Send-URI response MAY also include the
       "document-access-error" operation attribute.

    4.1.6.1.  "status-code" (type2 enum)

       The REQUIRED "status-code" parameter provides information on the
       processing of a request.

       The status-code is intended for use by automata.  A Client
       implementation of IPP SHOULD convert status-code values into any
       localized message that has semantic meaning to the End User.

       The "status-code" value is a numeric value that has semantic meaning.
       The "status-code" syntax is similar to a "type2 enum" (see
       Section 5.1 ("Attribute Syntaxes")), except that values can range
       only from 0x0000 to 0x7fff.  Appendix B describes and assigns the
       status-code values, and suggests a corresponding status message for
       each status-code for use by the Client when the user's natural
       language is English.

       If the Printer performs an operation with no errors and it encounters
       no problems, it MUST return the status-code 'successful-ok' in the
       response.  See Appendix B.

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       If the Client supplies unsupported values for the following
       parameters or operation attributes, the Printer object MUST reject
       the operation, MAY return the unsupported attribute value in the
       Unsupported Attributes group, and MUST return the indicated
       status-code:

       +---------------------+---------------------------------------------+
       | Parameter/Attribute | Status-Code                                 |
       +---------------------+---------------------------------------------+
       | version-number      | server-error-version-not-supported          |
       +---------------------+---------------------------------------------+
       | operation-id        | server-error-operation-not-supported        |
       +---------------------+---------------------------------------------+
       | attributes-charset  | client-error-charset-not-supported          |
       +---------------------+---------------------------------------------+
       | compression         | client-error-compression-not-supported      |
       +---------------------+---------------------------------------------+
       | document-format     | client-error-document-format-not-supported  |
       +---------------------+---------------------------------------------+
       | document-uri        | client-error-uri-scheme-not-supported,      |
       |                     | client-error-document-access-error          |
       +---------------------+---------------------------------------------+

                   Table 1: Status-Code Values for All Requests

       If the Client supplies unsupported values for other attributes, or
       unsupported attributes, the Printer returns the status-code defined
       in Section 4.1.7 ("Unsupported Attributes").

    4.1.6.2.  "status-message" (text(255))

       The RECOMMENDED "status-message" operation attribute provides a short
       textual description of the status of the operation.  The
       "status-message" attribute's syntax is "text(255)", so the maximum
       length is 255 octets (see Section 5.1.2).  The status message is
       intended for the human End User.  If a response does include a
       "status-message" attribute, an IPP Client can examine or display the
       messages in some implementation-specific manner.  The
       "status-message" attribute is especially useful for a later version
       of a Printer to return as supplemental information for the human
       user, to accompany a status-code that an earlier version of a Client
       might not understand.

       If the Printer supports the "status-message" operation attribute, it
       MUST be able to generate this message in any of the natural languages
       identified by the Printer's "generated-natural-language-supported"
       attribute and MUST honor any supported value for the
       "attributes-natural-language" operation attribute (Section 4.1.4.1)

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       of the Client request.  Appendix B suggests the text for the status
       message returned by the Printer for use with the English natural
       language.

       As described in Section 4.1.4.1, for any returned 'text' attribute,
       if there is a choice for generating this message, the Printer uses
       the natural language indicated by the value of
       "attributes-natural-language" in the Client request, if supported;
       otherwise, the Printer uses the value in the Printer's own
       "natural-language-configured" attribute.

       If the Printer supports the "status-message" operation attribute, it
       SHOULD use the REQUIRED 'utf-8' charset to return a status message
       for the following error status-code values (see Appendix B):
       'client-error-bad-request', 'client-error-charset-not-supported',
       'server-error-internal-error',
       'server-error-operation-not-supported', and
       'server-error-version-not-supported'.  In this case, it MUST set the
       value of the "attributes-charset" operation attribute to 'utf-8' in
       the error response.

    4.1.6.3.  "detailed-status-message" (text(MAX))

       The OPTIONAL "detailed-status-message" operation attribute provides
       additional more-detailed technical and implementation-specific
       information about the operation for Administrators or other
       experienced technical people.  The "detailed-status-message"
       attribute's syntax is "text(MAX)", so the maximum length is
       1023 octets (see Section 5.1.2).  If the Printer supports the
       "detailed-status-message" operation attribute, the Printer SHOULD
       localize the message, unless such localization would obscure the
       technical meaning of the message.  Clients MUST NOT attempt to parse
       the value of this attribute.  See the "document-access-error"
       operation attribute (Section 4.1.6.4) for additional errors that a
       program can process.

    4.1.6.4.  "document-access-error" (text(MAX))

       This OPTIONAL operation attribute provides additional information
       about any Document access errors encountered by the Printer before it
       returned a response to the Print-URI (Section 4.2.2) or Send-URI
       (Section 4.3.2) operation.  For errors in the protocol identified by
       the URI scheme in the "document-uri" operation attribute, such as
       'http:' or 'ftp:', the error code is returned in parentheses,
       followed by the URI.  For example:

       (404) http://www.example.com/filename.pdf

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       Most Internet protocols use decimal error codes (unlike IPP), so the
       ASCII error code representation is in decimal.

    4.1.7.  Unsupported Attributes

       The Unsupported Attributes group contains attributes that are not
       supported by the operation.  This group is primarily for the Job
       Creation operations, but all operations can return this group.

       A Printer MUST include an Unsupported Attributes group in a response
       if the status-code is one of the following:
       'successful-ok-ignored-or-substituted-attributes',
       'successful-ok-conflicting-attributes',
       'client-error-attributes-or-values-not-supported', or
       'client-error-conflicting-attributes'.

       If the status-code is one of the four specified in the preceding
       paragraph, the Unsupported Attributes group MUST contain all of those
       attributes and only those attributes that are:

       a.  an operation or Job Template attribute supplied in the request,
           and

       b.  unsupported by the Printer.  See below for details on the three
           categories of "unsupported" attributes.

       If the status-code is one of those in Table 1 in Section 4.1.6.1, the
       OPTIONAL Unsupported Attributes group contains the unsupported
       parameter or attribute indicated in that table.

       If the Printer is not returning any unsupported attributes in the
       response, the Printer SHOULD omit the Unsupported Attributes group
       rather than sending an empty group.  However, a Client MUST be able
       to accept an empty group.

       Unsupported attributes fall into three categories:

       1.  The Printer does not support the supplied attribute (no matter
           what the attribute syntax or value).

       2.  The Printer does support the attribute, but it does not support
           some or all of the particular attribute syntaxes or values
           supplied by the Client, i.e., the Printer does not have those
           attribute syntaxes or values in its corresponding "xxx-supported"
           attribute.

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       3.  The Printer does support the attributes and values supplied, but
           the particular values are in conflict with one another, because
           they violate a constraint, such as not being able to staple
           transparencies.

       In the case of an unsupported attribute name, the Printer returns the
       Client-supplied attribute with a substituted value of 'unsupported'.
       This value's syntax type is "out-of-band", and its encoding is
       defined by special rules for "out-of-band" values in the Encoding and
       Transport document [RFC8010].  Its value indicates no support for the
       attribute itself -- see the beginning of Section 5.1 in this
       document.

       In the case of a supported attribute with one or more unsupported
       attribute syntaxes or values, the Printer simply returns the
       Client-supplied attribute with the unsupported attribute syntaxes or
       values as supplied by the Client.  This indicates support for the
       attribute but no support for that particular attribute syntax or
       value.  If the Client supplies a multi-valued attribute with more
       than one value and the Printer supports the attribute but only
       supports a subset of the Client-supplied attribute syntaxes or
       values, the Printer MUST return only those attribute syntaxes or
       values that are unsupported.

       In the case of two (or more) supported attribute values that are in
       conflict with one another (although each is supported independently,
       the values conflict when requested together within the same Job), the
       Printer MUST return all the values that it ignores or substitutes to
       resolve the conflict but not any of the values that it is still
       using.  The choice for exactly how to resolve the conflict is
       implementation dependent.  See Section 4.2.1.2 and Appendix C.  See
       the Implementor's Guides [RFC3196] [PWG5100.19] for examples.

    4.1.8.  Versions

       Each operation request and response carries with it a
       "version-number" parameter.  Each value of the "version-number"
       parameter is in the form "X.Y" where X is the major version number
       and Y is the minor version number.  By including a version number in
       the Client request, it allows the Client to identify which version of
       IPP it is interested in using, i.e., the version whose conformance
       requirements the Client can depend upon the Printer to meet.

       If the IPP object does not support that major version number supplied
       by the Client, i.e., the "major version number" portion of the
       "version-number" parameter does not match any of the values of the
       Printer's "ipp-versions-supported" attribute (see Section 5.4.14),
       the object MUST respond with a status-code of

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       'server-error-version-not-supported' along with the closest version
       number that is supported (see Appendix B.1.5.4).  If the major
       version number is supported but the minor version number is not, the
       IPP object SHOULD accept the request and attempt to perform it (or
       reject the request if the operation is not supported); otherwise, it
       rejects the request and returns the
       'server-error-version-not-supported' status-code.  In all cases, the
       IPP object MUST return the "version-number" value that it supports
       that is closest to the version number supplied by the Client in the
       request.

       There is no version negotiation per se.  However, if a Client has
       received a 'server-error-version-not-supported' status-code from an
       IPP object, the Client SHOULD try again with a different version
       number.  A Client MAY also determine the versions supported either
       from a directory that conforms to Appendix D or by querying the
       Printer's "ipp-versions-supported" attribute (see Section 5.4.14) to
       determine which versions are supported.

       An IPP/1.1 object implementation MUST support version '1.1', i.e.,
       meet the conformance requirements for IPP/1.1 as specified in this
       document and [RFC8010].  IPP implementations SHOULD accept any
       request with the major version '1' or '2', or reject the request if
       the operation is not supported.

       There is only one notion of "version number" that covers both IPP
       Model and IPP protocol changes.  Changes to the major version number
       of the Model and Semantics document can indicate structural or
       syntactic changes that make it impossible for older versions of IPP
       Clients and Printers to correctly parse and correctly process the new
       or changed attributes, operations, and responses.  If the major
       version number changes, the minor version number is set to zero.  As
       an example, adding the REQUIRED "ipp-attribute-fidelity" attribute to
       version '1.1' (if it had not been part of version '1.0') would have
       required a change to the major version number, since an IPP/1.0
       Printer would not have processed a request with the correct semantics
       that contained the "ipp-attribute-fidelity" attribute that it did not
       know about.  Items that might affect the changing of the major
       version number include any changes to the Model and Semantics
       document (this document) or the Encoding and Transport document
       [RFC8010] itself, such as:

       o  reordering of ordered attributes or attribute sets

       o  changes to the syntax of existing attributes

       o  adding REQUIRED (for an IPP object to support) Operation
          Attributes groups

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       o  adding values to existing REQUIRED operation attributes

       o  adding REQUIRED operations

       Changes to the minor version number indicate the addition of new
       features, attributes, and attribute values that might not be
       understood by all IPP objects but that can be ignored if not
       understood.  Items that might affect the changing of the minor
       version number include any changes to the model objects and
       attributes but not the encoding and transport rules [RFC8010] (except
       adding attribute syntaxes).  Examples of such changes are:

       o  grouping all extensions not included in a previous version into a
          new version

       o  adding new attribute values

       o  adding new object attributes

       o  adding OPTIONAL (for an IPP object to support) operation
          attributes (i.e., those attributes that an IPP object can ignore
          without confusing Clients)

       o  adding OPTIONAL (for an IPP object to support) Operation
          Attributes groups (i.e., those attributes that an IPP object can
          ignore without confusing Clients)

       o  adding new attribute syntaxes

       o  adding OPTIONAL operations

       o  changing Job attributes or Printer attributes from OPTIONAL to
          REQUIRED or vice versa

       o  adding OPTIONAL attribute syntaxes to an existing attribute

       The encoding [RFC8010] of the "version-number" parameter MUST NOT
       change over any version number (either major or minor).  This rule
       guarantees that all future versions will be backwards compatible with
       all previous versions (at least for checking the "version-number"
       parameter).  In addition, any protocol elements (attributes, error
       codes, tags, etc.) that are not carried forward from one version to
       the next are DEPRECATED so that they can never be reused with new
       semantics.

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       Implementations that support a certain version SHOULD support all
       previous Standards Track versions.  As each new version is defined
       (through the release of a new IPP specification document), that
       version will specify which previous versions MUST and which versions
       SHOULD be supported in compliant implementations.

    4.1.9.  Job Creation Operations

       In order to "submit a Print Job" and create a new Job, a Client
       issues a Job Creation request.  A Job Creation request is any one of
       the following three operation requests:

       o  The Print-Job Request: A Client that wants to submit a Print Job
          with only a single Document can use the Print-Job operation.  The
          operation allows for the Client to "push" the Document data to the
          Printer by including the Document data in the request itself.
          Note that Clients SHOULD instead use the Create-Job and
          Send-Document requests, if supported by the Printer, since they
          allow for Job monitoring and control during submission of the
          Document data.

       o  The Print-URI Request: A Client that wants to submit a Print Job
          with only a single Document (where the Printer "pulls" the
          Document data instead of the Client "pushing" the data to the
          Printer) uses the Print-URI operation.  In this case, the Client
          includes in the request only a URI reference to the Document data
          (not the Document data itself).

       o  The Create-Job Request: A Client that wants to submit a Print Job
          with zero or more Documents uses the Create-Job operation.  This
          operation is followed by an arbitrary number of Send-Document
          and/or Send-URI operations, each creating another Document for the
          newly created Job.  The Send-Document operation includes the
          Document data in the request (the Client "pushes" the Document
          data to the Printer), and the Send-URI operation includes only a
          URI reference to the Document data in the request (the Printer
          "pulls" the Document data from the referenced location).  The last
          Send-Document or Send-URI request for a given Job includes a
          "last-document" operation attribute set to 'true' indicating that
          this is the last request.

       Throughout this document, the term "Job Creation request" is used to
       refer to any of these three operation requests.

       A Create-Job operation followed by only one Send-Document operation
       is semantically equivalent to a Print-Job operation; however, the
       Client SHOULD use the Create-Job and Send-Document operations (when
       supported) for all Jobs with a single Document to allow for reliable

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       Job control and monitoring.  Print-Job is a REQUIRED operation (all
       implementations MUST support it), whereas Create-Job is a RECOMMENDED
       operation and hence some implementations might not support it.

       Job submission time is the point in time when a Client issues a Job
       Creation request.  The initial state of every Job is the 'pending',
       'pending-held', or 'processing' state (see Section 5.3.7).  When the
       Printer begins processing the Print Job, the Job's state moves to
       'processing'.  This is known as Job processing time.

       At Job submission time and at the time a Validate-Job operation is
       received, the Printer MUST do the following:

       1.  Process the Client-supplied attributes and either accept or
           reject the request

       2.  Validate the syntax of and support for the scheme of any
           Client-supplied URI

       At Job submission time, the Printer MUST validate whether the
       supplied attributes, attribute syntaxes, and values are supported by
       matching them with the Printer's corresponding "xxx-supported"
       attributes.  See Section 4.1.7 for details.  See the Implementor's
       Guides [RFC3196] [PWG5100.19] for guidance on processing Job Creation
       requests.

       At Job submission time, the Printer MAY perform the validation checks
       reserved for Job processing time, such as:

       1.  Validating the format of the Document data

       2.  Validating the actual contents of any Client-supplied URI
           (resolve the reference and follow the link to the Document data)

       At Job submission time, these additional Job processing time
       validation checks are essentially useless, since they require
       actually parsing and interpreting the Document data, are not
       guaranteed to be 100% accurate, and MUST be done, yet again, at Job
       processing time.  Also, in the case of a URI, checking for
       availability at Job submission time does not guarantee availability
       at Job processing time.  In addition, at Job processing time, the
       Printer might discover any of the following conditions that were not
       detectable at Job submission time:

       o  runtime errors in the Document data,

       o  nested Document data that is in an unsupported format,

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       o  the URI reference is no longer valid (i.e., the server hosting the
          Document might be down), or

       o  any other Job processing error.

       At Job submission time, a Printer, especially a non-spooling Printer,
       MAY accept Jobs for which it does not have enough space.  In such a
       situation, a Printer MAY stop reading data from a Client for an
       indefinite period of time.  A Client MUST be prepared for a write
       operation to block for an indefinite period of time (see Section 6.1
       ("Client Conformance Requirements")).

       When a Printer has too little space for starting a new Job, it MAY
       reject a new Job Creation request.  In this case, a Printer MUST
       return a response (in reply to the rejected request) with a
       status-code of 'server-error-busy' (see Appendix B.1.5.8), and it MAY
       close the connection before receiving all bytes of the operation.  A
       Printer SHOULD indicate that it is temporarily unable to accept Jobs
       by setting the 'spool-space-full' value in its
       "printer-state-reasons" attribute and removing the value when it can
       accept another Job (see Section 5.4.12).

       When receiving a 'server-error-busy' status-code in an operation
       response, a Client MUST be prepared for the Printer to close the
       connection before the Client has sent all of the data (especially for
       the Print-Job operation).  A Client MUST be prepared to keep
       submitting a Job Creation request until the Printer accepts the Job
       Creation request.

       At Job processing time, since the Printer has already responded with
       a successful status-code in the response to the Job Creation request,
       if the Printer detects an error, the Printer is unable to inform the
       End User of the error with an operation status-code.  In this case,
       the Printer, depending on the error, can set the Job's "job-state",
       "job-state-reasons", and/or "job-state-message" attributes to the
       appropriate value(s) so that later queries can report the correct Job
       status.

       Note: Asynchronous notification of events is defined in "Internet
       Printing Protocol (IPP): Event Notifications and Subscriptions"
       [RFC3995].

    4.2.  Printer Operations

       All Printer operations are directed at Printers.  A Client MUST
       always supply the "printer-uri" operation attribute in order to
       identify the correct target of the operation.

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    4.2.1.  Print-Job Operation

       This REQUIRED operation allows a Client to submit a Print Job with
       only one Document and supply the Document data (rather than just a
       reference to the data).  See Appendix C for the suggested steps for
       processing Job Creation requests and their operation and Job Template
       attributes.

    4.2.1.1.  Print-Job Request

       The following groups of attributes are supplied as part of the
       Print-Job request:

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.1.  The Printer MUST
             copy these values to the corresponding Job Status attributes
             described in Sections 5.3.19 and 5.3.20.

          Target:

             The "printer-uri" (uri) operation attribute, which is the
             target for this operation as described in Section 4.1.5.

          Requesting User Name:

             The "requesting-user-name" (name(MAX)) attribute SHOULD be
             supplied by the Client as described in Section 9.3.

          "job-name" (name(MAX)):

             The Client MAY supply and the Printer MUST support this
             attribute.  It contains the Client-supplied Job name.  If this
             attribute is supplied by the Client, its value is used for the
             "job-name" attribute of the newly created Job.  The Client MAY
             automatically include any information that will help the
             End User distinguish amongst his/her Jobs, such as the name of
             the application program along with information from the
             Document, such as the Document name, Document subject, or
             source file name.  If this attribute is not supplied by the
             Client, the Printer generates a name to use in the "job-name"
             attribute of the newly created Job (see Section 5.3.5).

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          "ipp-attribute-fidelity" (boolean):

             The Client MAY supply and the Printer MUST support this
             attribute.  The value 'true' indicates that total fidelity to
             Client-supplied Job Template attributes and values is required;
             otherwise, the Printer MUST reject the Print-Job request.  The
             value 'false' indicates that a reasonable attempt to print the
             Job is acceptable and the Printer MUST accept the Print-Job
             request.  If not supplied, the Printer assumes that the value
             is 'false'.  All Printers MUST support both types of Job
             processing.  See Appendix C for a full description of
             "ipp-attribute-fidelity" and its relationship to other
             attributes, especially the Printer's "pdl-override-supported"
             attribute.

          "document-name" (name(MAX)):

             The Client MAY supply and the Printer MUST support this
             attribute.  It contains the Client-supplied Document name.  The
             Document name MAY be different than the Job name.  Typically,
             the Client software automatically supplies the Document name on
             behalf of the End User by using a file name or an
             application-generated name.  If this attribute is supplied, its
             value can be used in a manner defined by each implementation.
             Examples include the following: printed along with the Job (Job
             start sheet, page adornments, etc.), used by accounting or
             resource-tracking management tools, or even stored along with
             the Document as a Document-level attribute.

          "compression" (type2 keyword):

             The Client MAY supply and the Printer MUST support this
             attribute.  The Client-supplied "compression" operation
             attribute identifies the compression algorithm used on the
             Document data.  The following cases exist:

             a.  If the Client omits this attribute, the Printer MUST assume
                 that the data is not compressed, i.e., the Printer follows
                 the rules below as if the Client supplied the "compression"
                 attribute with a value of 'none'.

             b.  If the Client supplies this attribute but the value is not
                 supported by the Printer, i.e., the value is not one of the
                 values of the Printer's "compression-supported" attribute,
                 the Printer MUST reject the request and return the
                 'client-error-compression-not-supported' status-code.  See
                 Section 4.1.7 for details on returning unsupported
                 attributes and values.

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             c.  If the Client supplies the attribute and the Printer
                 supports the attribute value, the Printer uses the
                 corresponding decompression algorithm on the Document data.

             d.  If the decompression algorithm fails before the Printer
                 returns an operation response, the Printer MUST reject the
                 request and return the 'client-error-compression-error'
                 status-code.

             e.  If the decompression algorithm fails after the Printer
                 returns an operation response, the Printer MUST abort the
                 Job and add the 'compression-error' value to the Job's
                 "job-state-reasons" attribute.

             f.  If the decompression algorithm succeeds, the Document data
                 MUST then have the format specified by the Job's
                 "document-format" attribute, if supplied (see the
                 "document-format" operation attribute definition below).

          "document-format" (mimeMediaType):

             The Client MAY supply and the Printer MUST support this
             attribute.  The value identifies the format of the supplied
             Document data.  The following cases exist:

             a.  If the Client does not supply this attribute, the Printer
                 assumes that the Document data is in the format defined by
                 the Printer's "document-format-default" attribute (i.e.,
                 the Printer follows the rules below as if the Client
                 supplied the "document-format" attribute with a value equal
                 to the Printer's default value).

             b.  If the Client supplies this attribute but the value is not
                 supported by the Printer, i.e., the value is not one of the
                 values of the Printer's "document-format-supported"
                 attribute, the Printer MUST reject the request and return
                 the 'client-error-document-format-not-supported'
                 status-code.

             c.  If the Client supplies this attribute and its value is
                 'application/octet-stream' (i.e., to be auto-sensed; see
                 Section 5.1.10.1), and the format is not one of the
                 Document formats that the Printer can auto-sense, and this
                 check occurs before the Printer returns an operation
                 response, then the Printer MUST reject the request and
                 return the 'client-error-document-format-not-supported'
                 status-code.

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             d.  If the Client supplies this attribute and the value is
                 supported by the Printer, the Printer is capable of
                 interpreting the Document data.

             e.  If interpretation of the Document data fails before the
                 Printer returns an operation response, the Printer MUST
                 reject the request and return the
                 'client-error-document-format-error' status-code.

             f.  If interpretation of the Document data fails after the
                 Printer returns an operation response, the Printer MUST
                 abort the Job and add the 'document-format-error' value to
                 the Job's "job-state-reasons" attribute.

          "document-natural-language" (naturalLanguage):

             The Client MAY supply and the Printer SHOULD support this
             attribute.  The value specifies the natural language of the
             Document content for those Document formats that require a
             specification of the natural language in order to properly
             image the Document.

          "job-k-octets" (integer(0:MAX)):

             The Client MAY supply and the Printer SHOULD support this
             attribute.  The Client-supplied "job-k-octets" operation
             attribute identifies the total size of the Document(s) in
             K octets being submitted (see Section 5.3.17.1 for the complete
             semantics).  If the Client supplies the attribute and the
             Printer supports the attribute, the value of the attribute is
             used to populate the Job's "job-k-octets" Job Description
             attribute.

             For this attribute and the following two attributes
             ("job-impressions" and "job-media-sheets"), if the Client
             supplies the attribute but the Printer does not support the
             attribute, the Printer ignores the Client-supplied value.  If
             the Client supplies the attribute and the Printer supports the
             attribute, and the value is within the range of the
             corresponding Printer's "xxx-supported" attribute, the Printer
             MUST use the value to populate the Job's "xxx" attribute.  If
             the Client supplies the attribute and the Printer supports the
             attribute, but the value is outside the range of the
             corresponding Printer's "xxx-supported" attribute, the Printer
             MUST copy the attribute and its value to the Unsupported
             Attributes group, reject the request, and return the
             'client-error-attributes-or-values-not-supported' status-code.
             If the Client does not supply the attribute, the Printer SHOULD

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             populate the corresponding Job attribute if it supports the
             attribute and is able to calculate or discern the correct
             value.

          "job-impressions" (integer(0:MAX)):

             The Client MAY supply and the Printer SHOULD support this
             attribute.  The Client-supplied "job-impressions" operation
             attribute identifies the total size in number of Impressions of
             the Document(s) being submitted (see Section 5.3.17.2 for the
             complete semantics).

             See the last paragraph under "job-k-octets".

          "job-media-sheets" (integer(1:MAX)):

             The Client MAY supply and the Printer SHOULD support this
             attribute.  The Client-supplied "job-media-sheets" operation
             attribute identifies the total number of Media Sheets to be
             produced for this Job (see Section 5.3.17.3 for the complete
             semantics).

             See the last paragraph under "job-k-octets".

       Group 2: Job Template Attributes

          The Client MAY supply a set of Job Template attributes as defined
          in Section 5.2.  If the Client is not supplying any Job Template
          attributes in the request, the Client SHOULD omit Group 2 rather
          than sending an empty group.  However, a Printer MUST be able to
          accept an empty group.

       Group 3: Document Data

          The Client MUST supply the Document data to be processed.

       The simplest Print-Job request consists of just the
       "attributes-charset" and "attributes-natural-language" operation
       attributes, the "printer-uri" target operation attribute, and the
       Document data.  In this simple case, the Printer:

       o  creates a new Job containing a single Document,

       o  stores a generated Job name in the "job-name" attribute in the
          natural language and charset requested (see Section 4.1.4.1) (if
          those are supported; otherwise, using the Printer's default
          natural language and charset), and

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       o  at Job processing time, uses its corresponding default value
          attributes for the supported Job Template attributes that were not
          supplied by the Client as an IPP attribute or embedded
          instructions in the Document data.

    4.2.1.2.  Print-Job Response

       The Printer MUST return to the Client the following sets of
       attributes as part of the Print-Job response:

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.2.

          Status Message:

             In addition to the REQUIRED status-code returned in every
             response, the response MAY include a "status-message"
             (text(255)) and/or a "detailed-status-message" (text(MAX))
             operation attribute as described in Appendix B and
             Section 4.1.6.  If the Client supplies unsupported or
             conflicting Job Template attributes or values, the Printer MUST
             reject or accept the Print-Job request, depending on whether
             the Client supplied a 'true' or 'false' value for the
             "ipp-attribute-fidelity" operation attribute.  See the
             Implementor's Guides [RFC3196] [PWG5100.19] for guidance on
             processing Job Creation requests.

       Group 2: Unsupported Attributes

          See Section 4.1.7 for details on returning unsupported attributes.

          The value of "ipp-attribute-fidelity" supplied by the Client does
          not affect what attributes the Printer returns in this group.  The
          value of "ipp-attribute-fidelity" only affects whether the
          Print-Job operation is accepted or rejected.  If the Job is
          accepted, the Client can query the Job using the
          Get-Job-Attributes operation, requesting the unsupported
          attributes that were returned in the Print-Job response to see
          which attributes were ignored (not stored in the Job) and which
          attributes were stored with other (substituted) values.

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       Group 3: Job Attributes

          "job-id" (integer(1:MAX)):

             The Printer MUST return the Job's ID in the REQUIRED "job-id"
             Job attribute.  The Client uses this "job-id" attribute in
             conjunction with the "printer-uri" attribute used in the
             Print-Job request when directing Job operations at the Printer.

          "job-uri" (uri):

             The Printer MUST return the Job's URI by returning the contents
             of the REQUIRED "job-uri" Job attribute.

          "job-state" (type1 enum):

             The Printer MUST return the Job's REQUIRED "job-state"
             attribute.  The value of this attribute along with the value of
             the "job-state-reasons" attribute is a "snapshot" of the new
             Job's state when the Printer returns the response.

          "job-state-reasons" (1setOf type2 keyword):

             The Printer MUST return the Job's REQUIRED "job-state-reasons"
             attribute.

          "job-state-message" (text(MAX)):

             The Printer SHOULD return the Job's RECOMMENDED
             "job-state-message" attribute.  If the Printer supports this
             attribute, then it MUST be returned in the response.  If this
             attribute is not returned in the response, the Client can
             assume that the "job-state-message" attribute is not supported
             and will not be returned in a subsequent Job query.

          "number-of-intervening-jobs" (integer(0:MAX)):

             The Printer SHOULD return the Job's RECOMMENDED
             "number-of-intervening-jobs" attribute.  If the Printer
             supports this attribute, then it MUST be returned in the
             response.  If this attribute is not returned in the response,
             the Client can assume that the "number-of-intervening-jobs"
             attribute is not supported and will not be returned in a
             subsequent Job query.

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       Note: Since any Printer state information that affects a Job's state
       is reflected in the "job-state" and "job-state-reasons" attributes,
       it is sufficient to return only these attributes and no additional
       Printer Status attributes.

       Note: The simplest response consists of just the "attributes-charset"
       and "attributes-natural-language" operation attributes and the
       "job-uri", "job-id", and "job-state" Job attributes.  In this
       simplest case, the status-code is 'successful-ok' and there is no
       "status-message" or "detailed-status-message" operation attribute.

    4.2.2.  Print-URI Operation

       This OPTIONAL operation is identical to the Print-Job operation
       (Section 4.2.1), except that a Client supplies a URI reference to the
       Document data using the "document-uri" (uri) operation attribute (in
       Group 1) rather than including the Document data itself.  Before
       returning the response, the Printer MUST validate that the Printer
       supports the retrieval method (e.g., 'http', 'ftp', etc.) implied by
       the URI and MUST check for valid URI syntax.  If the Client-supplied
       URI scheme is not supported, i.e., the value is not in the Printer's
       "referenced-uri-scheme-supported" attribute, the Printer MUST reject
       the request and return the 'client-error-uri-scheme-not-supported'
       status-code.

       The Printer MAY validate the accessibility of the Document as part of
       the operation, or subsequently.  If the Printer discovers an
       accessibility problem before returning an operation response, it MUST
       reject the request and return the
       'client-error-document-access-error' status-code.  The Printer MAY
       also return a specific Document access error code using the
       "document-access-error" operation attribute (see Section 4.1.6.4).

       If the Printer discovers this Document accessibility problem after
       accepting the request and returning an operation response with one of
       the successful status-code values, the Printer MUST add the
       "document-access-error" value to the Job's "job-state-reasons"
       attribute and MAY populate the Job's "job-document-access-errors" Job
       Status attribute (see Section 5.3.11).  See the Implementor's Guides
       [RFC3196] [PWG5100.19] for guidance on processing Job Creation
       requests.

       If the Printer supports this operation, it MUST support the
       "reference-uri-schemes-supported" Printer attribute (see
       Section 5.4.27).

       It is up to the Printer to interpret the URI and subsequently "pull"
       the Document data from the source referenced by the URI string.

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    4.2.3.  Validate-Job Operation

       This REQUIRED operation is similar to the Print-Job operation
       (Section 4.2.1), except that a Client supplies no Document data and
       the Printer allocates no resources, i.e., it does not create a new
       Job.  This operation is used only to verify the capabilities of a
       Printer against whatever attributes are supplied by the Client in the
       Validate-Job request.  By using the Validate-Job operation, a Client
       can validate that an identical Job Creation request (with the
       Document data) would be accepted.  The Validate-Job operation also
       performs the same security negotiation as the Print-Job, Print-URI,
       and Create-Job operations (see Section 9) so that a Client can check
       that the Client and Printer security requirements can be met before
       performing a Job Creation request.

       The Validate-Job operation does not accept a "document-uri" attribute
       in order to allow a Client to check that the same Print-URI operation
       will be accepted, since the Client doesn't send the data with the
       Print-URI operation.  The Client SHOULD just issue the Print-URI
       request.

       The Printer returns the same status-code values, Operation Attributes
       (Group 1), and Unsupported Attributes (Group 2) as the Print-Job
       operation.  However, no Job Attributes (Group 3) are returned, since
       no Job is created.

    4.2.4.  Create-Job Operation

       This RECOMMENDED operation is similar to the Print-Job operation
       (Section 4.2.1), except that in the Create-Job request, a Client does
       not supply Document data or any reference to Document data.  Also,
       the Client does not supply any of the "document-name",
       "document-format", "compression", or "document-natural-language"
       operation attributes.  This operation is followed by one or more
       Send-Document or Send-URI operations.  In each of those operation
       requests, the Client MAY supply the "document-name",
       "document-format", and "document-natural-language" attributes for
       each Document in the Job.

       If a Printer supports the Create-Job operation, it MUST also support
       the Send-Document operation.  If the Printer supports the Create-Job
       and Print-URI operations, it MUST also support the Send-URI
       operation.

       If the Printer supports this operation, it MUST support the
       "multiple-operation-time-out" Printer attribute (see Section 5.4.31).

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       If the Printer supports this operation, then it MUST support the
       "multiple-document-jobs-supported" Printer Description attribute
       (see Section 5.4.16) and indicate whether it supports multiple
       Documents in a Job.

       If the Printer supports this operation and supports multiple
       Documents in a Job, then it MUST support the
       "multiple-document-handling" Job Template attribute with at least
       one value (see Section 5.2.4), and the associated
       "multiple-document-handling-default" and
       "multiple-document-handling-supported" Printer attributes
       (see Section 5.2).

       After the Create-Job operation has completed, the value of the
       "job-state" attribute is similar to the "job-state" after a Print-Job
       operation, even though no Document data has arrived.  A Printer MAY
       set the 'job-data-insufficient' value of the Job's
       "job-state-reasons" attribute to indicate that processing cannot
       begin until sufficient data has arrived and set the "job-state" to
       either 'pending' or 'pending-held'.  A non-spooling Printer that
       doesn't implement the 'pending' Job state can set "job-state" to
       'processing', even though there is not yet any data to process.
       See Sections 5.3.7 and 5.3.8.

    4.2.5.  Get-Printer-Attributes Operation

       This REQUIRED operation allows a Client to request the values of the
       attributes of a Printer.  In the request, the Client supplies the set
       of Printer attribute names and/or attribute group names in which the
       requester is interested.  In the response, the Printer returns a
       corresponding attribute set with the appropriate attribute values
       filled in.

       For Printers, the possible names of attribute groups are:

       o  'job-template': the subset of the Job Template attributes that
          apply to a Printer (the last two columns of Table 8 in
          Section 5.2) that the implementation supports for Printers.

       o  'printer-description': the subset of the attributes specified in
          Section 5.4 that the implementation supports for Printers.

       o  'all': the special group 'all' that includes all attributes that
          the implementation supports for Printers.

       Since a Client MAY request specific attributes or named groups, there
       is a potential for some overlap.  For example, if a Client requests
       'printer-name' and 'all', the Client is actually requesting the

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       "printer-name" attribute twice: once by naming it explicitly, and
       once by inclusion in the 'all' group.  In such cases, the Printer
       returns each attribute only once in the response even if it is
       requested multiple times.  The Client SHOULD NOT request the same
       attribute in multiple ways.

       Printers MUST support all group names and MUST return all supported
       attributes belonging to the group.

    4.2.5.1.  Get-Printer-Attributes Request

       The following sets of attributes are part of the
       Get-Printer-Attributes request:

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.1.

          Target:

             The "printer-uri" (uri) operation attribute, which is the
             target for this operation as described in Section 4.1.5.

          Requesting User Name:

             The "requesting-user-name" (name(MAX)) attribute SHOULD be
             supplied by the Client as described in Section 9.3.

          "requested-attributes" (1setOf keyword):

             The Client MAY supply a set of attribute names and/or attribute
             group names in whose values the requester is interested.  The
             Printer MUST support this attribute.  If the Client omits this
             attribute, the Printer MUST respond as if this attribute had
             been supplied with a value of 'all'.

          "document-format" (mimeMediaType):

             The Client MAY supply and the Printer MUST support this
             attribute.  It is useful for a Client to determine the set of
             supported attribute values that relate to the requested
             Document format.  The Printer MUST return the attributes and
             values that it uses to validate a Job in a Job Creation or
             Validate-Job operation in which this Document format is
             supplied.  The Printer SHOULD return only (1) those attributes

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             that are supported for the specified format and (2) the
             attribute values that are supported for the specified Document
             format.  By specifying the Document format, the Client can get
             the Printer to eliminate the attributes and values that are not
             supported for a specific Document format.  For example, a
             Printer might have multiple interpreters to support both
             'application/postscript' (for PostScript) and 'text/plain' (for
             text) Documents.  However, only one of those interpreters might
             support the "number-up" Job Template attribute with values of
             '1', '2', and '4'.  The other interpreter might only be able to
             support the "number-up" Job Template attribute with a value of
             '1'.  Thus, a Client can use the Get-Printer-Attributes
             operation to obtain the attributes and values that will be used
             to accept/reject a Job Creation request.

             If the Printer does not distinguish between different sets of
             supported values for each different Document format when
             validating Jobs in the Create-Job, Print-Job, Print-URI, and
             Validate-Job operations, it MUST NOT distinguish between
             different Document formats in the Get-Printer-Attributes
             operation.  If the Printer does distinguish between different
             sets of supported values for each different Document format
             specified by the Client, this specialization applies only to
             the following Printer attributes:

             +  Printer attributes that are Job Template attributes
                ("xxx-default", "xxx-supported", and "xxx-ready")
                (see Table 8 in Section 5.2),

             +  "pdl-override-supported",

             +  "compression-supported",

             +  "job-k-octets-supported",

             +  "job-impressions-supported,

             +  "job-media-sheets-supported",

             +  "printer-driver-installer",

             +  "color-supported", and

             +  "reference-uri-schemes-supported"

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             The values of all other Printer attributes (including
             "document-format-supported") remain invariant with respect to
             the Client-supplied Document format (except for new Printer
             Description attributes as registered according to Section 7.2).

             If the Client omits this "document-format" operation attribute,
             the Printer MUST respond as if the attribute had been supplied
             with the value of the Printer's "document-format-default"
             attribute.  Clients SHOULD always supply a value for
             "document-format", since the Printer's
             "document-format-default" value can be
             'application/octet-stream', in which case the returned
             attributes and values are for the union of the Document formats
             that the Printer can automatically sense.  For more details,
             see the description of the 'mimeMediaType' attribute syntax in
             Section 5.1.10.

             If the Client supplies a value for the "document-format"
             operation attribute that is not supported by the Printer, i.e.,
             is not among the values of the Printer's
             "document-format-supported" attribute, the Printer MUST reject
             the operation and return the
             'client-error-document-format-not-supported' status-code.

    4.2.5.2.  Get-Printer-Attributes Response

       The Printer returns the following sets of attributes as part of the
       Get-Printer-Attributes response:

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.2.

          Status Message:

             In addition to the REQUIRED status-code returned in every
             response, the response MAY include a "status-message"
             (text(255)) and/or a "detailed-status-message" (text(MAX))
             operation attribute as described in Appendix B and
             Section 4.1.6.

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       Group 2: Unsupported Attributes

          See Section 4.1.7 for details on returning unsupported attributes.

          The response MAY contain the "requested-attributes" operation
          attribute with any supplied values (attribute keywords) that were
          requested by the Client but are not supported by the Printer.  If
          the Printer does return unsupported attributes referenced in the
          "requested-attributes" operation attribute and that attribute
          included group names, such as 'all', the unsupported attributes
          MUST NOT include attributes described in this document but not
          supported by the implementation.

       Group 3: Printer Attributes

          This is the set of requested attributes and their current values.
          The Printer ignores (does not respond with) any requested
          attribute that is not supported.  The Printer MAY respond with a
          subset of the supported attributes and values, depending on the
          security policy in force.  However, the Printer MUST respond with
          the 'unknown' value for any supported attribute (including all
          REQUIRED attributes) for which the Printer does not know the
          value.  Also, the Printer MUST respond with 'no-value' for any
          supported attribute (including all REQUIRED attributes) for which
          the Administrator has not configured a value.  See the description
          of the "out-of-band" values in the beginning of Section 5.1.

    4.2.6.  Get-Jobs Operation

       This REQUIRED operation allows a Client to retrieve the list of Jobs
       belonging to the target Printer.  The Client can also supply a list
       of Job attribute names and/or attribute group names.  A group of Job
       attributes will be returned for each Job that is returned.

       This operation is similar to the Get-Job-Attributes operation, except
       that this Get-Jobs operation returns attributes from possibly more
       than one Job.

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    4.2.6.1.  Get-Jobs Request

       The Client submits the Get-Jobs request to a Printer.

       The following groups of attributes are part of the Get-Jobs request:

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.1.

          Target:

             The "printer-uri" (uri) operation attribute, which is the
             target for this operation as described in Section 4.1.5.

          Requesting User Name:

             The "requesting-user-name" (name(MAX)) attribute SHOULD be
             supplied by the Client as described in Section 9.3.

          "limit" (integer(1:MAX)):

             The Client MAY supply and the Printer MUST support this
             attribute.  It is an integer value that determines the maximum
             number of Jobs that a Client will receive from the Printer even
             if "which-jobs" or "my-jobs" (described below) constrain which
             Jobs are returned.  The limit is a "stateless limit" in that if
             the value supplied by the Client is 'N', then only the first
             'N' Jobs are returned in the Get-Jobs response.  If the Client
             does not supply this attribute, the Printer responds with all
             applicable Jobs.

          "requested-attributes" (1setOf type2 keyword):

             The Client MAY supply and the Printer MUST support this
             attribute.  It is a set of Job attribute names and/or attribute
             group names in whose values the requester is interested.  This
             set of attributes is returned for each Job that is returned.
             The allowed attribute group names are the same as those defined
             in the Get-Job-Attributes operation in Section 4.3.4.  If the
             Client does not supply this attribute, the Printer MUST respond
             as if the Client had supplied this attribute with two values:
             "job-uri" and "job-id".

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          "which-jobs" (type2 keyword):

             The Client MAY supply and the Printer MUST support this
             attribute.  It indicates which Jobs MUST be returned by the
             Printer.  The values for this attribute include:

             +  'completed': Any Job whose state is 'completed', 'canceled',
                or 'aborted'.

             +  'not-completed': Any Job whose state is 'pending',
                'processing', 'processing-stopped', or 'pending-held'.

             A Printer MUST support both values.  However, if the
             implementation does not keep Jobs in the 'completed',
             'canceled', and 'aborted' states, then it returns no Jobs when
             the 'completed' value is supplied.

             If a Client supplies some other value that is not supported by
             the Printer, the Printer MUST copy the attribute and the
             unsupported value to the Unsupported Attributes group, reject
             the request, and return the
             'client-error-attributes-or-values-not-supported' status-code.

             If the Client does not supply this attribute, the Printer MUST
             respond as if the Client had supplied the attribute with a
             value of 'not-completed'.

          "my-jobs" (boolean):

             The Client MAY supply and the Printer MUST support this
             attribute.  It indicates whether Jobs from all users or just
             the Jobs submitted by the requesting user of this request MUST
             be considered as candidate Jobs to be returned by the Printer.
             If the Client does not supply this attribute, the Printer MUST
             respond as if the Client had supplied the attribute with a
             value of 'false', i.e., Jobs from all users.  The means for
             authenticating the requesting user and matching the Jobs is
             described in Section 9.

    4.2.6.2.  Get-Jobs Response

       The Printer returns all of the Jobs up to the number specified by the
       "limit" attribute that match the criteria as defined by the attribute
       values supplied by the Client in the request.  It is possible that no
       Jobs are returned, since there can literally be no Jobs at the
       Printer or there can be no Jobs that match the criteria supplied by
       the Client.  If the Client requests any Job attributes at all, there
       is a set of Job Attributes returned for each Job.

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       It is not an error for the Printer to return 0 Jobs.  If the response
       returns 0 Jobs because there are no Jobs matching the criteria, and
       the request would have returned one or more Jobs with a status-code
       of 'successful-ok' if there had been Jobs matching the criteria, then
       the status-code for 0 Jobs MUST be 'successful-ok'.

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.2.

          Status Message:

             In addition to the REQUIRED status-code returned in every
             response, the response MAY include a "status-message"
             (text(255)) and/or a "detailed-status-message" (text(MAX))
             operation attribute as described in Appendix B and
             Section 4.1.6.

       Group 2: Unsupported Attributes

          See Section 4.1.7 for details on returning unsupported attributes.

          The response MAY contain the "requested-attributes" operation
          attribute with any supplied values (attribute keywords) that were
          requested by the Client but are not supported by the Printer.  If
          the Printer does return unsupported attributes referenced in the
          "requested-attributes" operation attribute and that attribute
          included group names, such as 'all', the unsupported attributes
          MUST NOT include attributes described in this document but not
          supported by the implementation.

       Groups 3 to N: Job Attributes

          The Printer responds with one set of Job Attributes for each
          returned Job.  The Printer ignores (does not respond with) any
          requested attribute or value that is not supported or that is
          restricted by the security policy in force, including whether the
          requesting user is the user that submitted the Job
          (Job-originating user) or not (see Section 9).  However, the
          Printer MUST respond with the 'unknown' value for any supported
          attribute (including all REQUIRED attributes) for which the
          Printer does not know the value, unless it would violate the
          security policy.  See the description of the "out-of-band" values
          in the beginning of Section 5.1.

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          Jobs are returned in the following order:

          *  If the Client requests all 'completed' Jobs (Jobs in the
             'completed', 'aborted', or 'canceled' states), then the Jobs
             are returned newest to oldest (with respect to actual
             completion time).

          *  If the Client requests all 'not-completed' Jobs (Jobs in the
             'pending', 'processing', 'pending-held', and
             'processing-stopped' states), then Jobs are returned in
             relative chronological order of expected time to complete
             (based on whatever scheduling algorithm is configured for the
             Printer).

    4.2.7.  Pause-Printer Operation

       This OPTIONAL operation allows a Client to stop the Printer from
       scheduling Jobs on all its devices.  Depending on implementation, the
       Pause-Printer operation MAY also stop the Printer from processing the
       current Job or Jobs.  Any Job that is currently being printed is
       either (1) stopped as soon as the implementation permits or
       (2) completed, depending on implementation.  The Printer MUST still
       accept Job Creation requests to create new Jobs but MUST prevent any
       Jobs from entering the 'processing' state.

       If the Pause-Printer operation is supported, then the Resume-Printer
       operation MUST be supported, and vice versa.

       The IPP Printer stops the current Job(s) on its device or devices
       that were in the 'processing' or 'processing-stopped' state as soon
       as the implementation permits.  If the implementation will take
       appreciable time to stop, the IPP Printer adds the 'moving-to-paused'
       value to the Printer's "printer-state-reasons" attribute (see
       Section 5.4.12).  When the device or devices have all stopped, the
       IPP Printer transitions the Printer to the 'stopped' state; removes
       the 'moving-to-paused' value, if present; and adds the 'paused' value
       to the Printer's "printer-state-reasons" attribute.

       When the current Job or Jobs complete that were in the 'processing'
       state, the IPP Printer transitions them to the 'completed' state.
       When the current Job or Jobs stop in mid-processing that were in the
       'processing' state, the IPP Printer transitions them to the
       'processing-stopped' state and adds the 'printer-stopped' value to
       the Jobs' "job-state-reasons" attribute.

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       For any Jobs that are 'pending' or 'pending-held', the
       'printer-stopped' value of the Jobs' "job-state-reasons" attribute
       also applies.  However, the IPP Printer MAY update those Jobs'
       "job-state-reasons" values when those Jobs are queried (so-called
       "lazy evaluation").

       The IPP Printer MUST accept the request in any state and transition
       the Printer to the indicated new "printer-state" before returning, as
       shown in Table 2.

       Access Rights: The authenticated user (see Section 9.3) performing
       this operation MUST be an Operator or Administrator of the Printer
       (see Sections 1 and 9.5).  Otherwise, the IPP Printer MUST reject the
       operation and return 'client-error-forbidden',
       'client-error-not-authenticated', or 'client-error-not-authorized'
       as appropriate.

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       +--------------+--------------+-----------------+-------------------+
       | Current      | New          | "printer-state- | IPP Printer's     |
       | "printer-    | "printer-    | reasons"        | response status-  |
       | state"       | state"       |                 | code and action:  |
       +--------------+--------------+-----------------+-------------------+
       | 'idle'       | 'stopped'    | 'paused'        | 'successful-ok'   |
       +--------------+--------------+-----------------+-------------------+
       | 'processing' | 'processing' | 'moving-to-     | Option 1:         |
       |              |              | paused'         | 'successful-ok';  |
       |              |              |                 | Later, when all   |
       |              |              |                 | output has        |
       |              |              |                 | stopped, the      |
       |              |              |                 | "printer-state"   |
       |              |              |                 | becomes           |
       |              |              |                 | 'stopped', and    |
       |              |              |                 | the 'paused'      |
       |              |              |                 | value replaces    |
       |              |              |                 | the 'moving-to-   |
       |              |              |                 | paused' value in  |
       |              |              |                 | the "printer-     |
       |              |              |                 | state-reasons"    |
       |              |              |                 | attribute         |
       +--------------+--------------+-----------------+-------------------+
       | 'processing' | 'stopped'    | 'paused'        | Option 2:         |
       |              |              |                 | 'successful-ok';  |
       |              |              |                 | all device output |
       |              |              |                 | stopped           |
       |              |              |                 | immediately       |
       +--------------+--------------+-----------------+-------------------+
       | 'stopped'    | 'stopped'    | 'paused'        | 'successful-ok'   |
       +--------------+--------------+-----------------+-------------------+

                     Table 2: Pause-Printer State Transitions

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    4.2.7.1.  Pause-Printer Request

       The following groups of attributes are part of the Pause-Printer
       request:

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.1.

          Target:

             The "printer-uri" (uri) operation attribute, which is the
             target for this operation as described in Section 4.1.5.

          Requesting User Name:

             The "requesting-user-name" (name(MAX)) attribute SHOULD be
             supplied by the Client as described in Section 9.3.

    4.2.7.2.  Pause-Printer Response

       The following groups of attributes are part of the Pause-Printer
       response:

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.2.

          Status Message:

             In addition to the REQUIRED status-code returned in every
             response, the response MAY include a "status-message"
             (text(255)) and/or a "detailed-status-message" (text(MAX))
             operation attribute as described in Appendix B and
             Section 4.1.6.

       Group 2: Unsupported Attributes

          See Section 4.1.7 for details on returning unsupported attributes.

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    4.2.8.  Resume-Printer Operation

       This OPTIONAL operation allows a Client to resume the Printer
       scheduling Jobs on all its devices.  The Printer MUST remove the
       'paused' and 'moving-to-paused' values from the Printer's
       "printer-state-reasons" attribute, if present.  If there are no other
       reasons to keep a device paused (such as a media jam), the IPP
       Printer is free to transition itself to the 'processing' or 'idle'
       state, depending on whether there are Jobs to be processed or not,
       respectively, and the device(s) resumes processing Jobs.

       If the Pause-Printer operation is supported, then the Resume-Printer
       operation MUST be supported, and vice versa.

       The IPP Printer removes the 'printer-stopped' value from any Job's
       "job-state-reasons" attributes contained in that Printer.

       The IPP Printer MUST accept the request in any state and transition
       the Printer to the indicated new state as shown in Table 3.

       Access Rights: The authenticated user (see Section 9.3) performing
       this operation MUST be an Operator or Administrator of the Printer
       (see Sections 1 and 9.5).  Otherwise, the IPP Printer MUST reject the
       operation and return 'client-error-forbidden',
       'client-error-not-authenticated', or 'client-error-not-authorized'
       as appropriate.

       The Resume-Printer request and Resume-Printer response have the same
       attribute groups and attributes as the Pause-Printer operation (see
       Sections 4.2.7.1 and 4.2.7.2).

       +-----------------+-----------------+-------------------------------+
       | Current         | New "printer-   | IPP Printer's response        |
       | "printer-state" | state"          | status-code and action:       |
       +-----------------+-----------------+-------------------------------+
       | 'idle'          | 'idle'          | 'successful-ok'               |
       +-----------------+-----------------+-------------------------------+
       | 'processing'    | 'processing'    | 'successful-ok'               |
       +-----------------+-----------------+-------------------------------+
       | 'stopped'       | 'processing'    | 'successful-ok', when there   |
       |                 |                 | are Jobs to be processed      |
       +-----------------+-----------------+-------------------------------+
       | 'stopped'       | 'idle'          | 'successful-ok', when there   |
       |                 |                 | are no Jobs to be processed   |
       +-----------------+-----------------+-------------------------------+

                     Table 3: Resume-Printer State Transitions

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    4.2.9.  Purge-Jobs Operation

       This DEPRECATED operation allows a Client to remove all Jobs from a
       Printer, regardless of their Job states, including Jobs in the
       Printer's Job History (see Section 5.3.7.2).  After a Purge-Jobs
       operation has been performed, a Printer MUST return no Jobs in
       subsequent Get-Job-Attributes and Get-Jobs responses (until new Jobs
       are submitted).

       Note: This operation SHOULD NOT be supported in new implementations,
       since it destroys Printer accounting information.

       Whether the Purge-Jobs (and Get-Jobs) operation affects Jobs that
       were submitted to the device from sources other than the IPP Printer
       in the same way that the Purge-Jobs operation affects Jobs that were
       submitted to the IPP Printer using IPP depends on implementation,
       i.e., on whether IPP is being used as a universal management protocol
       or just to manage IPP Jobs, respectively.

       Note: If an Operator wants to cancel all Jobs without clearing out
       the Job History, the Operator uses the Cancel-Job operation on each
       Job instead of using the Purge-Jobs operation.

       If this OPTIONAL operation is supported, the Printer MUST accept this
       operation in any state and transition the Printer to the 'idle'
       state.

       Access Rights: The authenticated user (see Section 9.3) performing
       this operation MUST be an Operator or Administrator of the Printer
       (see Sections 1 and 9.5).  Otherwise, the Printer MUST reject the
       operation and return 'client-error-forbidden',
       'client-error-not-authenticated', and 'client-error-not-authorized'
       as appropriate.

       The Purge-Jobs request and Purge-Jobs response have the same
       attribute groups and attributes as the Pause-Printer operation (see
       Sections 4.2.7.1 and 4.2.7.2).

    4.3.  Job Operations

       All Job operations are directed at Jobs.  A Client MUST always supply
       some means of identifying the Job object in order to identify the
       correct target of the operation.  That Job identification SHOULD be
       the combination of a Printer URI with a Job ID but MAY be the
       (single) Job URI.  The IPP implementation MUST support both forms of
       identification for every Job.

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    4.3.1.  Send-Document Operation

       This RECOMMENDED operation allows a Client to add a Document to a Job
       that was created using the Create-Job operation.  In the Create-Job
       response, the Printer returns the Job's URI (the "job-uri" attribute)
       and the Job's 32-bit identifier (the "job-id" attribute).  For each
       new Document that the Client desires to add, the Client uses a
       Send-Document operation.  Each Send-Document request contains the
       entire stream of Document data for one Document.

       If the Printer supports this operation but does not support multiple
       Documents per Job, the Printer MUST reject subsequent Send-Document
       operations supplied with data and return the
       'server-error-multiple-document-jobs-not-supported' status-code.
       However, the Printer MUST accept the first Document with a 'true' or
       'false' value for the "last-document" operation attribute (see
       below), so that Clients MAY always submit one Document Job with a
       'false' value for "last-document" in the first Send-Document and a
       'true' value for "last-document" in the second Send-Document (with
       no data).

       Since the Create-Job and the send operations (Send-Document or
       Send-URI operations) that follow could occur over an arbitrarily long
       period of time for a particular Job, a Client MUST send another send
       operation within a minimum time interval, as defined by the IPP
       Printer, after the receipt of the previous request for the Job.  If a
       Printer supports the Create-Job and Send-Document operations, the
       Printer MUST support the "multiple-operation-time-out" attribute (see
       Section 5.4.31).  This attribute indicates the minimum number of
       seconds the Printer will wait for the next send operation before
       taking some recovery action.

       A Printer MUST recover from an errant Client that does not supply a
       send operation, sometime after the minimum time interval specified by
       the Printer's "multiple-operation-time-out" attribute.  Such recovery
       MAY include any of the following actions or other recovery actions:

       1.  Assume that the Job is an invalid Job, start the process of
           changing the Job state to 'aborted', add the 'aborted-by-system'
           value to the Job's "job-state-reasons" attribute (see
           Section 5.3.8), and clean up all resources associated with the
           Job.  In this case, if another send operation is finally
           received, the Printer responds with a 'client-error-not-possible'
           or 'client-error-not-found' status-code, depending on whether the
           Job is still around when the send operation finally arrives.

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       2.  Assume that the last send operation received was in fact the last
           Document (as if the "last-document" flag had been set to 'true'),
           close the Job, and proceed to process it (i.e., move the Job's
           state to 'pending').

       3.  Assume that the last send operation received was in fact the last
           Document and close the Job, but move it to the 'pending-held'
           state and add the 'submission-interrupted' value to the Job's
           "job-state-reasons" attribute (see Section 5.3.8).  This action
           allows the user or an Operator to determine whether to continue
           processing the Job by moving it back to the 'pending' state using
           the Release-Job operation (see Section 4.3.6) or to cancel the
           Job using the Cancel-Job operation (see Section 4.3.3).

       Each implementation is free to decide the "best" action to take,
       depending on the following: local policy, whether any Documents have
       been added, whether the implementation spools Jobs or not, and/or any
       other piece of information available to it.  If the choice is to
       abort the Job, it is possible that the Job has already been processed
       to the point that some Media Sheet pages have been printed.

       Access Rights: The authenticated user (see Section 9.3) performing
       this operation must be either the Job owner (as determined in the
       Create-Job operation) or an Operator or Administrator of the Printer
       (see Sections 1 and 9.5).  Otherwise, the Printer MUST reject the
       operation and return 'client-error-forbidden',
       'client-error-not-authenticated', or 'client-error-not-authorized'
       as appropriate.

    4.3.1.1.  Send-Document Request

       The following attribute sets are part of the Send-Document request:

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.1.

          Target:

             Either the "printer-uri" (uri) plus "job-id" (integer(1:MAX)),
             or the "job-uri" (uri) operation attribute(s), which define the
             target for this operation as described in Section 4.1.5.

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          Requesting User Name:

             The "requesting-user-name" (name(MAX)) attribute SHOULD be
             supplied by the Client as described in Section 9.3.

          "document-name" (name(MAX)):

             The Client MAY supply and the Printer MUST support this
             attribute.  It contains the Client-supplied Document name.  The
             Document name MAY be different than the Job name and is not
             guaranteed to be unique across multiple Documents in the same
             Job.  Typically, the Client software automatically supplies the
             Document name on behalf of the End User by using a file name or
             an application-generated name.  See the description of the
             "document-name" operation attribute in the Print-Job request
             (Section 4.2.1.1) for more information about this attribute.

          "compression" (type2 keyword):

             See the description of "compression" for the Print-Job
             operation in Section 4.2.1.1.

          "document-format" (mimeMediaType):

             See the description of "document-format" for the Print-Job
             operation in Section 4.2.1.1.

          "document-natural-language" (naturalLanguage):

             The Client MAY supply and the Printer MAY support this
             attribute.  It specifies the natural language of the Document
             content for those Document formats that require a specification
             of the natural language in order to properly image the
             Document.

          "last-document" (boolean):

             The Client MUST supply and the Printer MUST support this
             attribute.  It is a boolean flag that is set to 'true' if this
             is the last Document for the Job; otherwise, it is set to
             'false'.

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       Group 2: Document Data

          The Client MUST supply the Document data if the "last-document"
          flag is set to 'false'.  However, since a Client might not know
          that the previous Document sent with a Send-Document (or Send-URI)
          operation was the last Document (i.e., the "last-document"
          attribute was set to 'false'), it is legal to send a Send-Document
          request with no Document data where the "last-document" flag is
          set to 'true'.  Such a request MUST NOT increment the value of the
          Job's "number-of-documents" attribute, since no real Document was
          added to the Job.  It is not an error for a Client to submit a Job
          with no actual Document data, i.e., only a single Create-Job and
          Send-Document request with a "last-document" operation attribute
          set to 'true' with no Document data.

    4.3.1.2.  Send-Document Response

       The following sets of attributes are part of the Send-Document
       response:

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.2.

          Status Message:

             In addition to the REQUIRED status-code returned in every
             response, the response MAY include a "status-message"
             (text(255)) and/or a "detailed-status-message" (text(MAX))
             operation attribute as described in Appendix B and
             Section 4.1.6.

       Group 2: Unsupported Attributes

          See Section 4.1.7 for details on returning unsupported attributes.

       Group 3: Job Object Attributes

          This is the same set of attributes as those described in the
          Print-Job response (see Section 4.2.1.2).

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    4.3.2.  Send-URI Operation

       This RECOMMENDED operation is identical to the Send-Document
       operation (see Section 4.3.1), except that a Client MUST supply a URI
       reference ("document-uri" operation attribute) rather than the
       Document data itself.  If a Printer supports this operation, Clients
       can use both Send-URI and Send-Document operations to add new
       Documents to an existing Job.  However, if a Client needs to indicate
       that the previous Send-URI or Send-Document was the last Document,
       the Client MUST use the Send-Document operation with no Document data
       and the "last-document" flag set to 'true' (rather than using a
       Send-URI operation with no "document-uri" operation attribute).

       If a Printer supports this operation, it MUST also support the
       Print-URI operation (see Section 4.2.2).

       The Printer MUST validate the syntax and URI scheme of the supplied
       URI before returning a response, just as in the Print-URI operation.
       The Printer MAY validate the accessibility of the Document as part of
       the operation, or subsequently (see Section 4.2.2).

    4.3.3.  Cancel-Job Operation

       This REQUIRED operation allows a Client to cancel a Print Job from
       the time the Job is created up to the time it is completed, canceled,
       or aborted.  Since a Job might already be printing by the time a
       Cancel-Job is received, some Media Sheet pages might be printed
       before the Job is actually terminated.

       The Printer MUST accept or reject the request based on the Job's
       current state and transition the Job to the indicated new state as
       shown in Table 4.

       Access Rights: The authenticated user (see Section 9.3) performing
       this operation must be either the Job owner or an Operator or
       Administrator of the Printer (see Sections 1 and 9.5).  Otherwise,
       the Printer MUST reject the operation and return
       'client-error-forbidden', 'client-error-not-authenticated', or
       'client-error-not-authorized' as appropriate.

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       +-------------------+--------------------+--------------------------+
       | Current "job-     | New "job-state"    | Printer's response       |
       | state"            |                    | status-code and action:  |
       +-------------------+--------------------+--------------------------+
       | 'pending'         | 'canceled'         | 'successful-ok'          |
       +-------------------+--------------------+--------------------------+
       | 'pending-held'    | 'canceled'         | 'successful-ok'          |
       +-------------------+--------------------+--------------------------+
       | 'processing'      | 'canceled'         | 'successful-ok'          |
       +-------------------+--------------------+--------------------------+
       | 'processing'      | 'processing'       | 'successful-ok' (note 1) |
       +-------------------+--------------------+--------------------------+
       | 'processing'      | 'processing'       | 'client-error-not-       |
       |                   |                    | possible' (note 2)       |
       +-------------------+--------------------+--------------------------+
       | 'processing-      | 'canceled'         | 'successful-ok'          |
       | stopped'          |                    |                          |
       +-------------------+--------------------+--------------------------+
       | 'processing-      | 'processing-       | 'successful-ok' (note 1) |
       | stopped'          | stopped'           |                          |
       +-------------------+--------------------+--------------------------+
       | 'processing-      | 'processing-       | 'client-error-not-       |
       | stopped'          | stopped'           | possible' (note 2)       |
       +-------------------+--------------------+--------------------------+
       | 'completed'       | 'completed'        | 'client-error-not-       |
       |                   |                    | possible'                |
       +-------------------+--------------------+--------------------------+
       | 'canceled'        | 'canceled'         | 'client-error-not-       |
       |                   |                    | possible'                |
       +-------------------+--------------------+--------------------------+
       | 'aborted'         | 'aborted'          | 'client-error-not-       |
       |                   |                    | possible'                |
       +-------------------+--------------------+--------------------------+

                       Table 4: Cancel-Job State Transitions

       Note 1: If the implementation requires some measurable time to cancel
       the Job in the 'processing' or 'processing-stopped' Job state, the
       Printer MUST add the 'processing-to-stop-point' value to the Job's
       "job-state-reasons" attribute and then transition the Job to the
       'canceled' state when the processing ceases (see Section 5.3.8).

       Note 2: If the Job already has the 'processing-to-stop-point' value
       in its "job-state-reasons" attribute, then the Printer MUST reject a
       Cancel-Job operation.

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    4.3.3.1.  Cancel-Job Request

       The following groups of attributes are part of the Cancel-Job
       request:

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.1.

          Target:

             Either the "printer-uri" (uri) plus "job-id" (integer(1:MAX)),
             or the "job-uri" (uri) operation attribute(s), which define the
             target for this operation as described in Section 4.1.5.

          Requesting User Name:

             The "requesting-user-name" (name(MAX)) attribute SHOULD be
             supplied by the Client as described in Section 9.3.

          "message" (text(127)):

             The Client MAY supply and the Printer MAY support this
             attribute.  It is a message to the Operator.  This "message"
             attribute is not the same as the "job-message-from-operator"
             attribute.  That attribute is used to report a message from the
             Operator to the End User that queries that attribute.  This
             "message" operation attribute is used to send a message from
             the Client to the Operator along with the operation request.
             How or where to display this message to the Operator (if
             at all) is an implementation decision.

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    4.3.3.2.  Cancel-Job Response

       The following sets of attributes are part of the Cancel-Job response:

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.2.

          Status Message:

             In addition to the REQUIRED status-code returned in every
             response, the response MAY include a "status-message"
             (text(255)) and/or a "detailed-status-message" (text(MAX))
             operation attribute as described in Appendix B and
             Section 4.1.6.

       Group 2: Unsupported Attributes

          See Section 4.1.7 for details on returning unsupported attributes.

          Once a successful response has been sent, the implementation
          guarantees that the Job will eventually end up in the 'canceled'
          state.  Between the time that the Cancel-Job operation is accepted
          and when the Job enters the 'canceled' job-state (see
          Section 5.3.7), the "job-state-reasons" attribute SHOULD contain
          the 'processing-to-stop-point' value, which indicates to later
          queries that although the Job might still be 'processing' it will
          eventually end up in the 'canceled' state, not the 'completed'
          state.

    4.3.4.  Get-Job-Attributes Operation

       This REQUIRED operation allows a Client to request the values of
       attributes of a Job, and it is almost identical to the
       Get-Printer-Attributes operation (see Section 4.2.5).  The only
       differences are that the operation is directed at a Job rather than a
       Printer, there is no "document-format" operation attribute used when
       querying a Job, and the returned attribute group is a set of Job
       attributes rather than a set of Printer attributes.

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       For Jobs, the possible names of attribute groups are:

       o  'job-template': the subset of the Job Template attributes that
          apply to a Job (the first column of Table 8 in Section 5.2) that
          the implementation supports for Jobs.

       o  'job-description': the subset of the Job Description and Status
          attributes specified in Section 5.3 that the implementation
          supports for Jobs.

       o  'all': the special group 'all' that includes all attributes that
          the implementation supports for Jobs.

       Since a Client MAY request specific attributes or named groups, there
       is a potential for some overlap.  For example, if a Client requests
       'job-name' and 'job-description', the Client is actually requesting
       the "job-name" attribute once by naming it explicitly, and once by
       inclusion in the 'job-description' group.  In such cases, the Printer
       returns the attribute only once in the response even if it is
       requested multiple times.  The Client SHOULD NOT request the same
       attribute in multiple ways.

       Jobs MUST support all group names and MUST return all supported
       attributes belonging to the group.

    4.3.4.1.  Get-Job-Attributes Request

       The following groups of attributes are part of the Get-Job-Attributes
       request when the request is directed at a Job:

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.1.

          Target:

             Either the "printer-uri" (uri) plus "job-id" (integer(1:MAX)),
             or the "job-uri" (uri) operation attribute(s), which define the
             target for this operation as described in Section 4.1.5.

          Requesting User Name:

             The "requesting-user-name" (name(MAX)) attribute SHOULD be
             supplied by the Client as described in Section 9.3.

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          "requested-attributes" (1setOf keyword):

             The Client MAY supply and the Printer MUST support this
             attribute.  It is a set of attribute names and/or attribute
             group names in whose values the requester is interested.  If
             the Client omits this attribute, the Printer MUST respond as if
             this attribute had been supplied with a value of 'all'.

    4.3.4.2.  Get-Job-Attributes Response

       The Printer returns the following sets of attributes as part of the
       Get-Job-Attributes response:

       Group 1: Operation Attributes

          Natural Language and Character Set:

             The "attributes-charset" and "attributes-natural-language"
             attributes as described in Section 4.1.4.2.
             "attributes-natural-language" MAY be the natural language of
             the Job, rather than the one requested.

          Status Message:

             In addition to the REQUIRED status-code returned in every
             response, the response MAY include a "status-message"
             (text(255)) and/or a "detailed-status-message" (text(MAX))
             operation attribute as described in Appendix B and
             Section 4.1.6.

       Group 2: Unsupported Attributes

          See Section 4.1.7 for details on returning unsupported attributes.

          The response MAY contain the "requested-attributes" operation
          attribute with any supplied values (attribute keywords) that were
          requested by the Client but are not supported by the Printer.  If
          the Printer does return unsupported attributes referenced in the
          "requested-attributes" operation attribute and that attribute
          included group names, such as 'all', the unsupported attributes
          MUST NOT include attributes described in this document but not
          supported by the implementation.

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       Group 3: Job Attributes

          This is the set of requested attributes and their current values.
          The Printer ignores (does not respond with) any requested
          attribute or value that is not supported or that is restricted by
          the security policy in force, including whether the requesting
          user is the user that submitted the Job (Job-originating user) or
          not (see Section 9).  However, the Printer MUST respond with the
          'unknown' value for any supported attribute (including all
          REQUIRED attributes) for which the Printer does not know the
          value, unless it would violate the security policy.  See the
          description of the "out-of-band" values in the beginning of
          Section 5.1.

    4.3.5.  Hold-Job Operation

       This OPTIONAL operation allows a Client to hold a pending Job in the
       queue so that it is not eligible for scheduling.  If the Hold-Job
       operation is supported, then the Release-Job operation MUST be
       supported, and vice versa.  The OPTIONAL "job-hold-until" operation
       attribute allows a Client to specify whether to hold the Job
       indefinitely or until a specified time period, if supported.

       The Printer MUST accept or reject the request based on the Job's
       current state and transition the Job to the indicated new state as
       shown in Table 5.

       Note: In order to keep the Hold-Job operation simple, such a request
       is rejected when the Job is in the 'processing' or
       'processing-stopped' state.  If an operation is needed to hold Jobs
       while in either of these states, it will be added as an additional
       operation, rather than overloading the Hold-Job operation.  Then it
       is clear to Clients by querying the Printer's "operations-supported"
       (see Section 5.4.15) and the Job's "job-state" (see Section 5.3.7)
       attributes which operations are possible.

       Access Rights: The authenticated user (see Section 9.3) performing
       this operation must be either the Job owner or an Operator or
       Administrator of the Printer (see Sections 1 and 9.5).  Otherwise,
       the Printer MUST reject the operation and return
       'client-error-forbidden', 'client-error-not-authenticated', or
       'client-error-not-authorized' as appropriate.

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       +-------------------+--------------------+--------------------------+
       | Current "job-     | New "job-state"    | Printer's response       |
       | state"            |                    | status-code and action:  |
       +-------------------+--------------------+--------------------------+
       | 'pending'         | 'pending-held'     | 'successful-ok' (note 1) |
       +-------------------+--------------------+--------------------------+
       | 'pending'         | 'pending'          | 'successful-ok' (note 2) |
       +-------------------+--------------------+--------------------------+
       | 'pending-held'    | 'pending-held'     | 'successful-ok' (note 1) |
       +-------------------+--------------------+--------------------------+
       | 'pending-held'    | 'pending'          | 'successful-ok' (note 2) |
       +-------------------+--------------------+--------------------------+
       | 'processing'      | 'processing'       | 'client-error-not-       |
       |                   |                    | possible'                |
       +-------------------+--------------------+--------------------------+
       | 'processing-      | 'processing-       | 'client-error-not-       |
       | stopped'          | stopped'           | possible'                |
       +-------------------+--------------------+--------------------------+
       | 'completed'       | 'completed'        | 'client-error-not-       |
       |                   |                    | possible'                |
       +-------------------+--------------------+--------------------------+
       | 'canceled'        | 'canceled'         | 'client-error-not-       |
       |                   |                    | possible'                |
       +-------------------+--------------------+--------------------------+
       | 'aborted'         | 'aborted'          | 'client-error-not-       |
       |                   |                    | possible'                |
       +-------------------+--------------------+--------------------------+

                        Table 5: Hold-Job State Transitions

       Note 1: If the implementation supports multiple reasons for a Job to
       be in the 'pending-held' state, the Printer MUST add the
       "job-hold-until-specified" value to the Job's "job-state-reasons"
       attribute.

       Note 2: If the Printer supports the "job-hold-until" operation
       attribute, but the specified time period has already started (or is
       the 'no-hold' value) and there are no other reasons to hold the Job,
       the Printer MUST make the Job be a candidate for processing
       immediately (see Section 5.2.2) by putting the Job in the 'pending'
       state.

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    4.3.5.1.  Hold-Job Request

       The groups and operation attributes are the same as those defined for
       a Cancel-Job request (see Section 4.3.3.1), with the addition of the
       following Group 1 operation attribute:

          "job-hold-until" (type2 keyword | name(MAX)):

          The Client MAY supply and the Printer MUST support this operation
          attribute in a Hold-Job request if it supports the
          "job-hold-until" Job Template attribute in Job Creation requests.
          See Section 5.2.2.  The Printer SHOULD support the
          "job-hold-until" Job Template attribute for use in Job Creation
          requests with at least the 'indefinite' value, if it supports the
          Hold-Job operation.  Otherwise, a Client cannot create a Job and
          hold it immediately (without picking some supported time period in
          the future).

          If supplied and supported as specified in the Printer's
          "job-hold-until-supported" attribute, the Printer copies the
          supplied operation attribute to the Job, replacing the Job's
          previous "job-hold-until" attribute, if present, and makes the Job
          a candidate for scheduling during the supplied named time period.

          If supplied but either the "job-hold-until" operation attribute
          itself or the value supplied is not supported, the Printer accepts
          the request, returns the unsupported attribute or value in the
          Unsupported Attributes group according to Section 4.1.7, returns
          the 'successful-ok-ignored-or-substituted-attributes' status-code,
          and holds the Job indefinitely until a Client performs a
          subsequent Release-Job operation.

          If (1) the Client supplies either a value that specifies a time
          period that has already started or the 'no-hold' value (meaning
          don't hold the Job) and (2) the Printer supports the
          "job-hold-until" operation attribute and there are no other
          reasons to hold the Job, the Printer MUST accept the operation and
          make the Job be a candidate for processing immediately (see
          Section 5.2.2).

          If the Client does not supply a "job-hold-until" operation
          attribute in the request, the Printer MUST populate the Job with a
          "job-hold-until" attribute with the 'indefinite' value (if the
          Printer supports the "job-hold-until" attribute) and hold the Job
          indefinitely, until a Client performs a Release-Job operation.

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    4.3.5.2.  Hold-Job Response

       The groups and attributes are the same as those defined for a
       Cancel-Job response (see Section 4.3.3.2).

    4.3.6.  Release-Job Operation

       This OPTIONAL operation allows a Client to release a previously held
       Job so that it is again eligible for scheduling.  If the Hold-Job
       operation is supported, then the Release-Job operation MUST be
       supported, and vice versa.

       This operation removes the "job-hold-until" Job attribute, if
       present, from the Job that had been supplied in the Create-Job or
       most recent Hold-Job or Restart-Job operation and removes its effect
       on the Job.  The Printer MUST remove the "job-hold-until-specified"
       value from the Job's "job-state-reasons" attribute, if present.  See
       Section 5.3.8.

       The Printer MUST accept or reject the request based on the Job's
       current state and transition the Job to the indicated new state as
       shown in Table 6.

       Access Rights: The authenticated user (see Section 9.3) performing
       this operation must be either the Job owner or an Operator or
       Administrator of the Printer (see Sections 1 and 9.5).  Otherwise,
       the Printer MUST reject the operation and return
       'client-error-forbidden', 'client-error-not-authenticated', or
       'client-error-not-authorized' as appropriate.

       The Release-Job request and Release-Job response have the same
       attribute groups and attributes as the Cancel-Job operation (see
       Sections 4.3.3.1 and 4.3.3.2).

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       +-------------------+--------------------+--------------------------+
       | Current "job-     | New "job-state"    | Printer's response       |
       | state"            |                    | status-code and action:  |
       +-------------------+--------------------+--------------------------+
       | 'pending'         | 'pending'          | 'successful-ok'.  No     |
       |                   |                    | effect on the Job.       |
       +-------------------+--------------------+--------------------------+
       | 'pending-held'    | 'pending-held'     | 'successful-ok' (note 1) |
       +-------------------+--------------------+--------------------------+
       | 'pending-held'    | 'pending'          | 'successful-ok'          |
       +-------------------+--------------------+--------------------------+
       | 'processing'      | 'processing'       | 'successful-ok'.  No     |
       |                   |                    | effect on the Job.       |
       +-------------------+--------------------+--------------------------+
       | 'processing-      | 'processing-       | 'successful-ok'.  No     |
       | stopped'          | stopped'           | effect on the Job.       |
       +-------------------+--------------------+--------------------------+
       | 'completed'       | 'completed'        | 'client-error-not-       |
       |                   |                    | possible'                |
       +-------------------+--------------------+--------------------------+
       | 'canceled'        | 'canceled'         | 'client-error-not-       |
       |                   |                    | possible'                |
       +-------------------+--------------------+--------------------------+
       | 'aborted'         | 'aborted'          | 'client-error-not-       |
       |                   |                    | possible'                |
       +-------------------+--------------------+--------------------------+

                      Table 6: Release-Job State Transitions

       Note 1: If there are other reasons to keep the Job in the
       'pending-held' state, such as 'resources-are-not-ready', the Job
       remains in the 'pending-held' state.  Thus, the 'pending-held' state
       is not just for Jobs that have the "job-hold-until" attribute applied
       to them but is also used for any reason that will keep the Job from
       being a candidate for scheduling and processing, such as
       'resources-are-not-ready'.  See the "job-hold-until" attribute
       (Section 5.2.2).

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    4.3.7.  Restart-Job Operation

       This DEPRECATED operation allows a Client to restart a Job that is
       retained in the queue after processing has completed (see
       Section 5.3.7.2).

       Note: This operation SHOULD NOT be supported in new implementations,
       since it destroys Printer accounting information.  The Resubmit-Job
       operation [PWG5100.11] is the safe replacement for this operation and
       makes a copy of the Job, assigns a new "job-uri" and "job-id" to the
       copy, and resets the Job progress attributes in the new copy only.

       The Restart-Job operation moves the Job to the 'pending' or
       'pending-held' Job state and restarts at the beginning on the same
       Printer with the same attribute values.  If any of the Documents in
       the Job were passed by reference (Print-URI or Send-URI), the Printer
       MUST refetch the data, since the semantics of Restart-Job are to
       repeat all Job processing.  The Job Status attributes that accumulate
       Job progress, such as "job-impressions-completed",
       "job-media-sheets-completed", and "job-k-octets-processed", MUST be
       reset to 0 so that they give an accurate record of the Job from its
       restart point.  The Job MUST continue to use the same "job-uri" and
       "job-id" attribute values.

       The Printer MUST accept or reject the request based on the Job's
       current state and transition the Job to the indicated new state as
       shown in Table 7.

       Note: In order to prevent a user from inadvertently restarting a Job
       in the middle, the Restart-Job request is rejected when the Job is in
       the 'processing' or 'processing-stopped' state.  If in the future an
       operation is needed to hold or restart Jobs while in either of these
       states, it will be added as an additional operation, rather than
       overloading the Restart-Job operation, so that it is clear that the
       user intended that the current Job not be completed.

       Access Rights: The authenticated user (see Section 9.3) performing
       this operation must be either the Job owner or an Operator or
       Administrator of the Printer (see Sections 1 and 9.5).  Otherwise,
       the Printer MUST reject the operation and return
       'client-error-forbidden', 'client-error-not-authenticated', or
       'client-error-not-authorized' as appropriate.

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       +-------------------+--------------------+--------------------------+
       | Current "job-     | New "job-state"    | Printer's response       |
       | state"            |                    | status-code and action:  |
       +-------------------+--------------------+--------------------------+
       | 'pending'         | 'pending'          | 'client-error-not-       |
       |                   |                    | possible'                |
       +-------------------+--------------------+--------------------------+
       | 'pending-held'    | 'pending-held'     | 'client-error-not-       |
       |                   |                    | possible'                |
       +-------------------+--------------------+--------------------------+
       | 'processing'      | 'processing'       | 'client-error-not-       |
       |                   |                    | possible'                |
       +-------------------+--------------------+--------------------------+
       | 'processing-      | 'processing-       | 'client-error-not-       |
       | stopped'          | stopped'           | possible'                |
       +-------------------+--------------------+--------------------------+
       | 'completed'       | 'pending' or       | 'successful-ok' - Job is |
       |                   | 'pending-held'     | started over.            |
       +-------------------+--------------------+--------------------------+
       | 'completed'       | 'completed'        | 'client-error-not-       |
       |                   |                    | possible' - see Rule 1.  |
       +-------------------+--------------------+--------------------------+
       | 'canceled'        | 'pending' or       | 'successful-ok' - Job is |
       |                   | 'pending-held'     | started over.            |
       +-------------------+--------------------+--------------------------+
       | 'canceled'        | 'canceled'         | 'client-error-not-       |
       |                   |                    | possible' - see Rule 1.  |
       +-------------------+--------------------+--------------------------+
       | 'aborted'         | 'pending' or       | 'successful-ok' - Job is |
       |                   | 'pending-held'     | started over.            |
       +-------------------+--------------------+--------------------------+
       | 'aborted'         | 'aborted'          | 'client-error-not-       |
       |                   |                    | possible' - see Rule 1.  |
       +-------------------+--------------------+--------------------------+

                      Table 7: Restart-Job State Transitions

       Rule 1: If the Job Retention Period has expired for the Job in this
       state, then the Printer rejects the operation.  See Section 5.3.7.2.

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    4.3.7.1.  Restart-Job Request

       The groups and attributes are the same as those defined for a
       Cancel-Job request (see Section 4.3.3.1), with the addition of the
       following Group 1 operation attribute:

          "job-hold-until" (type2 keyword | name(MAX)):

          The Client MAY supply and the Printer MUST support this operation
          attribute in a Restart-Job request if it supports the
          "job-hold-until" Job Template attribute in Job Creation requests.
          See Section 5.2.2.

          If supplied and supported as specified in the Printer's
          "job-hold-until-supported" attribute, the Printer copies the
          supplied operation attribute to the Job, replacing the Job's
          previous "job-hold-until" attribute, if present, and makes the Job
          a candidate for scheduling during the supplied named time period.
          See Section 5.2.2.

          If supplied but the value is not supported, the Printer accepts
          the request, returns the unsupported attribute or value in the
          Unsupported Attributes group according to Section 4.1.7, returns
          the 'successful-ok-ignored-or-substituted-attributes' status-code,
          and holds the Job indefinitely until a Client performs a
          subsequent Release-Job operation.

          If supplied but the "job-hold-until" operation attribute itself is
          not supported, the Printer accepts the request, returns the
          unsupported attribute with the out-of-band 'unsupported' value in
          the Unsupported Attributes group according to Section 4.1.7,
          returns the 'successful-ok-ignored-or-substituted-attributes'
          status-code, and restarts the Job, i.e., ignores the
          "job-hold-until" attribute.

          If (1) the Client supplies either a value that specifies a time
          period that has already started or the 'no-hold' value (meaning
          don't hold the Job) and (2) the Printer supports the
          "job-hold-until" operation attribute and there are no other
          reasons to hold the Job, the Printer makes the Job a candidate for
          processing immediately (see Section 5.2.2).

          If the Client does not supply a "job-hold-until" operation
          attribute in the request, the Printer removes the "job-hold-until"
          attribute, if present, from the Job.  If there are no other
          reasons to hold the Job, the Restart-Job operation makes the Job a
          candidate for processing immediately (see Section 5.2.2).

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    4.3.7.2.  Restart-Job Response

       The groups and attributes are the same as those defined for a
       Cancel-Job response (see Section 4.3.3.2).

    5.  Object Attributes

       This section describes the attributes with their corresponding
       attribute syntaxes and values that are part of the IPP Model.  The
       sections below show the objects and their associated attributes that
       are included within the scope of this protocol.  Many of these
       attributes are derived from other relevant documents:

       o  Document Printing Application (DPA) [ISO10175]

       o  Printer MIB v2 [RFC3805]

       Each attribute is uniquely identified in this document using a
       "keyword" (see Section 2.3.7) that is the name of the attribute.  The
       keyword is included in the section title describing that attribute.

       Note: Not only are keywords used to identify attributes, but one of
       the attribute syntaxes described below is "keyword" so that some
       attributes have 'keyword' values.  Therefore, these attributes are
       defined as having an attribute syntax that is a set of keywords.

    5.1.  Attribute Syntaxes

       This section defines the basic attribute syntax types that all
       Clients and IPP objects MUST be able to accept in responses and
       accept in requests, respectively.  Each attribute description in
       Sections 4 and 5 includes in the section title the name of the
       attribute with its syntax(es) in parentheses.  A conforming
       implementation of an attribute MUST include the semantics of the
       attribute syntax(es) so identified.  Section 7.7 describes how the
       protocol can be extended with new attribute syntaxes.

       The attribute syntaxes are specified in the following subsections,
       where the subsection title is the keyword name of the attribute
       syntax inside the single quotes.  In operation requests and
       responses, each attribute value MUST be represented as one of the
       attribute syntaxes specified in the subsection title for the
       attribute.  In addition, the value of an attribute in a response (but
       not in a request) MAY be one of the "out-of-band" values
       (Section 5.1.1) whose special encoding rules are defined in the
       Encoding and Transport document [RFC8010].

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       All attributes in a request MUST have one or more values as defined
       in Sections 5.2, 5.3, and 5.4.  All attributes in a response MUST
       have either (1) one or more values as defined in Sections 5.2, 5.3,
       and 5.4 or (2) a single "out-of-band" value.

       Most attributes are defined to have a single attribute syntax.
       However, a few attributes (e.g., "job-sheet", "media",
       "job-hold-until") are defined to have several attribute syntaxes,
       depending on the value.  These multiple attribute syntaxes are
       separated by the "|" character in the subsection title to indicate
       the choice.  Since each value MUST be tagged as to its attribute
       syntax in the protocol, a single-valued attribute instance can have
       any one of its attribute syntaxes and a multi-valued attribute
       instance can have a mixture of its defined attribute syntaxes.

    5.1.1.  Out-of-Band Values - 'unknown', 'unsupported', and 'no-value'

       This document defines three "out-of-band" values that are used in
       place of an attribute's defined syntax:

       o  'unknown': The attribute is supported by the IPP object, but the
          value is unknown to the IPP object for some reason.  This
          out-of-band value is used for attributes that have an intrinsic,
          physical value that cannot be determined by the IPP object at a
          given time, e.g., sheet count, geo-location, etc.

       o  'unsupported': The attribute is unsupported by the IPP object.
          This value MUST be returned only as the value of an attribute in
          the Unsupported Attributes group.

       o  'no-value': The attribute is supported by the Printer, but the
          Administrator has not yet configured a value.

    5.1.2.  'text'

       A 'text' attribute is an attribute whose value is a sequence of zero
       or more characters encoded in a maximum of 1023 ('MAX') octets.  MAX
       is the maximum length for each value of any 'text' attribute.
       However, if an attribute will always contain values whose maximum
       length is much less than MAX, the definition of that attribute will
       include a qualifier that defines the maximum length for values of
       that attribute.  For example, the "printer-location" attribute is
       specified as "printer-location (text(127))".  In this case, text
       values for "printer-location" MUST NOT exceed 127 octets; if supplied
       with a longer text string via some external interface (other than the
       protocol), implementations are free to truncate to this shorter
       length limitation.

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       In this document, all 'text' attributes are defined using the 'text'
       syntax.  However, 'text' is used only for brevity; the formal
       interpretation of 'text' is 'textWithoutLanguage | textWithLanguage'.
       That is, for any attribute defined in this document using the 'text'
       attribute syntax, all IPP objects and Clients MUST support both the
       'textWithoutLanguage' and 'textWithLanguage' attribute syntaxes.
       However, in actual usage and protocol execution, IPP objects and
       Clients accept and return only one of the two syntaxes per attribute.
       The syntax 'text' never appears "on-the-wire".

       Both 'textWithoutLanguage' and 'textWithLanguage' are needed to
       support the real-world needs of interoperability between sites and
       systems that use different natural languages as the basis for human
       communication.  Generally, one natural language applies to all 'text'
       attributes in a given request or response.  The language is indicated
       by the "attributes-natural-language" operation attribute defined in
       Section 4.1.4 or the "attributes-natural-language" Job attribute
       defined in Section 5.3.20, and there is no need to identify the
       natural language for each text string on a value-by-value basis.  In
       these cases, the attribute syntax 'textWithoutLanguage' is used for
       'text' attributes.  In other cases, the Client needs to supply or the
       Printer needs to return a text value in a natural language that is
       different from the rest of the text values in the request or
       response.  In these cases, the Client or Printer uses the attribute
       syntax 'textWithLanguage' for 'text' attributes (this is the Natural
       Language Override mechanism described in Section 4.1.4).

       The 'textWithoutLanguage' and 'textWithLanguage' attribute syntaxes
       are described in more detail in the following sections.

    5.1.2.1.  'textWithoutLanguage'

       The 'textWithoutLanguage' syntax indicates a value that is a sequence
       of zero or more characters encoded in a maximum of 1023 (MAX) octets.
       Text strings are encoded using the rules of some charset.  The
       Printer MUST support the UTF-8 charset [RFC3629] and MAY support
       additional charsets to represent 'text' values, provided that the
       charsets are registered with IANA [IANA-CS].  See Section 5.1.8 for
       the definition of the 'charset' attribute syntax, including
       restricted semantics and examples of charsets.

    5.1.2.2.  'textWithLanguage'

       The 'textWithLanguage' attribute syntax is a compound attribute
       syntax consisting of two parts: a 'textWithoutLanguage' part encoded
       in a maximum of 1023 (MAX) octets plus an additional
       'naturalLanguage' (see Section 5.1.9) part that overrides the natural
       language in force.  The 'naturalLanguage' part explicitly identifies

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       the natural language that applies to the text part of that value and
       that value alone.  For any given 'text' attribute, the
       'textWithoutLanguage' part is limited to the maximum length defined
       for that 'text' attribute, and the 'naturalLanguage' part is always
       limited to 63 (additional) octets.  Using the 'textWithLanguage'
       attribute syntax rather than the normal 'textWithoutLanguage' syntax
       is the so-called "Natural Language Override mechanism" and MUST be
       supported by all IPP objects and Clients.

       If the attribute is multi-valued (1setOf text), then the
       'textWithLanguage' attribute syntax MUST be used to explicitly
       specify each attribute value whose natural language needs to be
       overridden.  Other values in a multi-valued 'text' attribute in a
       request or a response revert to the natural language of the operation
       attribute.

       In a Job Creation request, the Printer MUST accept and store with the
       Job any natural language in the "attributes-natural-language"
       operation attribute, whether the Printer supports that natural
       language or not.  Furthermore, the Printer MUST accept and store any
       'textWithLanguage' attribute value, whether the Printer supports that
       natural language or not.  These requirements are independent of the
       value of the "ipp-attribute-fidelity" operation attribute that the
       Client MAY supply.

       Example: If the Client supplies the "attributes-natural-language"
       operation attribute with the value 'en' indicating English but the
       value of the "job-name" attribute is in French, the Client MUST use
       the 'textWithLanguage' attribute syntax with the following two
       values:

          'fr': Natural Language Override indicating French

          'Rapport Mensuel': the Job name in French

       See the Encoding and Transport document [RFC8010] for the encoding of
       the two parts and a detailed example of the 'textWithLanguage'
       attribute syntax.

    5.1.3.  'name'

       This syntax type is used for user-friendly strings, such as a Printer
       name, that, for humans, are more meaningful than identifiers.  Names
       are never translated from one natural language to another.  The
       'name' attribute syntax is essentially the same as 'text', including
       the REQUIRED support of UTF-8, except that the sequence of characters
       is limited so that its encoded form MUST NOT exceed 255 (MAX) octets.

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       Also, like 'text', 'name' is really an abbreviated notation for
       either 'nameWithoutLanguage' or 'nameWithLanguage'.  That is, all IPP
       objects and Clients MUST support both the 'nameWithoutLanguage' and
       'nameWithLanguage' attribute syntaxes.  However, in actual usage and
       protocol execution, IPP objects and Clients accept and return only
       one of the two syntaxes per attribute.  The syntax 'name' never
       appears "on-the-wire".

       Only the 'text' and 'name' attribute syntaxes permit the Natural
       Language Override mechanism.

       Some attributes are defined as 'type2 keyword | name'.  These
       attributes support values that are either type2 keywords or names.
       This dual-syntax mechanism enables a site Administrator to extend
       these attributes to legally include values that are locally defined
       by the site Administrator.  Such names are not registered with IANA.

    5.1.3.1.  'nameWithoutLanguage'

       The 'nameWithoutLanguage' syntax indicates a value that is a sequence
       of zero or more characters encoded in a maximum of 255 (MAX) octets.

    5.1.3.2.  'nameWithLanguage'

       The 'nameWithLanguage' attribute syntax is a compound attribute
       syntax consisting of two parts: a 'nameWithoutLanguage' (see
       Section 5.1.3.1) part plus an additional 'naturalLanguage' (see
       Section 5.1.9) part that overrides the natural language in force.
       The 'naturalLanguage' part explicitly identifies the natural language
       that applies to that name value and that name value alone.  For any
       given 'name' attribute, the 'nameWithoutLanguage' part is limited to
       the maximum length defined for that 'name' attribute, and the
       'naturalLanguage' part is always limited to 63 (additional) octets.
       Using the 'nameWithLanguage' attribute syntax rather than the normal
       'nameWithoutLanguage' syntax is the Natural Language Override
       mechanism and MUST be supported by all IPP objects and Clients.

       The 'nameWithLanguage' attribute syntax behaves the same as the
       'textWithLanguage' syntax.  If a name is in a language that is
       different than the rest of the object or operation, then this
       'nameWithLanguage' syntax is used rather than the generic
       'nameWithoutLanguage' syntax.

       If the attribute is multi-valued (1setOf name), then the
       'nameWithLanguage' attribute syntax MUST be used to explicitly
       specify each attribute value whose natural language needs to be

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       overridden.  Other values in a multi-valued 'name' attribute in a
       request or a response revert to the natural language of the operation
       attribute.

       In a Job Creation request, the Printer MUST accept and store with the
       Job any natural language in the "attributes-natural-language"
       operation attribute, whether the Printer supports that natural
       language or not.  Furthermore, the Printer MUST accept and store any
       'nameWithLanguage' attribute value, whether the Printer supports that
       natural language or not.  These requirements are independent of the
       value of the "ipp-attribute-fidelity" operation attribute that the
       Client MAY supply.

       Example: If the Client supplies the "attributes-natural-language"
       operation attribute with the value 'en' indicating English but the
       "printer-name" attribute is in German, the Client MUST use the
       'nameWithLanguage' attribute syntax as follows:

          'de': Natural Language Override indicating German

          'Farbdrucker': the Printer name in German

       See the Encoding and Transport document [RFC8010] for the encoding of
       the two parts and a detailed example of the 'nameWithLanguage'
       attribute syntax.

    5.1.3.3.  Matching 'name' Attribute Values

       For purposes of matching two 'name' attribute values for equality,
       such as in Job validation (where a Client-supplied value for
       attribute "xxx" is checked to see if the value is among the values of
       the Printer's corresponding "xxx-supported" attribute), the following
       match rules apply:

       1.  'keyword' values never match 'name' values.

       2.  'name' ('nameWithoutLanguage' and 'nameWithLanguage') values
           match if (1) the name parts match and (2) the Associated
           Natural Language parts (see Section 4.1.4.1) match.  The matching
           rules are as follows:

           2a.  The name parts match if the two names are identical
                character by character, except that it is RECOMMENDED that
                case be ignored as defined in "i;unicode-casemap - Simple
                Unicode Collation Algorithm" [RFC5051].  For example,
                'Ajax-letter-head-white' MUST match 'Ajax-letter-head-white'
                and SHOULD match 'ajax-letter-head-white' and
                'AJAX-LETTER-HEAD-WHITE'.

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           2b.  The Associated Natural Language parts match if the shorter
                of the two meets the syntactic requirements defined in
                Section 2.1 of RFC 5646 [RFC5646] and matches (byte for
                byte, since IPP language tags are lowercase) with the
                longer.  For example, 'en' matches 'en', 'en-us', and
                'en-gb' but matches neither 'fr' nor 'e'.

    5.1.4.  'keyword'

       The 'keyword' attribute syntax is a sequence of characters, of length
       1 to 255, containing only the US-ASCII [RFC20] encoded values for
       lowercase letters ("a"-"z"), digits ("0"-"9"), hyphen ("-"), dot
       ("."), and underscore ("_").  The first character MUST be a lowercase
       letter.  Furthermore, keywords MUST be in US English.

       This syntax type is used for enumerating semantic identifiers of
       entities in the abstract protocol, i.e., entities identified in this
       document.  Keywords are used as attribute names or values of
       attributes.  Unlike 'text' and 'name' attribute values, 'keyword'
       values MUST NOT use the Natural Language Override mechanism, since
       they MUST always be US-ASCII and US English.

       Keywords are for use in the protocol.  A user interface will likely
       provide a mapping between protocol keywords and displayable
       user-friendly words and phrases that are localized to the natural
       language of the user.  While the keywords specified in this document
       MAY be displayed to users whose natural language is US English, they
       MAY be mapped to other US English words for US English users, since
       the user interface is outside the scope of this document.

       In the definition for each attribute of this syntax type, the full
       set of 'keyword' values being defined for that attribute is listed.
       The IANA IPP registry will always contain the complete and current
       list of 'keyword' values for the attribute.

       When a keyword is used to represent an attribute (its name), it MUST
       be unique within the full scope of all IPP objects and attributes.
       When a keyword is used to represent a value of an attribute, it MUST
       be unique just within the scope of that attribute.  That is, the same
       keyword MUST NOT be used for two different values within the same
       attribute to mean two different semantic ideas.  However, the same
       keyword MAY be used across two or more attributes, representing

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       different semantic ideas for each attribute.  Section 7.3 describes
       how the protocol can be extended with new 'keyword' values.  Examples
       of attribute name keywords are:

          "job-name"

          "attributes-charset"

       Note: This document uses "type1" and "type2" prefixes to the
       "keyword" basic syntax to indicate different levels of review for
       extensions (see Section 7.3).

    5.1.5.  'enum'

       The 'enum' attribute syntax is an enumerated integer value that is in
       the range from 1 to 2**31 - 1 (MAX).  Each value has an associated
       'keyword' name.  In the definition for each attribute of this syntax
       type, the full set of possible values for that attribute is listed.
       This syntax type is used for attributes for which there are enum
       values assigned by other standards, such as SNMP MIBs.  A number of
       attribute enum values in this document are also used for
       corresponding attributes in other standards [RFC3805].  This syntax
       type is not used for attributes to which the Administrator can assign
       values.  Section 7.4 describes how the protocol can be extended with
       new enum values.

       Enum values are for use in the protocol.  A user interface will
       provide a mapping between protocol enum values and displayable
       user-friendly words and phrases that are localized to the natural
       language of the user.  While the enum symbols specified in this
       document MAY be displayed to users whose natural language is
       US English, they MAY be mapped to other US English words for
       US English users, since the user interface is outside the scope of
       this document.

       Note: Some SNMP MIBs use '2' for 'unknown', which corresponds to the
       IPP "out-of-band" value 'unknown'.  See the description of the
       "out-of-band" values at the beginning of Section 5.1.  Therefore,
       attributes of type 'enum' typically start at '3'.

       Note: This document uses "type1" and "type2" prefixes to the "enum"
       basic syntax to indicate different levels of review for extensions
       (see Section 7.4).

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    5.1.6.  'uri'

       The 'uri' attribute syntax is any valid Uniform Resource Identifier
       (URI) [RFC3986].  Most often, URIs are simply Uniform Resource
       Locators (URLs).  The maximum length of URIs used as values of IPP
       attributes is 1023 octets.  Although most other IPP attribute syntax
       types allow for only lowercase values, this attribute syntax type
       conforms to the case-sensitive and case-insensitive rules specified
       in [RFC3986].  See also [RFC3196] for a discussion of case in URIs.

    5.1.7.  'uriScheme'

       The 'uriScheme' attribute syntax is a sequence of characters
       representing a URI scheme according to RFC 3986 [RFC3986].  Though
       RFC 3986 requires that the values be case insensitive, IPP requires
       all lowercase values in IPP attributes, to simplify comparing by IPP
       Clients and Printers.

       Standard values for this syntax type include the following keywords:

       o  'ipp': for IPP schemed URIs, e.g., "ipp://example.com/ipp/..."
          [RFC3510]

       o  'ipps': for IPPS schemed URIs, e.g., "ipps://example.com/ipp/..."
          [RFC7472]

       o  'http': for HTTP schemed URIs, e.g., "http://example.com/path/to/
          filename" [RFC7230]

       o  'https': for HTTPS schemed URIs, e.g.,
          "https://example.com/path/to/filename" [RFC7230]

       o  'ftp': for FTP schemed URIs, e.g., "ftp://example.com/path/to/
          filename" [RFC1738]

       o  'mailto': for SMTP schemed URIs, e.g., "mailto:user@example.com"
          [RFC6068]

       o  'file': for file schemed URIs, e.g., "file:///path/to/filename"
          [RFC1738]

       o  'urn': for Uniform Resource Name schemed URIs, e.g.,
          "urn:uuid:01234567-89ab-cdef-fedc-ba9876543210" [RFC4122]

       A Printer MAY support any URI 'scheme' that has been registered with
       IANA [IANA-MT].  The maximum length of URI 'scheme' values used to
       represent IPP attribute values is 63 octets.

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    5.1.8.  'charset'

       The 'charset' attribute syntax is a standard identifier for a
       charset.  A charset is a coded character set and encoding scheme.
       Charsets are used for labeling certain Document contents, 'text'
       attribute values, and 'name' attribute values.  The syntax and
       semantics of this attribute syntax are specified in RFC 2046
       [RFC2046] and contained in the IANA "Character Sets" registry
       [IANA-CS] according to the IANA procedures [RFC2978].  Though
       RFC 2046 requires that the values be case-insensitive US-ASCII
       [RFC20], IPP requires all lowercase values in IPP attributes, to
       simplify comparing by IPP Clients and Printers.  When a character set
       in the IANA registry has more than one name (alias), the name labeled
       as "(preferred MIME name)", if present, MUST be used.

       The maximum length of 'charset' values used to represent IPP
       attribute values is 63 octets.

       Some examples are:

       o  'utf-8': ISO 10646 Universal Multiple-Octet Coded Character Set
          (UCS) [ISO10646] represented as the UTF-8 [RFC3629] transfer
          encoding scheme in which US-ASCII [RFC20] is a subset charset.

       o  'us-ascii': 7-bit American Standard Code for Information
          Interchange (ASCII) [RFC20].

       o  'iso-8859-1': 8-bit One-Byte Coded Character Set, Latin Alphabet
          No. 1 [ISO8859-1].  That standard defines a coded character set
          that is used by Latin languages in the Western Hemisphere and
          Western Europe.  US-ASCII is a subset charset.

       Some attribute descriptions MAY place additional requirements on
       charset values that can be used, such as REQUIRED values that MUST be
       supported or additional restrictions, such as requiring that the
       charset have US-ASCII as a subset charset.

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    5.1.9.  'naturalLanguage'

       The 'naturalLanguage' attribute syntax is a standard identifier for a
       natural language and, optionally, a country or region.  The values
       for this syntax type are defined by RFC 5646 [RFC5646].  Though
       RFC 5646 requires that the values be case-insensitive US-ASCII, IPP
       requires all lowercase values in IPP attributes, to simplify
       comparing by IPP Clients and Printers.  Examples include:

       o  'en': for English

       o  'en-us': for US English

       o  'fr': for French

       o  'de': for German

       The maximum length of 'naturalLanguage' values used to represent IPP
       attribute values is 63 octets.

       Note: While any standard natural language identifier defined in
       RFC 5646 can be used, Clients typically only support a subset of
       these identifiers.  When comparing two identifiers or performing
       lookups, Printers SHOULD be prepared to match legacy identifiers with
       their corresponding modern equivalents and vice versa.

    5.1.10.  'mimeMediaType'

       The 'mimeMediaType' attribute syntax is the Internet media type
       (sometimes called "MIME type") as defined by RFC 2046 [RFC2046] and
       registered according to the procedures of RFC 6838 [RFC6838] for
       identifying a Document format.  The value MAY include a charset
       parameter, or some other parameter, depending on the specification of
       the media type in the IANA "Media Types" registry [IANA-MT].
       Although most other IPP syntax types allow for only lowercase values,
       this syntax type allows for mixed-case values that are
       case insensitive.

       Examples are:

       o  'text/html': An HTML Document

       o  'text/plain': A plain text Document in US-ASCII (RFC 2046
          indicates that in the absence of the charset parameter MUST mean
          US-ASCII rather than simply unspecified) [RFC2046]

       o  'text/plain; charset = US-ASCII': A plain text Document in
          US-ASCII

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       o  'text/plain; charset = ISO-8859-1': A plain text Document in
          ISO 8859-1 (Latin 1) [ISO8859-1]

       o  'text/plain; charset = utf-8': A plain text Document in ISO 10646
          represented as UTF-8 [RFC3629]

       o  'application/postscript': A PostScript Document [RFC2046]

       o  'application/vnd.hp-PCL': A PCL Document [IANA-MT] (charset escape
          sequence embedded in the Document data)

       o  'application/pdf': Portable Document Format [ISO32000]

       o  'application/octet-stream': Auto-sense - see Section 5.1.10.1

       The maximum length of a 'mimeMediaType' value to represent IPP
       attribute values is 255 octets.

    5.1.10.1.  'application/octet-stream' - Auto-Sensing the Document Format

       One special type is 'application/octet-stream'.  If the Printer
       supports this value, the Printer MUST be capable of auto-sensing the
       format of the Document data using an implementation-dependent method
       that examines some number of octets of the Document data, either as
       part of the Job Creation request and/or at Document processing time.
       During auto-sensing, a Printer can determine that the Document data
       has a format that the Printer doesn't recognize.  If the Printer
       determines this problem before returning an operation response, it
       rejects the request and returns the
       'client-error-document-format-not-supported' status-code.  If the
       Printer determines this problem after accepting the request and
       returning an operation response with one of the successful
       status-code values, the Printer adds the
       'unsupported-document-format' value to the Job's "job-state-reasons"
       attribute.

       If the Printer's default value attribute "document-format-default" is
       set to 'application/octet-stream', the Printer not only supports
       auto-sensing of the Document format but will depend on the result of
       applying its auto-sensing when the Client does not supply the
       "document-format" attribute.  If the Client supplies a Document
       format value, the Printer MUST rely on the supplied attribute, rather
       than trust its auto-sensing algorithm.  To summarize:

       1.  If the Client does not supply a Document format value, the
           Printer MUST rely on its default value setting (which can be
           'application/octet-stream' indicating an auto-sensing mechanism).

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       2.  If the Client supplies a value other than
           'application/octet-stream', the Client is supplying valid
           information about the format of the Document data and the Printer
           MUST trust the Client-supplied value more than the outcome of
           applying an automatic format detection mechanism.  For example,
           the Client can request the printing of a PostScript file as a
           'text/plain' Document.  The Printer MUST print a text
           representation of the PostScript commands rather than interpret
           the stream of PostScript commands and print the result.

       3.  If the Client supplies a value of 'application/octet-stream', the
           Client is indicating that the Printer MUST use its auto-sensing
           mechanism on the Client-supplied Document data whether
           auto-sensing is the Printer's default or not.

       Note: Since the auto-sensing algorithm is probabilistic, if the
       Client requests both auto-sensing ("document-format" set to
       'application/octet-stream') and true fidelity
       ("ipp-attribute-fidelity" set to 'true'), the Printer might not be
       able to guarantee exactly what the End User intended (the
       auto-sensing algorithm might mistake one Document format for
       another), but it is able to guarantee that its auto-sensing mechanism
       will be used.

    5.1.11.  'octetString'

       The 'octetString' attribute syntax is a sequence of octets encoded in
       a maximum of 1023 octets that is indicated in syntax definitions
       using the notation 'octetString(MAX)'.  This syntax type is used for
       opaque data.

    5.1.12.  'boolean'

       The 'boolean' attribute syntax has only two values: 'true' and
       'false'.

    5.1.13.  'integer'

       The 'integer' attribute syntax is an integer value that is in the
       range from -2**31 (MIN) to 2**31 - 1 (MAX).  Each individual
       attribute can specify the range constraint explicitly if the range is
       different from the full range of possible integer values -- for
       example, job-priority (integer(1:100)) for the "job-priority"
       attribute, as shown in the title of Section 5.2.1.  However, the
       enforcement of that additional constraint is up to the IPP objects,
       not the protocol.

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    5.1.14.  'rangeOfInteger'

       The 'rangeOfInteger' attribute syntax is an ordered pair of integers
       that defines an inclusive range of integer values.  The first integer
       specifies the lower bound, and the second specifies the upper bound.
       If a range constraint is specified in the attribute definition, i.e.,
       'rangeOfInteger(X:Y)' indicating X as a minimum value and Y as a
       maximum value, then the constraint applies to both integers.

    5.1.15.  'dateTime'

       The 'dateTime' attribute syntax is a standard, fixed-length, 11-octet
       representation of the "DateAndTime" syntax as defined in RFC 2579
       [RFC2579].  RFC 2579 also identifies an 8-octet representation of a
       "DateAndTime" value, but IPP objects MUST use the 11-octet
       representation.  A user interface will provide a mapping between
       protocol dateTime values and displayable user-friendly words or
       presentation values and phrases that are localized to the natural
       language and date format of the user, including time zone.

    5.1.16.  'resolution'

       The 'resolution' attribute syntax specifies a two-dimensional
       resolution in the indicated units.  It consists of three values: a
       cross-feed direction resolution (positive integer value), a feed
       direction resolution (positive integer value), and a units value.
       The semantics of these three components are taken from the suggested
       values in the Printer MIB [RFC3805].  That is, the cross-feed
       direction resolution component is the same as the
       prtMarkerAddressabilityXFeedDir object in the Printer MIB, the feed
       direction resolution component is the same as the
       prtMarkerAddressabilityFeedDir in the Printer MIB, and the units
       component is the same as the prtMarkerAddressabilityUnit object in
       the Printer MIB (namely, '3' indicates dots per inch and '4'
       indicates dots per centimeter).  All three values MUST be present
       even if the first two values are the same.  For example, '300',
       '600', '3' indicates a 300-dpi cross-feed direction resolution and a
       600-dpi feed direction resolution, since a '3' indicates dots per
       inch (dpi).

    5.1.17.  'collection'

       The 'collection' attribute syntax is a container holding one or more
       named values (i.e., attributes), which are called "member
       attributes".  Each 'collection' attribute definition Document lists
       the mandatory and optional member attributes of each collection
       value.  A collection value is similar to an IPP attribute group in a

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       request or a response, such as the Operation Attributes group -- they
       both consist of a set of attributes.  Collections can also be nested,
       i.e., a collection in a collection.

       A collection value consists of three separate components:

       o  A 'begCollection' value with an optional octet string value
          starting the collection,

       o  Zero or more member attributes defined using a series of unnamed
          values starting with a 'memberAttrName' value that specifies the
          member attribute name, and

       o  An 'endCollection' value with an optional name plus octet string
          value finishing the collection.

    5.1.18.  '1setOf X'

       The '1setOf X' attribute syntax is one or more values of attribute
       syntax type X.  This syntax type is used for multi-valued attributes.
       The syntax type is called '1setOf' rather than just 'setOf' as a
       reminder that the set of values MUST NOT be empty (i.e., a set of
       size 0).  Sets are normally unordered; however, each attribute
       description of this type can specify that the values MUST be in a
       certain order for that attribute.

    5.2.  Job Template Attributes

       Job Template attributes describe Job processing intent.  Clients MAY
       supply (in Job Creation requests) and Printers SHOULD support Job
       Template attributes.  See Section 2.3.11 for a description of support
       for OPTIONAL attributes.

       Job Template attributes conform to the following rules.  For each Job
       Template attribute called "xxx":

       1.  If the Printer supports "xxx", then it MUST support both an
           "xxx-default" attribute (unless there is a "No" in Table 8 below)
           and an "xxx-supported" attribute.  If the Printer doesn't support
           "xxx", then it MUST support neither an "xxx-default" attribute
           nor an "xxx-supported" attribute, and it MUST treat an attribute
           "xxx" supplied by a Client as unsupported.  An attribute "xxx"
           can be supported for some Document formats and not supported for
           other Document formats.  For example, it is expected that a
           Printer would only support "orientation-requested" for some
           Document formats (such as 'text/plain' or 'text/html') but not
           others (such as 'application/postscript').

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       2.  Clients MAY supply "xxx" in a Job Creation request.  If "xxx" is
           supplied, the Client is indicating a desired Job processing
           behavior for this Job.  When "xxx" is not supplied, the Client is
           indicating that the Printer apply its default Job processing
           behavior at Job processing time if the Document content does not
           contain an embedded instruction indicating an xxx-related
           behavior.

           Since an Administrator MAY change the default value attribute
           after a Job has been submitted but before it has been processed,
           the default value used by the Printer at Job processing time can
           be different than the default value in effect at Job submission
           time.

       3.  The "xxx-supported" attribute is a Printer attribute that
           describes which Job processing behaviors are supported by that
           Printer.  A Client can query the Printer to find out what
           xxx-related behaviors are supported by inspecting the returned
           values of the "xxx-supported" attribute.

           Note: The "xxx" in each "xxx-supported" attribute name is
           singular, even though an "xxx-supported" attribute usually has
           more than one value, such as "print-quality-supported", unless
           the "xxx" Job Template attribute is plural, such as "finishings"
           or "sides".  In such cases, the "xxx-supported" attribute names
           are "finishings-supported" and "sides-supported".

       4.  The "xxx-default" default value attribute describes what will be
           done at Job processing time when no other Job processing
           information is supplied by the Client (either explicitly as an
           IPP attribute in the Job Creation request or implicitly as an
           embedded instruction within the Document data).

       If an application wishes to present an End User with a list of
       supported values from which to choose, the application SHOULD query
       the Printer for its supported value attributes.  The application
       SHOULD also query the default value attributes.  If the application
       then limits selectable values to only those values that are
       supported, the application can guarantee that the values supplied by
       the Client in the Job Creation request all fall within the set of
       supported values at the Printer.  When querying the Printer, the
       Client MAY enumerate each attribute by name in the
       Get-Printer-Attributes request, or the Client MAY just name the
       "job-template" group in order to get the complete set of supported
       attributes (both supported and default attributes).

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       The "finishings" attribute is an example of a Job Template attribute.
       It can take on a set of values such as '4' ('staple'), '5' ('punch'),
       and/or '6' ('cover'); see Table 10 in Section 5.2.6.  A Client can
       query the Printer for the "finishings-supported" attribute and the
       "finishings-default" attribute.  The supported attribute contains a
       set of supported values.  The default value attribute contains the
       finishing value(s) that will be used for a new Job if the Client does
       not supply a "finishings" attribute in the Job Creation request and
       the Document data does not contain any corresponding finishing
       instructions.  If the Client does supply the "finishings" attribute
       in the Job Creation request, the Printer validates the value or
       values to make sure that they are a subset of the supported values
       identified in the Printer's "finishings-supported" attribute.  See
       Section 4.1.7.

       Table 8 below summarizes the names and relationships for all Job
       Template attributes.  The first column of the table (labeled "Job
       Attribute") shows the name and syntax for each Job Template attribute
       in the Job.  These are the attributes that can optionally be supplied
       by the Client in a Job Creation request.  The last two columns
       (labeled "Printer: Default Value Attribute" and "Printer: "Supported
       Values" Attribute") show the name and syntax for each Job Template
       attribute in the Printer (the default value attributes and the
       "supported values" attributes).  A "No" in the table means the
       Printer MUST NOT support the attribute (that is, the attribute is
       simply not applicable).  For brevity in the table, the 'text' and
       'name' entries do not show the maximum length for each attribute.

       +------------------+----------------------+-------------------------+
       | Job Attribute    | Printer: Default     | Printer: "Supported     |
       |                  | Value Attribute      | Values" Attribute       |
       +------------------+----------------------+-------------------------+
       | job-priority     | job-priority-default | job-priority-supported  |
       | (integer 1:100)  | (integer 1:100)      | (integer 1:100)         |
       +------------------+----------------------+-------------------------+
       | job-hold-until   | job-hold-until-      | job-hold-until-         |
       | (type2 keyword | | default (type2       | supported (1setOf       |
       | name)            | keyword | name)      | (type2 keyword | name)) |
       +------------------+----------------------+-------------------------+
       | job-sheets       | job-sheets-default   | job-sheets-supported    |
       | (type2 keyword | | (type2 keyword |     | (1setOf (type2 keyword  |
       | name)            | name)                | | name))                |
       +------------------+----------------------+-------------------------+
       | multiple-        | multiple-document-   | multiple-document-      |
       | document-        | handling-default     | handling-supported      |
       | handling (type2  | (type2 keyword)      | (1setOf type2 keyword)  |
       | keyword)         |                      |                         |

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       +------------------+----------------------+-------------------------+
       | copies           | copies-default       | copies-supported        |
       | (integer(1:MAX)) | (integer(1:MAX))     | (rangeOfInteger(1:MAX)) |
       +------------------+----------------------+-------------------------+
       | finishings       | finishings-default   | finishings-supported    |
       | (1setOf type2    | (1setOf type2 enum)  | (1setOf type2 enum)     |
       | enum)            |                      |                         |
       +------------------+----------------------+-------------------------+
       | page-ranges      | No                   | page-ranges-supported   |
       | (1setOf          |                      | (boolean)               |
       | rangeOfInteger   |                      |                         |
       | (1:MAX))         |                      |                         |
       +------------------+----------------------+-------------------------+
       | sides (type2     | sides-default (type2 | sides-supported (1setOf |
       | keyword)         | keyword)             | type2 keyword)          |
       +------------------+----------------------+-------------------------+
       | number-up        | number-up-default    | number-up-supported     |
       | (integer(1:MAX)) | (integer(1:MAX))     | (1setOf                 |
       |                  |                      | (integer(1:MAX) |       |
       |                  |                      | rangeOfInteger(1:MAX))) |
       +------------------+----------------------+-------------------------+
       | orientation-     | orientation-         | orientation-requested-  |
       | requested (type2 | requested-default    | supported (1setOf type2 |
       | enum)            | (type2 enum)         | enum)                   |
       +------------------+----------------------+-------------------------+
       | media (type2     | media-default (type2 | media-supported (1setOf |
       | keyword | name)  | keyword | name)      | (type2 keyword | name)) |
       |                  |                      | media-ready (1setOf     |
       |                  |                      | (type2 keyword | name)) |
       +------------------+----------------------+-------------------------+
       | printer-         | printer-resolution-  | printer-resolution-     |
       | resolution       | default (resolution) | supported (1setOf       |
       | (resolution)     |                      | resolution)             |
       +------------------+----------------------+-------------------------+
       | print-quality    | print-quality-       | print-quality-supported |
       | (type2 enum)     | default (type2 enum) | (1setOf type2 enum)     |
       +------------------+----------------------+-------------------------+

                         Table 8: Job Template Attributes

    5.2.1.  job-priority (integer(1:100))

       This attribute specifies a priority for scheduling the Job.  A higher
       value specifies a higher priority.  The value 1 indicates the lowest
       possible priority.  The value 100 indicates the highest possible
       priority.  Among those Jobs that are ready to print, a Printer MUST
       print all Jobs with a priority value of n before printing those with
       a priority value of n - 1 for all n.

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       If the Printer supports this attribute, it MUST always support the
       full range from 1 to 100.  No administrative restrictions are
       permitted.  This way, an End User can always make full use of the
       entire range with any Printer.  If privileged Jobs are implemented
       outside IPP, they MUST have priorities higher than 100, rather than
       restricting the range available to End Users.

       If the Client does not supply this attribute and this attribute is
       supported by the Printer, the Printer MUST use the value of the
       Printer's "job-priority-default" attribute at Job submission time
       (unlike most Job Template attributes that are used if necessary at
       Job processing time).

       The syntax for the "job-priority-supported" attribute is also
       integer(1:100).  This single integer value indicates the number of
       priority levels supported.  The Printer MUST take the value supplied
       by the Client and map it to the closest integer in a sequence of
       n integer values that are evenly distributed over the range from
       1 to 100 using the formula:

          roundToNearestInt((100x + 50) / n)

       where n is the value of "job-priority-supported" and x ranges from
       0 through (n - 1).

       For example, if n = 1, the sequence of values is 50; if n = 2, the
       sequence of values is 25 and 75; if n = 3, the sequence of values is
       17, 50, and 83; if n = 10, the sequence of values is 5, 15, 25, 35,
       45, 55, 65, 75, 85, and 95; if n = 100, the sequence of values is
       1, 2, 3, ... 100.

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       Table 9 shows how a Printer maps Client-supplied "job-priority"
       values for example values of n.

                     +--------------+-------+-------+--------+
                     | job-priority | n = 1 | n = 2 | n = 10 |
                     +--------------+-------+-------+--------+
                     | 1            | 50    | 17    | 5      |
                     +--------------+-------+-------+--------+
                     | 10           | 50    | 17    | 5      |
                     +--------------+-------+-------+--------+
                     | 20           | 50    | 17    | 15     |
                     +--------------+-------+-------+--------+
                     | 30           | 50    | 17    | 25     |
                     +--------------+-------+-------+--------+
                     | 40           | 50    | 50    | 35     |
                     +--------------+-------+-------+--------+
                     | 50           | 50    | 50    | 45     |
                     +--------------+-------+-------+--------+
                     | 60           | 50    | 50    | 55     |
                     +--------------+-------+-------+--------+
                     | 70           | 50    | 50    | 65     |
                     +--------------+-------+-------+--------+
                     | 80           | 50    | 83    | 75     |
                     +--------------+-------+-------+--------+
                     | 90           | 50    | 83    | 85     |
                     +--------------+-------+-------+--------+
                     | 100          | 50    | 83    | 95     |
                     +--------------+-------+-------+--------+

                          Table 9: "job-priority" Values

    5.2.2.  job-hold-until (type2 keyword | name(MAX))

       This attribute specifies the named time period during which the Job
       MUST become a candidate for printing.

       Standard 'keyword' values for named time periods are:

       o  'no-hold': immediately, if there are no other reasons to hold
          the job

       o  'indefinite': the Job is held indefinitely, until a Client
          performs a Release-Job (Section 4.3.6)

       o  'day-time': during the day

       o  'evening': evening

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       o  'night': night

       o  'weekend': weekend

       o  'second-shift': second shift (after close of business)

       o  'third-shift': third shift (after midnight)

       An Administrator MUST associate allowable print times with a named
       time period (by means outside the scope of this IPP/1.1 document).
       An Administrator is encouraged to pick names that suggest the type of
       time period.  An Administrator MAY define additional values using the
       'name' or 'keyword' attribute syntax, depending on implementation.

       If the value of this attribute specifies a time period that is in the
       future, the Printer SHOULD add the "job-hold-until-specified" value
       to the Job's "job-state-reasons" attribute, MUST move the Job to the
       'pending-held' state, and MUST NOT schedule the Job for printing
       until the specified time period arrives.

       When the specified time period arrives, the Printer MUST remove the
       "job-hold-until-specified" value from the Job's "job-state-reasons"
       attribute, if present.  If there are no other Job state reasons that
       keep the Job in the 'pending-held' state, the Printer MUST consider
       the Job as a candidate for processing by moving the Job to the
       'pending' state.

       If this Job attribute value is the named value 'no-hold' or the
       specified time period has already started, the Job MUST be a
       candidate for processing immediately.

       If the Client does not supply this attribute and this attribute is
       supported by the Printer, the Printer MUST use the value of the
       Printer's "job-hold-until-default" at Job submission time (unlike
       most Job Template attributes that are used if necessary at Job
       processing time).

    5.2.3.  job-sheets (type2 keyword | name(MAX))

       This attribute determines which Job start/end sheet(s), if any, MUST
       be printed with a Job.

       Standard 'keyword' values are:

       o  'none': no Job sheet is printed

       o  'standard': one or more site-specific standard Job sheets are
          printed, e.g., a single start sheet or both start and end sheets

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       An Administrator MAY define additional values using the 'name' or
       'keyword' attribute syntax, depending on implementation.

       The effect of this attribute on Jobs with multiple Documents MAY be
       affected by the "multiple-document-handling" Job attribute
       (Section 5.2.4), depending on the Job sheet semantics.

    5.2.4.  multiple-document-handling (type2 keyword)

       This RECOMMENDED attribute controls which Impressions and Media
       Sheets constitute a Set for copy generation and finishing processes.
       When the value of the "copies" attribute exceeds '1', it also
       controls the order in which the copies that result from processing
       the Documents are produced.  For the purposes of this explanation, if
       "a" represents an instance of Document data, then the result of
       processing the data in Document "a" is a sequence of Media Sheets
       represented by "a(*)".  This attribute MUST be supported with at
       least one value if the Printer supports multiple Documents per Job
       (see Sections 4.2.4 and 4.3.1).

       Standard 'keyword' values are:

       o  'single-document': If a Job has multiple Documents, say, the
          Document data is called "a" and "b", then the result of processing
          all the Document data (a and then b) MUST be treated as a single
          sequence of Media Sheets for finishing processes; that is,
          finishing is performed on the concatenation of the sequences
          a(*),b(*).  The Printer MUST NOT force the data in each Document
          instance to be formatted onto a new Impression, nor to start a new
          Impression on a new Media Sheet.  If more than one copy is made,
          the ordering of the sets of Media Sheets resulting from processing
          the Document data MUST be a(*), b(*), a(*), b(*), ..., and the
          Printer MUST force each copy (a(*),b(*)) to start on a new Media
          Sheet.

       o  'separate-documents-uncollated-copies': If a Job has multiple
          Documents, say, the Document data is called "a" and "b", then the
          result of processing the data in each Document instance MUST be
          treated as a single sequence of Media Sheets for finishing
          processes; that is, the sets a(*) and b(*) would each be finished
          separately.  The Printer MUST force each copy of the result of
          processing the data in a single Document to start on a new Media
          Sheet.  If more than one copy is made, the ordering of the sets of
          Media Sheets resulting from processing the Document data MUST be
          a(*), a(*), ..., b(*), b(*), ... .

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       o  'separate-documents-collated-copies': If a Job has multiple
          Documents, say, the Document data is called "a" and "b", then the
          result of processing the data in each Document instance MUST be
          treated as a single sequence of Media Sheets for finishing
          processes; that is, the sets a(*) and b(*) would each be finished
          separately.  The Printer MUST force each copy of the result of
          processing the data in a single Document to start on a new Media
          Sheet.  If more than one copy is made, the ordering of the sets of
          Media Sheets resulting from processing the Document data MUST be
          a(*), b(*), a(*), b(*), ... .

       o  'single-document-new-sheet': Same as 'single-document', except
          that the Printer MUST ensure that the first Impression of each
          Document instance in the Job is placed on a new Media Sheet.  This
          value allows multiple Documents to be stapled together with a
          single staple where each Document starts on a new Media Sheet.

       The 'single-document' value is the same as
       'separate-documents-collated-copies' with respect to the ordering of
       Input Pages, but not Media Sheet generation, since 'single-document'
       will put the first page of the next Document on the back side of a
       Media Sheet if an odd number of pages have been produced so far for
       the Job, while 'separate-documents-collated-copies' always forces the
       next Document or Document copy on to a new Media Sheet.  In addition,
       if the "finishings" attribute specifies 'staple', then with
       'single-document', Documents a and b are stapled together as a single
       Set with no regard to a new Media Sheet, while with
       'single-document-new-sheet', Documents a and b are stapled together
       as a single Set but Document b starts on a new Media Sheet.  With
       'separate-documents-uncollated-copies' and
       'separate-documents-collated-copies', Documents a and b are stapled
       separately.

       Note: The value 'separate-documents-uncollated-copies' produces
       uncollated Media Sheets within a Set, e.g., when "copies" is '2' a
       two-Document Job will be printed as Media Sheets a(1), a(1), a(2),
       a(2), ... a(n), a(n), b(1), b(1), ..., b(n), b(n).  All other values
       produce collated Media Sheets within a Set.

       The relationship of this attribute and the other attributes that
       control Document processing is described in Appendix C.3.

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    5.2.5.  copies (integer(1:MAX))

       This RECOMMENDED attribute specifies the number of copies to be
       printed.

       On many devices, the supported number of collated copies will be
       limited by the number of physical output bins on the device and can
       be different from the number of uncollated copies that can be
       supported.

       Note: The effect of this attribute on Jobs with multiple Documents is
       controlled by the "multiple-document-handling" Job attribute
       (Section 5.2.4).  The relationship of this attribute and the other
       attributes that control Document processing is described in
       Appendix C.3.

    5.2.6.  finishings (1setOf type2 enum)

       This RECOMMENDED attribute identifies the finishing processes that
       the Printer uses for each copy of each printed Document in the Job.
       For Jobs with multiple Documents, the "multiple-document-handling"
       attribute determines what constitutes a "copy" for purposes of
       finishing.

       Standard enum values defined in this document are listed in Table 10.
       The 'staple-xxx' values are specified with respect to the Document as
       if the Document were in portrait orientation with the origin of each
       Media Sheet at the top left corner.  If the Document is actually in
       landscape or reverse-landscape orientation, the Client supplies the
       appropriate transformed value.  For example, to position a staple in
       the upper left-hand corner of a landscape Document when held for
       reading, the Client supplies the 'staple-bottom-left' value, since
       landscape is defined as a +90 degree rotation of the image with
       respect to the media from portrait, i.e., counterclockwise.  On the
       other hand, to position a staple in the upper left-hand corner of a
       reverse-landscape Document when held for reading, the Client supplies
       the 'staple-top-right' value, since reverse-landscape is defined as
       a -90 degree rotation of the image with respect to the media from
       portrait, i.e., clockwise.

       The angle (vertical, horizontal, angled) of each staple with respect
       to the Document depends on the implementation, which can in turn
       depend on the value of the attribute.

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       Note: The effect of this attribute on Jobs with multiple Documents is
       controlled by the "multiple-document-handling" Job attribute
       (Section 5.2.4).  The relationship of this attribute and the other
       attributes that control Document processing is described in
       Appendix C.3.

       Note: The value of '3' ('none') has no effect when combined with any
       other values.

       Note: The "finishings-col" attribute [PWG5100.1] is an alternative to
       the "finishings" attribute that allows the Client to specify
       finishing intent in greater detail.

       +-----------+-------------------------------------------------------+
       | Value     | Symbolic Name and Description                         |
       +-----------+-------------------------------------------------------+
       | '3'       | 'none': Perform no finishing.                         |
       +-----------+-------------------------------------------------------+
       | '4'       | 'staple': Bind the Document(s) with one or more       |
       |           | staples.  The exact number and placement of the       |
       |           | staples are site defined.                             |
       +-----------+-------------------------------------------------------+
       | '5'       | 'punch': This value indicates that holes are required |
       |           | in the finished Document.  The exact number and       |
       |           | placement of the holes are site defined.  The punch   |
       |           | specification MAY be satisfied (in a site-specific    |
       |           | and implementation-specific manner) either by         |
       |           | drilling/punching or by substituting pre-drilled      |
       |           | media.                                                |
       +-----------+-------------------------------------------------------+
       | '6'       | 'cover': This value is specified when it is desired   |
       |           | to select a non-printed (or pre-printed) cover for    |
       |           | the Document.  This does not supplant the             |
       |           | specification of a printed cover (on cover stock      |
       |           | medium) by the Document itself.                       |
       +-----------+-------------------------------------------------------+
       | '7'       | 'bind': This value indicates that a binding is to be  |
       |           | applied to the Document; the type and placement of    |
       |           | the binding are site defined.                         |
       +-----------+-------------------------------------------------------+
       | '8'       | 'saddle-stitch': Bind the Document(s) with one or     |
       |           | more staples (wire stitches) along the middle fold.   |
       |           | The exact number and placement of the staples and the |
       |           | middle fold are implementation defined and/or site    |
       |           | defined.                                              |

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       +-----------+-------------------------------------------------------+
       | '9'       | 'edge-stitch': Bind the Document(s) with one or more  |
       |           | staples (wire stitches) along one edge.  The exact    |
       |           | number and placement of the staples are               |
       |           | implementation defined and/or site defined.           |
       +-----------+-------------------------------------------------------+
       | '10'-'19' | reserved for future generic finishing enum values.    |
       +-----------+-------------------------------------------------------+
       | '20'      | 'staple-top-left': Bind the Document(s) with one or   |
       |           | more staples in the top left corner.                  |
       +-----------+-------------------------------------------------------+
       | '21'      | 'staple-bottom-left': Bind the Document(s) with one   |
       |           | or more staples in the bottom left corner.            |
       +-----------+-------------------------------------------------------+
       | '22'      | 'staple-top-right': Bind the Document(s) with one or  |
       |           | more staples in the top right corner.                 |
       +-----------+-------------------------------------------------------+
       | '23'      | 'staple-bottom-right': Bind the Document(s) with one  |
       |           | or more staples in the bottom right corner.           |
       +-----------+-------------------------------------------------------+
       | '24'      | 'edge-stitch-left': Bind the Document(s) with one or  |
       |           | more staples (wire stitches) along the left edge.     |
       |           | The exact number and placement of the staples are     |
       |           | implementation defined and/or site defined.           |
       +-----------+-------------------------------------------------------+
       | '25'      | 'edge-stitch-top': Bind the Document(s) with one or   |
       |           | more staples (wire stitches) along the top edge.  The |
       |           | exact number and placement of the staples are         |
       |           | implementation defined and/or site defined.           |
       +-----------+-------------------------------------------------------+
       | '26'      | 'edge-stitch-right': Bind the Document(s) with one or |
       |           | more staples (wire stitches) along the right edge.    |
       |           | The exact number and placement of the staples are     |
       |           | implementation defined and/or site defined.           |
       +-----------+-------------------------------------------------------+
       | '27'      | 'edge-stitch-bottom': Bind the Document(s) with one   |
       |           | or more staples (wire stitches) along the bottom      |
       |           | edge.  The exact number and placement of the staples  |
       |           | are implementation defined and/or site defined.       |
       +-----------+-------------------------------------------------------+
       | '28'      | 'staple-dual-left': Bind the Document(s) with two     |
       |           | staples (wire stitches) along the left edge, assuming |
       |           | a portrait Document (see above).                      |

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       +-----------+-------------------------------------------------------+
       | '29'      | 'staple-dual-top': Bind the Document(s) with two      |
       |           | staples (wire stitches) along the top edge, assuming  |
       |           | a portrait Document (see above).                      |
       +-----------+-------------------------------------------------------+
       | '30'      | 'staple-dual-right': Bind the Document(s) with two    |
       |           | staples (wire stitches) along the right edge,         |
       |           | assuming a portrait Document (see above).             |
       +-----------+-------------------------------------------------------+
       | '31'      | 'staple-dual-bottom': Bind the Document(s) with two   |
       |           | staples (wire stitches) along the bottom edge,        |
       |           | assuming a portrait Document (see above).             |
       +-----------+-------------------------------------------------------+

                        Table 10: "finishings" Enum Values

    5.2.7.  page-ranges (1setOf rangeOfInteger(1:MAX))

       This RECOMMENDED attribute identifies the range(s) of Input Pages
       that the Printer uses for each Set to be printed prior to imposition
       of those pages onto Impressions.  Nothing is printed for any pages
       identified that do not exist in the Set/Document(s).  Ranges MUST be
       in ascending order (1-3, 5-7, 15-19, etc.) and MUST NOT overlap so
       that a non-spooling Printer can process the Job in a single pass.  If
       the ranges are not ascending or are overlapping, the Printer MUST
       reject the request and return the 'client-error-bad-request'
       status-code.  The attribute is associated with Input Pages and not
       application-numbered pages such as the page numbers found in the
       headers and/or footers for certain word processing applications.

       For Jobs with multiple Documents, the "multiple-document-handling"
       attribute determines what constitutes a Set for purposes of the
       specified page range(s).  When "multiple-document-handling" is
       'single-document', the Printer MUST apply each supplied page range
       once to the concatenation of the Input Pages.  For example, if there
       are 8 Documents of 10 pages each, the page range '41-60' prints the
       pages in the 5th and 6th Documents as a single Document, and none of
       the pages of the other Documents are printed.  When
       "multiple-document-handling" is
       'separate-documents-uncollated-copies' or
       'separate-documents-collated-copies', the Printer MUST apply each
       supplied page range repeatedly to each Document copy.  For the same
       Job, the page range '1-3, 10-10' would print the first 3 pages
       and the 10th page of each of the 8 Documents in the Job, as 8
       separate Sets.

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       "page-ranges-supported" is a boolean value indicating whether the
       Printer is capable of supporting the printing of page ranges.  This
       capability can differ from one PDL to another.  There is no
       "page-ranges-default" attribute.  If the "page-ranges" attribute is
       not supplied by the Client, all pages of the Document are printed.

       Note: In many cases, the Client supplies only those Input Pages that
       need to be printed in the Document data, and the "page-ranges" Job
       Template attribute is not used.  However, Clients that submit
       already-generated Document data (either static content from some web
       site or previously submitted content the End User wishes to reprint)
       can use this attribute to print just a subset of the pages contained
       in the Document.  In this case, if a "page-ranges" value of 'n-m' is
       specified, the first page to be printed will be page n.  All
       subsequent pages of the Document will be printed through and
       including page m.

       Note: The effect of this attribute on Jobs with multiple Documents is
       controlled by the "multiple-document-handling" Job attribute
       (Section 5.2.4).  The relationship of this attribute and the other
       attributes that control Document processing is described in
       Appendix C.3.

    5.2.8.  sides (type2 keyword)

       This RECOMMENDED attribute specifies how Impressions are placed upon
       the sides of a Media Sheet.

       The standard 'keyword' values are:

       o  'one-sided': imposes each consecutive Impression upon the same
          side of consecutive Media Sheets.

       o  'two-sided-long-edge': imposes each consecutive pair of
          Impressions upon front and back sides of consecutive Media Sheets,
          such that the orientation of each pair of Impressions on the
          medium would be correct for the reader as if for binding on the
          long edge.  This imposition is sometimes called 'duplex' or
          'head-to-head'.

       o  'two-sided-short-edge': imposes each consecutive pair of
          Impressions upon front and back sides of consecutive Media Sheets,
          such that the orientation of each pair of Impressions on the
          medium would be correct for the reader as if for binding on the
          short edge.  This imposition is sometimes called 'tumble' or
          'head-to-toe'.

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       Note: The effect of this attribute on Jobs with multiple Documents is
       controlled by the "multiple-document-handling" Job attribute
       (Section 5.2.4).  The relationship of this attribute and the other
       attributes that control Document processing is described in
       Appendix C.3.

    5.2.9.  number-up (integer(1:MAX))

       This attribute specifies the number of Input Pages to impose upon a
       single Impression.  For example, if the value is:

       o  '1': the Printer MUST place one Input Page on a single Impression.

       o  '2': the Printer MUST place two Input Pages on a single
          Impression.

       o  '4': the Printer MUST place four Input Pages on a single
          Impression.

       In all cases, the Printer MAY add some sort of translation, scaling,
       or rotation of Input Pages when imposing them.

       Note: The effect of this attribute on Jobs with multiple Documents is
       controlled by the "multiple-document-handling" Job attribute
       (Section 5.2.4).  The relationship of this attribute and the other
       attributes that control Document processing is described in
       Appendix C.3.

    5.2.10.  orientation-requested (type2 enum)

       This RECOMMENDED attribute indicates the desired orientation for
       printed Input Pages; it does not describe the orientation of the
       Client-supplied Input Pages.

       For some Document formats (such as 'application/postscript'), the
       desired orientation of the Input Pages is sometimes specified within
       the Document data.  This information is generated by a Printer driver
       prior to the submission of the Print Job.  Other Document formats
       such as 'text/plain' do not include the notion of desired orientation
       within the Document data.  In the latter case, it is possible for the
       Printer to bind the desired orientation to the Document data after it
       has been submitted.  Printers MAY only support
       "orientation-requested" for some Document formats (e.g., 'text/plain'
       or 'text/html') but not others (e.g., 'application/postscript').
       This is no different than any other Job Template attribute, since
       Section 5.2, item 1, points out that a Printer can support or not
       support any Job Template attribute based on the Document format

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       supplied by the Client.  However, a special mention is made here,
       since it is very likely that a Printer will support
       "orientation-requested" for only a subset of the supported Document
       formats.

       Standard enum values are listed in Table 11.

       Note: The effect of this attribute on Jobs with multiple Documents is
       controlled by the "multiple-document-handling" Job attribute
       (Section 5.2.4).  The relationship of this attribute and the other
       attributes that control Document processing is described in
       Appendix C.3.

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       +-------+-----------------------------------------------------------+
       | Value | Symbolic Name and Description                             |
       +-------+-----------------------------------------------------------+
       | '3'   | 'portrait': The content will be imaged across the short   |
       |       | edge of the medium.                                       |
       +-------+-----------------------------------------------------------+
       | '4'   | 'landscape': The content will be imaged across the long   |
       |       | edge of the medium.  Landscape is defined to be a         |
       |       | rotation of the Input Page to be imaged by +90 degrees    |
       |       | with respect to the medium (i.e., counterclockwise) from  |
       |       | the portrait orientation.  Note: The +90 direction was    |
       |       | chosen because simple finishing on the long edge is the   |
       |       | same edge whether portrait or landscape.                  |
       +-------+-----------------------------------------------------------+
       | '5'   | 'reverse-landscape': The content will be imaged across    |
       |       | the long edge of the medium.  Reverse-landscape is        |
       |       | defined to be a rotation of the Input Page to be imaged   |
       |       | by -90 degrees with respect to the medium (i.e.,          |
       |       | clockwise) from the portrait orientation.  Note: The      |
       |       | 'reverse-landscape' value was added because some          |
       |       | applications rotate landscape -90 degrees from portrait,  |
       |       | rather than +90 degrees.                                  |
       +-------+-----------------------------------------------------------+
       | '6'   | 'reverse-portrait': The content will be imaged across the |
       |       | short edge of the medium.  Reverse-portrait is defined to |
       |       | be a rotation of the Input Page to be imaged by 180       |
       |       | degrees with respect to the medium from the portrait      |
       |       | orientation.  Note: The 'reverse-portrait' value was      |
       |       | added for use with the "finishings" attribute in cases    |
       |       | where the opposite edge is desired for finishing a        |
       |       | portrait Document on simple finishing devices that have   |
       |       | only one finishing position.  Thus, a 'text'/plain'       |
       |       | portrait Document can be stapled "on the right" by a      |
       |       | simple finishing device, as is common use with some       |
       |       | Middle Eastern languages such as Hebrew.                  |
       +-------+-----------------------------------------------------------+

                   Table 11: "orientation-requested" Enum Values

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    5.2.11.  media (type2 keyword | name(MAX))

       This RECOMMENDED attribute identifies the medium that the Printer
       uses for all Impressions of the Job.

       The values for "media" historically have included medium names,
       medium sizes, input trays, and electronic forms so that one attribute
       specifies the media.  However, the Client SHOULD only use the media
       attribute to specify medium sizes using PWG Media Standardized Names
       [PWG5101.1].

       If a Printer supports a medium name as a value of this attribute,
       such a medium name implicitly selects an input tray that contains the
       specified medium.  If a Printer supports a medium size as a value of
       this attribute, such a medium size implicitly selects a medium name
       that in turn implicitly selects an input tray that contains the
       medium with the specified size.  If a Printer supports an input tray
       as the value of this attribute, such an input tray implicitly selects
       the medium that is in that input tray at the time the Job prints.
       This case includes manual-feed input trays.  If a Printer supports an
       electronic form as the value of this attribute, such an electronic
       form implicitly selects a medium name that in turn implicitly selects
       an input tray that contains the medium specified by the electronic
       form.  The electronic form also implicitly selects an image that the
       Printer MUST merge with the Document data as it prints each page.

       PWG Media Standardized Names [PWG5101.1] SHOULD be used.  Legacy
       'keyword' values are taken from ISO DPA [ISO10175], the Printer MIB
       [RFC3805], and ASME-Y14.1M [ASME-Y14.1M].  An Administrator MAY
       define additional values using the 'name' or 'keyword' attribute
       syntax, depending on implementation.

       There is also an additional Printer attribute named "media-ready",
       which differs from "media-supported" in that legal values only
       include the subset of "media-supported" values that are physically
       loaded and ready for printing with no Operator intervention required.

       The relationship of this attribute and the other attributes that
       control Document processing is described in Appendix C.3.

       Note: If supported by the Printer, Clients MAY use the alternative
       "media-col" attribute [PWG5100.3] [PWG5100.13] to specify medium
       requirements in greater detail.

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    5.2.12.  printer-resolution (resolution)

       This RECOMMENDED attribute identifies the output resolution that the
       Printer uses for the Job.

       Note: This attribute and the "print-quality" attribute
       (Section 5.2.13) are both used to specify the overall output quality
       of the Job.  If a Client specifies conflicting "printer-resolution"
       and "print-quality" values, Printers SHOULD use the "print-quality"
       value.

    5.2.13.  print-quality (type2 enum)

       This RECOMMENDED attribute specifies the print quality that the
       Printer uses for the Job.

       The standard enum values are listed in Table 12.

       Note: This attribute and the "printer-resolution" attribute
       (Section 5.2.12) are both used to specify the overall output quality
       of the Job.  If a Client specifies conflicting "printer-resolution"
       and "print-quality" values, Printers SHOULD use the "print-quality"
       value.

        +-------+---------------------------------------------------------+
        | Value | Symbolic Name and Description                           |
        +-------+---------------------------------------------------------+
        | '3'   | 'draft': lowest quality available on the Printer        |
        +-------+---------------------------------------------------------+
        | '4'   | 'normal': normal or intermediate quality on the Printer |
        +-------+---------------------------------------------------------+
        | '5'   | 'high': highest quality available on the Printer        |
        +-------+---------------------------------------------------------+

                       Table 12: "print-quality" Enum Values

    5.3.  Job Description and Status Attributes

       The attributes in this section form the attribute group called
       "job-description".  Tables 13 and 14 summarize these attributes.  The
       third column of each table indicates whether the attribute is a
       REQUIRED attribute that MUST be supported by Printers.  If it is not
       indicated as REQUIRED, then it is OPTIONAL.  The maximum size in
       octets for 'text' and 'name' attributes is indicated in parentheses.

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                 +------------------+----------------+-----------+
                 | Attribute        | Syntax         | REQUIRED? |
                 +------------------+----------------+-----------+
                 | job-impressions  | integer(0:MAX) |           |
                 +------------------+----------------+-----------+
                 | job-k-octets     | integer(0:MAX) |           |
                 +------------------+----------------+-----------+
                 | job-media-sheets | integer(1:MAX) |           |
                 +------------------+----------------+-----------+
                 | job-name         | name(MAX)      | REQUIRED  |
                 +------------------+----------------+-----------+

                 Table 13: Job Description Attributes (READ-WRITE)

       +-----------------------------+-------------------------+-----------+
       | Attribute                   | Syntax                  | REQUIRED? |
       +-----------------------------+-------------------------+-----------+
       | attributes-charset          | charset                 | REQUIRED  |
       +-----------------------------+-------------------------+-----------+
       | attributes-natural-language | naturalLanguage         | REQUIRED  |
       +-----------------------------+-------------------------+-----------+
       | date-time-at-completed      | dateTime|unknown|no-    |           |
       |                             | value                   |           |
       +-----------------------------+-------------------------+-----------+
       | date-time-at-creation       | dateTime|unknown        |           |
       +-----------------------------+-------------------------+-----------+
       | date-time-at-processing     | dateTime|unknown|no-    |           |
       |                             | value                   |           |
       +-----------------------------+-------------------------+-----------+
       | job-detailed-status-        | 1setOf text(MAX)        |           |
       | messages                    |                         |           |
       +-----------------------------+-------------------------+-----------+
       | job-document-access-errors  | 1setOf text(MAX)        |           |
       +-----------------------------+-------------------------+-----------+
       | job-id                      | integer(1:MAX)          | REQUIRED  |
       +-----------------------------+-------------------------+-----------+
       | job-impressions-completed   | integer(0:MAX)          |           |
       +-----------------------------+-------------------------+-----------+
       | job-k-octets-processed      | integer(0:MAX)          |           |
       +-----------------------------+-------------------------+-----------+
       | job-media-sheets-completed  | integer(0:MAX)          |           |
       +-----------------------------+-------------------------+-----------+
       | job-message-from-operator   | text(127)               |           |
       +-----------------------------+-------------------------+-----------+
       | job-more-info               | uri                     |           |
       +-----------------------------+-------------------------+-----------+
       | job-originating-user-name   | name(MAX)               | REQUIRED  |

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       +-----------------------------+-------------------------+-----------+
       | job-printer-up-time         | integer(1:MAX)          | REQUIRED  |
       +-----------------------------+-------------------------+-----------+
       | job-printer-uri             | uri                     | REQUIRED  |
       +-----------------------------+-------------------------+-----------+
       | job-state                   | type1 enum              | REQUIRED  |
       +-----------------------------+-------------------------+-----------+
       | job-state-message           | text(MAX)               |           |
       +-----------------------------+-------------------------+-----------+
       | job-state-reasons           | 1setOf type2 keyword    | REQUIRED  |
       +-----------------------------+-------------------------+-----------+
       | job-uri                     | uri                     | REQUIRED  |
       +-----------------------------+-------------------------+-----------+
       | number-of-documents         | integer(0:MAX)          |           |
       +-----------------------------+-------------------------+-----------+
       | number-of-intervening-jobs  | integer(0:MAX)          |           |
       +-----------------------------+-------------------------+-----------+
       | output-device-assigned      | name(127)               |           |
       +-----------------------------+-------------------------+-----------+
       | time-at-completed           | integer(MIN:MAX)        | REQUIRED  |
       +-----------------------------+-------------------------+-----------+
       | time-at-creation            | integer(MIN:MAX)        | REQUIRED  |
       +-----------------------------+-------------------------+-----------+
       | time-at-processing          | integer(MIN:MAX)        | REQUIRED  |
       +-----------------------------+-------------------------+-----------+

                    Table 14: Job Status Attributes (READ-ONLY)

    5.3.1.  job-id (integer(1:MAX))

       This REQUIRED attribute contains the ID of the Job.  The Printer, on
       receipt of a new Job, generates an ID that identifies the new Job on
       that Printer.  The Printer returns the value of the "job-id"
       attribute as part of the response to a Job Creation request.

       For a description of this attribute and its relationship to the
       "job-uri" and "job-printer-uri" attributes, see the discussion in
       Section 3.4 ("Object Identity").

    5.3.2.  job-uri (uri)

       This REQUIRED attribute contains the URI for the Job.  The Printer,
       on receipt of a new Job, generates a URI that identifies the new Job.
       The Printer returns the value of the "job-uri" attribute as part of
       the response to a Job Creation request.  The precise format of a Job
       URI is implementation dependent [RFC3510] [RFC7472].  If the Printer
       supports more than one URI and there is some relationship between the
       newly formed Job URI and the Printer's URI, the Printer uses the

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       Printer URI supplied by the Client in the Job Creation request.  For
       example, if the Job Creation request comes in over a secure channel,
       the new Job URI MUST use the same secure channel.  This can be
       guaranteed because the Printer is responsible for generating the Job
       URI and the Printer is aware of its security configuration and policy
       as well as the Printer URI used in the Job Creation request.

       For a description of this attribute and its relationship to the
       "job-id" and "job-printer-uri" attributes, see the discussion in
       Section 3.4 ("Object Identity").

    5.3.3.  job-printer-uri (uri)

       This REQUIRED attribute identifies the Printer that created this Job.
       When a Printer creates a Job, it populates this attribute with the
       Printer URI that was used in the Job Creation request.  This
       attribute permits a Client to identify the Printer that created this
       Job when only the Job's URI is available to the Client.  The Client
       queries the creating Printer to determine which languages, charsets,
       and operations are supported for this Job.

       For a description of this attribute and its relationship to the
       "job-uri" and "job-id" attributes, see the discussion in Section 3.4
       ("Object Identity").

    5.3.4.  job-more-info (uri)

       Similar to "printer-more-info", this attribute contains the URI
       referencing some resource with more information about this Job,
       perhaps an HTML page containing status information about the Job.

    5.3.5.  job-name (name(MAX))

       This REQUIRED attribute is the name of the Job.  It is a name that is
       more user friendly than the "job-uri" or "job-id" attribute values.
       It does not need to be unique between Jobs.  The Job's "job-name"
       attribute is set to the value supplied by the Client in the
       "job-name" operation attribute in the Job Creation request (see
       Section 4.2.1.1).  If, however, the "job-name" operation attribute is
       not supplied by the Client in the Job Creation request, the Printer,
       on creation of the Job, MUST generate a name.  The Printer SHOULD
       generate the value of the Job's "job-name" attribute from the first
       of the following sources that produces a value: (1) the
       "document-name" operation attribute of the first (or only) Document,
       (2) the "document-URI" attribute of the first (or only) Document, or
       (3) any other piece of Job-specific and/or Document data.

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    5.3.6.  job-originating-user-name (name(MAX))

       This REQUIRED attribute contains the name of the End User that
       submitted the Print Job.  The Printer sets this attribute to the most
       authenticated printable name that it can obtain from the
       authentication service over which the IPP operation was received.
       Only if such a name is not available does the Printer use the value
       supplied by the Client in the "requesting-user-name" operation
       attribute of the Job Creation request (see Sections 5.4.2, 5.4.3,
       and 9).

       Note: The Printer needs to keep an internal originating user ID of
       some form, typically as a credential of a principal, with the Job.
       Since such an internal attribute is implementation dependent and not
       of interest to Clients, it is not specified as a Job attribute.  This
       originating user ID is used for authorization checks (if any) on all
       subsequent operations.

    5.3.7.  job-state (type1 enum)

       This REQUIRED attribute identifies the current state of the Job.
       Even though IPP defines seven values for Job states (plus the
       out-of-band 'unknown' value -- see Section 5.1), implementations only
       need to support those states that are appropriate for the particular
       implementation.  In other words, a Printer supports only those Job
       states implemented by the Output Device and available to the Printer
       implementation.

       Standard enum values are listed in Table 15.

       The final value for this attribute MUST be one of the following --
       'completed', 'canceled', or 'aborted' -- before the Printer removes
       the Job altogether.  The length of time that Jobs remain in the
       'canceled', 'aborted', and 'completed' states depends on
       implementation.  See Section 5.3.7.2.

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       Figure 3 shows the normal Job state transitions.  Normally, a Job
       progresses from left to right.  Other state transitions are unlikely
       but are not forbidden.  Not shown are the transitions to the
       'canceled' state from the 'pending', 'pending-held', and
       'processing-stopped' states.

                                                          +----> canceled
                                                         /
           +----> pending  -------> processing ---------+------> completed
           |         ^                   ^               \
       --->+         |                   |                +----> aborted
           |         v                   v               /
           +----> pending-held    processing-stopped ---+

                           Figure 3: IPP Job Life Cycle

       Jobs reach one of the three terminal states -- 'completed',
       'canceled', or 'aborted' -- after the Jobs have completed all
       activity, including stacking output media, and all Job Status
       attributes have reached their final values for the Job.

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       +--------+----------------------------------------------------------+
       | Values | Symbolic Name and Description                            |
       +--------+----------------------------------------------------------+
       | '3'    | 'pending': The Job is a candidate to start processing    |
       |        | but is not yet processing.                               |
       +--------+----------------------------------------------------------+
       | '4'    | 'pending-held': The Job is not a candidate for           |
       |        | processing for any number of reasons but will return to  |
       |        | the 'pending' state as soon as the reasons are no longer |
       |        | present.  The Job's "job-state-reasons" attribute MUST   |
       |        | indicate why the Job is no longer a candidate for        |
       |        | processing.                                              |
       +--------+----------------------------------------------------------+
       | '5'    | 'processing': One or more of the following: (1) the Job  |
       |        | is using, or is attempting to use, one or more purely    |
       |        | software processes that are analyzing, creating, or      |
       |        | interpreting a PDL, etc.; (2) the Job is using, or is    |
       |        | attempting to use, one or more hardware devices that are |
       |        | interpreting a PDL; making marks on a medium; and/or     |
       |        | performing finishing, such as stapling, etc.; (3) the    |
       |        | Printer has made the Job ready for printing, but the     |
       |        | Output Device is not yet printing it, either because the |
       |        | Job hasn't reached the Output Device or because the Job  |
       |        | is queued in the Output Device or some other spooler,    |
       |        | waiting for the Output Device to print it.  When the Job |
       |        | is in the 'processing' state, the entire Job state       |
       |        | includes the detailed status represented in the          |
       |        | Printer's "printer-state", "printer-state-reasons", and  |
       |        | "printer-state-message" attributes.  Implementations MAY |
       |        | include additional values in the Job's "job-state-       |
       |        | reasons" attribute to indicate the progress of the Job,  |
       |        | such as adding the 'job-printing' value to indicate when |
       |        | the Output Device is actually making marks on paper      |
       |        | and/or the 'processing-to-stop-point' value to indicate  |
       |        | that the Printer is in the process of canceling or       |
       |        | aborting the Job.                                        |

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       +--------+----------------------------------------------------------+
       | '6'    | 'processing-stopped': The Job has stopped while          |
       |        | processing for any number of reasons and will return to  |
       |        | the 'processing' state as soon as the reasons are no     |
       |        | longer present.  The Job's "job-state-reasons" attribute |
       |        | MAY indicate why the Job has stopped processing.  For    |
       |        | example, if the Output Device is stopped, the 'printer-  |
       |        | stopped' value MAY be included in the Job's "job-state-  |
       |        | reasons" attribute.  Note: When an Output Device is      |
       |        | stopped, the device usually indicates its condition in   |
       |        | human-readable form locally at the device.  A Client can |
       |        | obtain more complete device status remotely by querying  |
       |        | the Printer's "printer-state", "printer-state-reasons",  |
       |        | and "printer-state-message" attributes.                  |
       +--------+----------------------------------------------------------+
       | '7'    | 'canceled':  The Job has been canceled by a Cancel-Job   |
       |        | operation, and the Printer has completed canceling the   |
       |        | Job.  All Job Status attributes have reached their final |
       |        | values for the Job.  While the Printer is canceling the  |
       |        | Job, the Job remains in its current state, but the Job's |
       |        | "job-state-reasons" attribute SHOULD contain the         |
       |        | 'processing-to-stop-point' value and one of the          |
       |        | 'canceled-by-user', 'canceled-by-operator', or           |
       |        | 'canceled-at-device' values.  When the Job moves to the  |
       |        | 'canceled' state, the 'processing-to-stop-point' value,  |
       |        | if present, MUST be removed, but 'canceled-by-xxx', if   |
       |        | present, MUST remain.                                    |
       +--------+----------------------------------------------------------+
       | '8'    | 'aborted': The Job has been aborted by the system,       |
       |        | usually while the Job was in the 'processing' or         |
       |        | 'processing-stopped' state, and the Printer has          |
       |        | completed aborting the Job; all Job Status attributes    |
       |        | have reached their final values for the Job.  While the  |
       |        | Printer is aborting the Job, the Job remains in its      |
       |        | current state, but the Job's "job-state-reasons"         |
       |        | attribute SHOULD contain the 'processing-to-stop-point'  |
       |        | and 'aborted-by-system' values.  When the Job moves to   |
       |        | the 'aborted' state, the 'processing-to-stop-point'      |
       |        | value, if present, MUST be removed, but the 'aborted-by- |
       |        | system' value, if present, MUST remain.                  |

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       +--------+----------------------------------------------------------+
       | '9'    | 'completed': The Job has completed successfully or with  |
       |        | warnings or errors after processing, all of the Job      |
       |        | Media Sheets have been successfully stacked in the       |
       |        | appropriate output bin(s), and all Job Status attributes |
       |        | have reached their final values for the Job.  The Job's  |
       |        | "job-state-reasons" attribute SHOULD contain one of the  |
       |        | 'completed-successfully', 'completed-with-warnings', or  |
       |        | 'completed-with-errors' values.                          |
       +--------+----------------------------------------------------------+

                         Table 15: "job-state" Enum Values

    5.3.7.1.  Forwarding Servers

       As with all other IPP attributes, if the implementation cannot
       determine the correct value for this attribute, it SHOULD respond
       with the out-of-band 'unknown' value (see Section 5.1) rather than
       try to guess at some possibly incorrect value and confuse the
       End User about the state of the Job.  For example, if the
       implementation is just a gateway into some printing system from which
       it can normally get status, but temporarily is unable, then the
       implementation should return the 'unknown' value.  However, if the
       implementation is a gateway to a printing system that never provides
       detailed status about the Print Job, the implementation MAY set the
       IPP Job's state to 'completed', provided that it also sets the
       'queued-in-device' value in the Job's "job-state-reasons" attribute
       (see Section 5.3.8).

    5.3.7.2.  Partitioning of Job States

       This section describes the partitioning of the seven Job states into
       phases: Job Not Completed, Job Retention, Job History, and Job
       Removal.  This section also explains the 'job-restartable' value of
       the "job-state-reasons" Job Status attribute for use with the
       Restart-Job and Resubmit-Job [PWG5100.11] operations.

       Job Not Completed: When a Job is in the 'pending', 'pending-held',
       'processing', or 'processing-stopped' state, the Job is not
       completed.

       Job Retention: When a Job enters one of the three terminal Job states
       -- 'completed', 'canceled', or 'aborted' -- the IPP Printer MAY
       "retain" the Job in a restartable condition for an implementation-
       defined time period.  This time period MAY be zero seconds and MAY
       depend on the terminal Job state.  This phase is called "Job
       Retention".  While in the Job Retention phase, the Job's Document
       data is retained and a Client can restart the Job using the

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       Restart-Job operation.  If the Printer supports the Restart-Job or
       Resubmit-Job operation, then it SHOULD indicate that the Job is
       restartable by adding the 'job-restartable' value to the Job's
       "job-state-reasons" attribute (see Section 5.3.8) during the Job
       Retention phase.

       Job History: After the Job Retention phase expires for a Job, the
       Printer deletes the Document data for the Job and the Job becomes
       part of the Job History.  The Printer MAY also delete any number of
       the Job attributes.  Since the Job is no longer restartable, the
       Printer MUST remove the 'job-restartable' value from the Job's
       "job-state-reasons" attribute, if present.  Printers SHOULD keep the
       Job in the Job History phase for at least 60 seconds to allow Clients
       to discover the final disposition of the Job.

       Job Removal: After the Job has remained in the Job History for an
       implementation-defined time, such as when the number of Jobs exceeds
       a fixed number or after a fixed time period (which MAY be
       zero seconds), the IPP Printer removes the Job from the system.

       Using the Get-Jobs operation and supplying the 'not-completed' value
       for the "which-jobs" operation attribute, a Client is requesting Jobs
       in the Job Not Completed phase.  Using the Get-Jobs operation and
       supplying the 'completed' value for the "which-jobs" operation
       attribute, a Client is requesting Jobs in the Job Retention and Job
       History phases.  Using the Get-Job-Attributes operation, a Client is
       requesting a Job in any phase except Job Removal.  After Job Removal,
       the Get-Job-Attributes and Get-Jobs operations no longer are capable
       of returning any information about a Job.

    5.3.8.  job-state-reasons (1setOf type2 keyword)

       This REQUIRED attribute provides additional information about the
       Job's current state, i.e., information that augments the value of the
       Job's "job-state" attribute.

       These values MAY be used with any Job state or states for which the
       reason makes sense.  Some of these value definitions indicate
       conformance requirements; the rest are OPTIONAL.  Furthermore, when
       implemented, the Printer MUST return these values when the reason
       applies and MUST NOT return them when the reason no longer applies,
       whether the value of the Job's "job-state" attribute changed or not.
       When the Job does not have any reasons for being in its current
       state, the value of the Job's "job-state-reasons" attribute MUST be
       'none'.

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       Note: While values cannot be added to the "job-state" attribute
       without impacting deployed Clients that take actions upon receiving
       "job-state" values, it is the intent that additional
       "job-state-reasons" values can be defined and registered without
       impacting such deployed Clients.  In other words, the
       "job-state-reasons" attribute is intended to be extensible.

       The following standard 'keyword' values are defined.  For ease of
       understanding, the values are presented in the order in which the
       reasons are likely to occur (if implemented):

       o  'none': There are no reasons for the Job's current state.  This
          state reason is semantically equivalent to "job-state-reasons"
          without any value and MUST be used when there is no other value,
          since the '1setOf' attribute syntax requires at least one value.

       o  'job-incoming': Either (1) the Printer has accepted the Create-Job
          operation and is expecting additional Send-Document and/or
          Send-URI operations or (2) the Printer is retrieving/accepting
          Document data as a result of a Print-Job, Print-URI,
          Send-Document, or Send-URI operation.

       o  'job-data-insufficient': The Create-Job operation has been
          accepted by the Printer, but the Printer is expecting additional
          Document data before it can move the Job into the 'processing'
          state.  If a Printer starts processing before it has received all
          data, the Printer removes the 'job-data-insufficient' reason, but
          the 'job-incoming' reason remains.  If a Printer starts processing
          after it has received all data, the Printer removes the
          'job-data-insufficient' reason and the 'job-incoming' reason at
          the same time.

       o  'document-access-error': After accepting a Print-URI or Send-URI
          request, the Printer could not access one or more Documents passed
          by reference.  This reason is intended to cover any file access
          problem, including 'file does not exist' and 'access denied'
          because of an access control problem.  The Printer MAY also
          indicate the Document access error using the
          "job-document-access-errors" Job Status attribute (see
          Section 5.3.11).  The Printer can (1) abort the Job and move the
          Job to the 'aborted' Job state or (2) print all Documents that are
          accessible and move the Job to the 'completed' Job state with the
          'completed-with-errors' value in the Job's "job-state-reasons"
          attribute.  This value SHOULD be supported if the Print-URI or
          Send-URI operations are supported.

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       o  'submission-interrupted': The Job was not completely submitted for
          some unforeseen reason, such as (1) the Printer has crashed before
          the Job was closed by the Client, (2) the Printer or the Document
          transfer method has crashed in some non-recoverable way before the
          Document data was entirely transferred to the Printer, or (3) the
          Client crashed or failed to close the Job before the time-out
          period.  See Section 5.4.31.

       o  'job-outgoing': The Printer is transmitting the Job to the Output
          Device.

       o  'job-hold-until-specified': The value of the Job's
          "job-hold-until" attribute was specified with a time period that
          is still in the future.  The Job MUST NOT be a candidate for
          processing until this reason is removed and there are no other
          reasons to hold the Job.  This value SHOULD be supported if the
          "job-hold-until" Job Template attribute is supported.

       o  'resources-are-not-ready': At least one of the resources needed by
          the Job, such as media, fonts, resource objects, etc., is not
          ready on any of the physical Output Devices for which the Job is a
          candidate.  This condition MAY be detected when the Job is
          accepted, or subsequently while the Job is pending or processing,
          depending on implementation.  The Job can remain in its current
          state or be moved to the 'pending-held' state, depending on
          implementation and/or Job scheduling policy.

       o  'printer-stopped-partly': The value of the Printer's
          "printer-state-reasons" attribute contains the value
          'stopped-partly'.

       o  'printer-stopped': The value of the Printer's "printer-state"
          attribute is 'stopped'.

       o  'job-interpreting': The Job is in the 'processing' state, but,
          more specifically, the Printer is interpreting the Document data.

       o  'job-queued': The Job is in the 'processing' state, but, more
          specifically, the Printer has queued the Document data.

       o  'job-transforming': The Job is in the 'processing' state, but,
          more specifically, the Printer is interpreting Document data and
          producing another electronic representation.

       o  'job-queued-for-marker': The Job is in any of the 'pending-held',
          'pending', or 'processing' states, but, more specifically, the
          Printer has completed enough processing of the Document to be able
          to start marking, and the Job is waiting for the marker.  Systems

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          that require human intervention to release Jobs using the
          Release-Job operation put the Job into the 'pending-held' Job
          state.  Systems that automatically select a Job to use the marker
          put the Job into the 'pending' Job state or keep the Job in the
          'processing' Job state while waiting for the marker, depending on
          implementation.  All implementations put the Job into the
          'processing' state when marking does begin.

       o  'job-printing': The Output Device is marking media.  This value is
          useful for Printers that spend a great deal of time processing
          (1) when no marking is happening and they want to show that
          marking is now happening or (2) when the Job is in the process of
          being canceled or aborted while the Job remains in the
          'processing' state, but the marking has not yet stopped so that
          Impression or sheet counts are still increasing for the Job.

       o  'job-canceled-by-user': The Job was canceled by the owner of the
          Job using the Cancel-Job request, i.e., by a user whose
          authenticated identity is the same as the value of the originating
          user that created the Job, or by some other authorized End User,
          such as a member of the Job owner's security group.  This value
          SHOULD be supported.

       o  'job-canceled-by-operator': The Job was canceled by the Operator
          using the Cancel-Job request, i.e., by a user who has been
          authenticated as having Operator privileges (whether local or
          remote).  If the security policy is to allow anyone to cancel
          anyone's Job, then this value can be used when the Job is canceled
          by other than the owner of the Job.  For such a security policy,
          in effect, everyone is an Operator as far as canceling Jobs with
          IPP is concerned.  This value SHOULD be supported if the
          implementation permits canceling by other than the owner of
          the Job.

       o  'job-canceled-at-device': The Job was canceled by an unidentified
          local user, i.e., a user at a console at the device.  This value
          SHOULD be supported if the implementation supports canceling Jobs
          at the console.

       o  'aborted-by-system': The Job (1) is in the process of being
          aborted, (2) has been aborted by the system and placed in the
          'aborted' state, or (3) has been aborted by the system and placed
          in the 'pending-held' state, so that a user or Operator can
          manually try the Job again.  This value SHOULD be supported.

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       o  'unsupported-compression': The Job was aborted by the system
          because the Printer determined, while attempting to decompress the
          Document data, that the compression algorithm is actually not
          among those supported by the Printer.  This value MUST be
          supported, since "compression" is a REQUIRED operation attribute.

       o  'compression-error': The Job was aborted by the system because the
          Printer encountered an error in the Document data while
          decompressing it.  If the Printer posts this reason, the Document
          data has already passed any tests that would have led to the
          'unsupported-compression' "job-state-reasons" value.

       o  'unsupported-document-format': The Job was aborted by the system
          because the Document data's "document-format" attribute is not
          among those supported by the Printer.  If the Client specifies
          "document-format" as 'application/octet-stream', the Printer MAY
          abort the Job and post this reason even though the
          "document-format" value is among the values of the Printer's
          "document-format-supported" Printer attribute but not among the
          auto-sensed Document formats.  This value MUST be supported, since
          "document-format" is a REQUIRED operation attribute.

       o  'document-format-error': The Job was aborted by the system because
          the Printer encountered an error in the Document data while
          processing it.  If the Printer posts this reason, the Document
          data has already passed any tests that would have led to the
          'unsupported-document-format' "job-state-reasons" value.

       o  'processing-to-stop-point': The requester has issued a Cancel-Job
          operation or the Printer has aborted the Job, but the Printer is
          still performing some actions on the Job until a specified stop
          point occurs or Job termination/cleanup is completed.

          If the implementation requires some measurable time to cancel the
          Job in the 'processing' or 'processing-stopped' Job state, the
          Printer MUST use this value to indicate that the Printer is still
          performing some actions on the Job while the Job remains in the
          'processing' or 'processing-stopped' state.  Once at the stop
          point, the Printer moves the Job from the 'processing' state to
          the 'canceled' or 'aborted' Job state.

       o  'service-off-line': The Printer is offline and accepting no Jobs.
          All 'pending' Jobs are put into the 'pending-held' state.  This
          situation could be true if the service's or Document transform's
          input is impaired or broken.

       o  'job-completed-successfully': The Job completed successfully.
          This value SHOULD be supported.

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       o  'job-completed-with-warnings': The Job completed with warnings.
          This value SHOULD be supported if the implementation detects
          warnings.

       o  'job-completed-with-errors': The Job completed with errors (and
          possibly warnings too).  This value SHOULD be supported if the
          implementation detects errors.

       o  'job-restartable': This Job is retained (see Section 5.3.7.2) and
          is currently able to be restarted using the Restart-Job (see
          Section 4.3.7) or Resubmit-Job [PWG5100.11] operation.  If
          'job-restartable' is a value of the Job's "job-state-reasons"
          attribute, then the Printer MUST accept a Restart-Job operation
          for that Job.  This value SHOULD be supported if the Restart-Job
          operation is supported.

       o  'queued-in-device': The Job has been forwarded to a device or
          print system that is unable to send back status.  The Printer sets
          the Job's "job-state" attribute to 'completed' and adds the
          'queued-in-device' value to the Job's "job-state-reasons"
          attribute to indicate that the Printer has no additional
          information about the Job and never will have any better
          information.  See Section 5.3.7.1.

    5.3.9.  job-state-message (text(MAX))

       This RECOMMENDED attribute specifies information about the
       "job-state" and "job-state-reasons" attributes in human-readable
       text.  If the Printer supports this attribute, the Printer MUST be
       able to generate this message in any of the natural languages
       identified by the Printer's "generated-natural-language-supported"
       attribute (see the "attributes-natural-language" operation attribute
       specified in Section 4.1.4.1).

       The value SHOULD NOT contain additional information not contained in
       the values of the "job-state" and "job-state-reasons" attributes,
       such as interpreter error information.  Otherwise, application
       programs might attempt to parse the (localized) text.  For such
       additional information, such as interpreter errors for application
       program consumption or specific Document access errors, new
       attributes with 'keyword' values need to be developed and registered.

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    5.3.10.  job-detailed-status-messages (1setOf text(MAX))

       This attribute specifies additional detailed and technical
       information about the Job.  The Printer SHOULD localize the message,
       unless such localization would obscure the technical meaning of the
       message.  Clients MUST NOT attempt to parse the value of this
       attribute.  See "job-document-access-errors" (Section 5.3.11) for
       additional errors that a program can process.

    5.3.11.  job-document-access-errors (1setOf text(MAX))

       This attribute provides additional information about each Document
       access error for this Job encountered by the Printer after it
       returned a response to the Print-URI or Send-URI operation and
       subsequently attempted to access document(s) supplied in the
       Print-URI or Send-URI operation.  For errors in the protocol that is
       identified by the URI scheme in the "document-uri" operation
       attribute, such as 'http:' or 'ftp:', the error code is returned in
       parentheses, followed by the URI.  For example:

       (404) http://www.example.com/filename.pdf

       Most Internet protocols use decimal error codes (unlike IPP), so the
       ASCII error code representation is in decimal.

    5.3.12.  number-of-documents (integer(0:MAX))

       This attribute indicates the number of Documents in the Job, i.e.,
       the number of Send-Document, Send-URI, Print-Job, or Print-URI
       operations that the Printer has accepted for this Job, regardless of
       whether the Document data has reached the Printer.

       Implementations supporting the RECOMMENDED Create-Job/Send-Document/
       Send-URI operations SHOULD support this attribute so that Clients can
       query the number of Documents in each Job.

    5.3.13.  output-device-assigned (name(127))

       This attribute identifies the Output Device to which the Printer has
       assigned this Job.  If an Output Device implements an embedded
       Printer, the Printer SHOULD set this attribute.  If a print server
       implements a Printer, the value MAY be empty (zero-length string) or
       not returned until the Printer assigns an Output Device to the Job.
       This attribute is particularly useful when a single Printer supports
       multiple devices (so-called "fan-out" -- see Section 3.1).

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    5.3.14.  Event Time Job Status Attributes

       This section defines the Job Status attributes that indicate the time
       at which certain events occur for a Job.  If the Job event has not
       yet occurred, then the Printer MUST return the 'no-value' out-of-band
       value (see the beginning of Section 5.1).  The
       "time-at-xxx (integer)" attributes represent time as an 'integer'
       representing the number of seconds since the device was powered up
       (informally called "time ticks").  The "date-time-at-xxx (dateTime)"
       attributes represent time as 'dateTime' representing date and time
       (including an offset from UTC).

       In order to populate these attributes, the Printer copies the
       value(s) of the following Printer Status attributes at the time the
       event occurs:

       1.  the value in the Printer's "printer-up-time" attribute for the
           "time-at-xxx (integer)" attributes.

       2.  the value in the Printer's "printer-current-time" attribute for
           the "date-time-at-xxx (dateTime)" attributes.

       If the Printer resets its "printer-up-time" attribute to 1 on
       power-up (see Section 5.4.29) and has persistent Jobs, then it MUST
       change all of those Jobs' "time-at-xxx (integer)" (time tick) Job
       attributes whose events have occurred either to:

       1.  0 to indicate that the event happened before the most recent
           power-up, or

       2.  the negative of the number of seconds before the most recent
           power-up that the event took place, if the Printer knows the
           exact number of seconds.

       If a Client queries a "time-at-xxx (integer)" time tick Job attribute
       and finds the value to be 0 or negative, the Client MUST assume that
       the event occurred in some life other than the Printer's current
       life.

       Note: A Printer does not change the values of any
       "date-time-at-xxx (dateTime)" Job attributes on power-up.

    5.3.14.1.  time-at-creation (integer(MIN:MAX))

       This REQUIRED attribute indicates the time at which the Job was
       created.

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    5.3.14.2.  time-at-processing (integer(MIN:MAX))

       This REQUIRED attribute indicates the time at which the Job first
       began processing after the Job Creation request or the most recent
       Restart-Job operation.  The out-of-band 'no-value' value is returned
       if the Job has not yet been in the 'processing' state (see the
       beginning of Section 5.1).

    5.3.14.3.  time-at-completed (integer(MIN:MAX))

       This REQUIRED attribute indicates the time at which the Job entered a
       Terminating State ('completed', 'canceled', or 'aborted').  The
       out-of-band 'no-value' value is returned if the Job has not yet
       completed, been canceled, or aborted (see the beginning of
       Section 5.1).

    5.3.14.4.  job-printer-up-time (integer(1:MAX))

       This REQUIRED Job Status attribute indicates the amount of time (in
       seconds) that the Printer implementation has been up and running.
       This attribute is an alias for the "printer-up-time" Printer Status
       attribute (see Section 5.4.29).

       A Client MAY request this attribute in a Get-Job-Attributes or
       Get-Jobs request and use the value returned in combination with other
       requested Event Time Job Status attributes in order to display time
       attributes to a user.  The difference between this attribute and the
       'integer' value of a "time-at-xxx" attribute is the number of seconds
       ago that the "time-at-xxx" event occurred.  A Client can compute the
       wall-clock time at which the "time-at-xxx" event occurred by
       subtracting this difference from the Client's wall-clock time.

    5.3.14.5.  date-time-at-creation (dateTime|unknown)

       This RECOMMENDED attribute indicates the date and time at which the
       Job was created.

    5.3.14.6.  date-time-at-processing (dateTime|unknown|no-value)

       This RECOMMENDED attribute indicates the date and time at which the
       Job first began processing after the Job Creation request or the most
       recent Restart-Job operation.

    5.3.14.7.  date-time-at-completed (dateTime|unknown|no-value)

       This RECOMMENDED attribute indicates the date and time at which the
       Job entered a Terminating State ('completed', 'canceled', or
       'aborted').

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    5.3.15.  number-of-intervening-jobs (integer(0:MAX))

       This attribute indicates the number of Jobs that are "ahead" of this
       Job in the relative chronological order of expected time to complete
       (i.e., the current scheduled order).  For efficiency, it is only
       necessary to calculate this value when an operation is performed that
       requests this attribute.

    5.3.16.  job-message-from-operator (text(127))

       This attribute provides a message from an Operator, Administrator, or
       "intelligent" process to indicate to the End User the reasons for
       modification or other management action taken on a Job.

    5.3.17.  Job Size Attributes

       This subsection defines Job attributes that describe the size of the
       Job.  These attributes are not intended to be counters; they are
       intended to be useful routing and scheduling information if known.
       For these attributes, the Printer can try to compute the value if it
       is not supplied in the Job Creation request.  Even if the Client does
       supply a value for these three attributes in the Job Creation
       request, the Printer MAY choose to change the value if the Printer is
       able to compute a value that is more accurate than the
       Client-supplied value.  The Printer can determine the correct value
       for these attributes either right at Job submission time or at any
       later point in time.

    5.3.17.1.  job-k-octets (integer(0:MAX))

       This attribute specifies the total size of the Document(s) in
       K octets, i.e., in units of 1024 octets requested to be processed
       in the Job.  The value MUST be rounded up, so that a Job between
       1 and 1024 octets MUST be indicated as being 1, 1025 to 2048 MUST
       be 2, etc.

       This value MUST NOT include the multiplicative factors contributed by
       the number of copies specified by the "copies" attribute, independent
       of whether the device can process multiple copies without making
       multiple passes over the Job or Document data and independent of
       whether the output is collated or not.  Thus, the value is
       independent of the implementation and indicates the size of the
       Document(s) measured in K octets independent of the number of copies.

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       This value also MUST NOT include the multiplicative factor due to a
       copies instruction embedded in the Document data.  If the Document
       data actually includes replications of the Document data, this value
       will include such replication.  In other words, this value is always
       the size of the source Document data, rather than a measure of the
       hardcopy output to be produced.

    5.3.17.2.  job-impressions (integer(0:MAX))

       This RECOMMENDED attribute specifies the total size in number of
       Impressions of the Document(s) being submitted (see the definition of
       "Impression" in Section 2.3.4).

       As with "job-k-octets", this value MUST NOT include the
       multiplicative factors contributed by the number of copies specified
       by the "copies" attribute, independent of whether the device can
       process multiple copies without making multiple passes over the Job
       or Document data and independent of whether the output is collated or
       not.  Thus, the value is independent of the implementation and
       reflects the size of the Document(s) measured in Impressions
       independent of the number of copies.

       As with "job-k-octets", this value also MUST NOT include the
       multiplicative factor due to a copies instruction embedded in the
       Document data.  If the Document data actually includes replications
       of the Document data, this value will include such replication.  In
       other words, this value is always the number of Impressions in the
       source Document data, rather than a measure of the number of
       Impressions to be produced by the Job.

    5.3.17.3.  job-media-sheets (integer(1:MAX))

       This RECOMMENDED attribute specifies the total number of Media Sheets
       to be produced for this Job.

       Unlike the "job-k-octets" and the "job-impressions" attributes, this
       value MUST include the multiplicative factors contributed by the
       number of copies specified by the "copies" attribute and a 'number of
       copies' instruction embedded in the Document data, if any.  This
       difference allows the Administrator to control the lower and upper
       bounds of both (1) the size of the Document(s) with
       "job-k-octets-supported" and "job-impressions-supported" and
       (2) the size of the Job with "job-media-sheets-supported".

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    5.3.18.  Job Progress Attributes

       This subsection defines Job attributes that describe the progress of
       the Job.  These attributes are intended to be counters.  That is, the
       values for a Job that has not started processing MUST be 0.  When the
       Job's "job-state" is 'processing' or 'processing-stopped', this value
       is intended to contain the amount of the Job that has been processed
       to the time at which the attributes are requested.  When the Job
       enters the 'completed', 'canceled', or 'aborted' states, these values
       are the final values for the Job.

    5.3.18.1.  job-k-octets-processed (integer(0:MAX))

       This attribute specifies the total number of octets processed in
       K octets, i.e., in units of 1024 octets so far.  The value MUST be
       rounded up, so that a Job between 1 and 1024 octets inclusive MUST be
       indicated as being 1, 1025 to 2048 inclusive MUST be 2, etc.

       For implementations where multiple copies are produced by the
       interpreter with only a single pass over the data, the final value
       MUST be equal to the value of the "job-k-octets" attribute.  For
       implementations where multiple copies are produced by the interpreter
       by processing the data for each copy, the final value MUST be a
       multiple of the value of the "job-k-octets" attribute.

    5.3.18.2.  job-impressions-completed (integer(0:MAX))

       This RECOMMENDED attribute specifies the number of Impressions
       completed for the Job so far.  For printing devices, the Impressions
       completed includes interpreting, marking, and stacking the output.

    5.3.18.3.  job-media-sheets-completed (integer(0:MAX))

       This RECOMMENDED Job attribute specifies the number of Media Sheets
       that have been marked and stacked for the entire Job so far, whether
       those sheets have been processed on one side or on both.

    5.3.19.  attributes-charset (charset)

       This REQUIRED attribute is populated using the value in the
       Client-supplied "attributes-charset" attribute in the Job Creation
       request.  It identifies the charset (coded character set and encoding
       method) used by any Job attributes with attribute syntaxes 'text' and
       'name' that were supplied by the Client in the Job Creation request.
       See Section 4.1.4 for a complete description of the
       "attributes-charset" operation attribute.

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       This attribute does not indicate the charset in which the 'text' and
       'name' values are stored internally in the Job.  The internal charset
       is implementation defined.  The Printer MUST convert from whatever
       the internal charset is to that being requested in an operation as
       specified in Section 4.1.4.

    5.3.20.  attributes-natural-language (naturalLanguage)

       This REQUIRED attribute is populated using the value in the
       Client-supplied "attributes-natural-language" attribute in the Job
       Creation request.  It identifies the natural language used for any
       Job attributes with attribute syntaxes 'text' and 'name' that were
       supplied by the Client in the Job Creation request.  See
       Section 4.1.4 for a complete description of the
       "attributes-natural-language" operation attribute.  See
       Sections 5.1.2.2 and 5.1.3.2 for how a Natural Language Override can
       be supplied explicitly for each 'text' and 'name' attribute value
       that differs from the value identified by the
       "attributes-natural-language" attribute.

    5.4.  Printer Description and Status Attributes

       These attributes form the attribute group called
       "printer-description".  Tables 16 and 17 summarize these attributes,
       their syntax, and whether they are REQUIRED for a Printer to support.
       If they are not indicated as REQUIRED, they are OPTIONAL.  The
       maximum size in octets for 'text' and 'name' attributes is indicated
       in parentheses.

       Note: How these attributes are set by an Administrator is outside the
       scope of this document.

       +-----------------------------+-----------------------+-------------+
       | Attribute                   | Syntax                | REQUIRED?   |
       +-----------------------------+-----------------------+-------------+
       | charset-configured          | charset               | REQUIRED    |
       +-----------------------------+-----------------------+-------------+
       | charset-supported           | 1setOf charset        | REQUIRED    |
       +-----------------------------+-----------------------+-------------+
       | color-supported             | boolean               | RECOMMENDED |
       +-----------------------------+-----------------------+-------------+
       | compression-supported       | 1setOf type2 keyword  | REQUIRED    |
       +-----------------------------+-----------------------+-------------+
       | document-format-default     | mimeMediaType         | REQUIRED    |
       +-----------------------------+-----------------------+-------------+
       | document-format-supported   | 1setOf mimeMediaType  | REQUIRED    |

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       +-----------------------------+-----------------------+-------------+
       | generated-natural-language- | 1setOf                | REQUIRED    |
       | supported                   | naturalLanguage       |             |
       +-----------------------------+-----------------------+-------------+
       | ipp-versions-supported      | 1setOf type2 keyword  | REQUIRED    |
       +-----------------------------+-----------------------+-------------+
       | job-impressions-supported   | rangeOfInteger(0:MAX) | RECOMMENDED |
       +-----------------------------+-----------------------+-------------+
       | job-k-octets-supported      | rangeOfInteger(0:MAX) |             |
       +-----------------------------+-----------------------+-------------+
       | job-media-sheets-supported  | rangeOfInteger(1:MAX) |             |
       +-----------------------------+-----------------------+-------------+
       | multiple-document-jobs-     | boolean               | RECOMMENDED |
       | supported                   |                       |             |
       +-----------------------------+-----------------------+-------------+
       | multiple-operation-time-out | integer(1:MAX)        | RECOMMENDED |
       +-----------------------------+-----------------------+-------------+
       | natural-language-configured | naturalLanguage       | REQUIRED    |
       +-----------------------------+-----------------------+-------------+
       | operations-supported        | 1setOf type2 enum     | REQUIRED    |
       +-----------------------------+-----------------------+-------------+
       | pdl-override-supported      | type2 keyword         | REQUIRED    |
       +-----------------------------+-----------------------+-------------+
       | printer-driver-installer    | uri                   |             |
       +-----------------------------+-----------------------+-------------+
       | printer-info                | text(127)             | RECOMMENDED |
       +-----------------------------+-----------------------+-------------+
       | printer-location            | text(127)             | RECOMMENDED |
       +-----------------------------+-----------------------+-------------+
       | printer-make-and-model      | text(127)             | RECOMMENDED |
       +-----------------------------+-----------------------+-------------+
       | printer-message-from-       | text(127)             |             |
       | operator                    |                       |             |
       +-----------------------------+-----------------------+-------------+
       | printer-more-info-          | uri                   |             |
       | manufacturer                |                       |             |
       +-----------------------------+-----------------------+-------------+
       | printer-name                | name(127)             | REQUIRED    |
       +-----------------------------+-----------------------+-------------+
       | reference-uri-schemes-      | 1setOf uriScheme      |             |
       | supported                   |                       |             |
       +-----------------------------+-----------------------+-------------+

               Table 16: Printer Description Attributes (READ-WRITE)

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       +------------------------------+----------------------+-------------+
       | Attribute                    | Syntax               | REQUIRED?   |
       +------------------------------+----------------------+-------------+
       | pages-per-minute-color       | integer(0:MAX)       | RECOMMENDED |
       +------------------------------+----------------------+-------------+
       | pages-per-minute             | integer(0:MAX)       | RECOMMENDED |
       +------------------------------+----------------------+-------------+
       | printer-current-time         | dateTime|unknown     | RECOMMENDED |
       +------------------------------+----------------------+-------------+
       | printer-is-accepting-jobs    | boolean              | REQUIRED    |
       +------------------------------+----------------------+-------------+
       | printer-more-info            | uri                  | RECOMMENDED |
       +------------------------------+----------------------+-------------+
       | printer-state                | type1 enum           | REQUIRED    |
       +------------------------------+----------------------+-------------+
       | printer-state-message        | text(MAX)            | RECOMMENDED |
       +------------------------------+----------------------+-------------+
       | printer-state-reasons        | 1setOf type2 keyword | REQUIRED    |
       +------------------------------+----------------------+-------------+
       | printer-up-time              | integer(1:MAX)       | REQUIRED    |
       +------------------------------+----------------------+-------------+
       | printer-uri-supported        | 1setOf uri           | REQUIRED    |
       +------------------------------+----------------------+-------------+
       | queued-job-count             | integer(0:MAX)       | REQUIRED    |
       +------------------------------+----------------------+-------------+
       | uri-authentication-supported | 1setOf type2 keyword | REQUIRED    |
       +------------------------------+----------------------+-------------+
       | uri-security-supported       | 1setOf type2 keyword | REQUIRED    |
       +------------------------------+----------------------+-------------+

                  Table 17: Printer Status Attributes (READ-ONLY)

    5.4.1.  printer-uri-supported (1setOf uri)

       This REQUIRED Printer attribute contains one or more URIs for the
       Printer.  It MAY contain more than one URI for the Printer.  An
       Administrator determines a Printer's URIs and configures this
       attribute to contain those URIs by some means outside the scope of
       this IPP/1.1 document.  The precise format of the URIs is
       implementation dependent and depends on the protocol.  See
       Sections 5.4.2 and 5.4.3 for a description of the
       "uri-authentication-supported" and "uri-security-supported"
       attributes, both of which are the REQUIRED companion attributes to
       this "printer-uri-supported" attribute.  See Sections 3.4 ("Object
       Identity") and 9.2 ("URIs in Operation, Job, and Printer Attributes")
       for more information.

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    5.4.2.  uri-authentication-supported (1setOf type2 keyword)

       This REQUIRED Printer attribute MUST have the same cardinality
       (contain the same number of values) as the "printer-uri-supported"
       attribute.  This attribute identifies the Client Authentication
       mechanism associated with each URI listed in the
       "printer-uri-supported" attribute.  The Printer uses the specified
       mechanism to identify the authenticated user (see Section 9.3).  The
       "i-th" value in "uri-authentication-supported" corresponds to the
       "i-th" value in "printer-uri-supported", and it describes the
       authentication mechanisms used by the Printer when accessed via that
       URI.  See [RFC8010] for more details on Client Authentication.

       The following standard 'keyword' values are defined:

       o  'none': There is no authentication mechanism associated with the
          URI.  The Printer assumes that the authenticated user is
          'anonymous'.

       o  'requesting-user-name': When a Client performs an operation whose
          target is the associated URI, the Printer assumes that the
          authenticated user is specified by the "requesting-user-name"
          operation attribute (see Section 9.3).  If the
          "requesting-user-name" attribute is absent in a request, the
          Printer assumes that the authenticated user is 'anonymous'.

       o  'basic': When a Client performs an operation whose target is the
          associated URI, the Printer challenges the Client with HTTP Basic
          authentication [RFC7617].  The Printer assumes that the
          authenticated user is the name received via the Basic
          authentication mechanism.

       o  'digest': When a Client performs an operation whose target is the
          associated URI, the Printer challenges the Client with HTTP Digest
          authentication [RFC7616].  The Printer assumes that the
          authenticated user is the name received via the Digest
          authentication mechanism.

       o  'certificate': When a Client performs an operation whose target is
          the associated URI, the Printer expects the Client to provide an
          X.509 certificate.  The Printer assumes that the authenticated
          user is one of the textual names (Common Name or Subject Alternate
          Names) contained within the certificate.

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    5.4.3.  uri-security-supported (1setOf type2 keyword)

       This REQUIRED Printer attribute MUST have the same cardinality
       (contain the same number of values) as the "printer-uri-supported"
       attribute.  This attribute identifies the security mechanisms used
       for each URI listed in the "printer-uri-supported" attribute.  The
       "i-th" value in "uri-security-supported" corresponds to the "i-th"
       value in "printer-uri-supported", and it describes the security
       mechanisms used for accessing the Printer via that URI.  See
       [RFC8010] for more details on security mechanisms.

       The following standard 'keyword' values are defined:

       o  'none': There are no secure communication channel protocols in use
          for the given URI.

       o  'tls': TLS [RFC5246] [RFC7525] is the secure communications
          channel protocol in use for the given URI.

       This attribute is orthogonal to the definition of a Client
       Authentication mechanism.  Specifically, 'none' does not exclude
       Client Authentication.  See Section 5.4.2.

       Consider the following example.  For a single Printer, an
       Administrator configures the "printer-uri-supported",
       "uri-authentication-supported", and "uri-security-supported"
       attributes as follows:

          "printer-uri-supported": 'ipp://printer.example.com/ipp/print/
          open-use-printer', 'ipp://printer.example.com/ipp/print/
          restricted-use-printer', 'ipps://printer.example.com/ipp/print/
          private-printer'

          "uri-authentication-supported": 'none', 'digest', 'basic'

          "uri-security-supported": 'none', 'none', 'tls'

       In this case, one Printer has three URIs.

       o  For the first URI, 'ipp://printer.example.com/ipp/print/
          open-use-printer', the value 'none' in "uri-security-supported"
          indicates that there is no secure channel protocol configured to
          run under HTTP.  The value of 'none' in
          "uri-authentication-supported" indicates that all users are
          'anonymous'.  There will be no challenge, and the Printer will
          ignore "requesting-user-name".

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       o  For the second URI, 'ipp://printer.example.com/ipp/print/
          restricted-use-printer', the value 'none' in
          "uri-security-supported" indicates that there is no secure channel
          protocol configured to run under HTTP.  The value of 'digest' in
          "uri-authentication-supported" indicates that the Printer will
          issue a challenge and that the Printer will use the name supplied
          by the Digest mechanism to determine the authenticated user (see
          Section 9.3).

       o  For the third URI, 'ipps://printer.example.com/ipp/print/
          private-printer', the value 'tls' in "uri-security-supported"
          indicates that TLS is being used to secure the channel.  The
          Client SHOULD be prepared to use TLS framing to negotiate an
          acceptable ciphersuite to use while communicating with the
          Printer.  In this case, the name implies the use of a secure
          communications channel, but the fact is made explicit by the
          presence of the 'tls' value in "uri-security-supported".  The
          Client does not need to resort to understanding which security
          mechanisms it must use by following naming conventions or by
          parsing the URI to determine which security mechanisms are
          implied.  The value of 'basic' in "uri-authentication-supported"
          indicates that the Printer will issue a challenge and that the
          Printer will use the name supplied by the Basic mechanism to
          determine the authenticated user (see Section 9.3).  Because this
          challenge occurs in a TLS session, the channel is secure.

       Some Printers will be configured to support only one channel (either
       configured to use TLS access or not) and only one authentication
       mechanism.  Such Printers only have one URI listed in the
       "printer-uri-supported" attribute.  No matter the configuration of
       the Printer (whether it has only one URI or more than one URI), a
       Client MUST supply only one URI in the target "printer-uri" operation
       attribute.

    5.4.4.  printer-name (name(127))

       This REQUIRED Printer attribute contains the name of the Printer.  It
       is a name that is more End User friendly than a URI.  An
       Administrator determines a Printer's name and sets this attribute to
       that name.  This name can be the last part of the Printer's URI, or
       it can be unrelated.  In non-US-English locales, a name can contain
       characters that are not allowed in a URI.

    5.4.5.  printer-location (text(127))

       This RECOMMENDED Printer attribute identifies the location of the
       device.  This could include things like 'in Room 123A, second floor
       of building XYZ'.

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    5.4.6.  printer-info (text(127))

       This RECOMMENDED Printer attribute provides descriptive information
       about this Printer.  This could include things like 'This printer can
       be used for printing color transparencies for HR presentations', or
       'Out of courtesy for others, please print only small (1-5 page) jobs
       at this printer', or even 'This printer is going away on July 1;
       please find a new printer'.

    5.4.7.  printer-more-info (uri)

       This RECOMMENDED Printer attribute contains a URI used to obtain more
       information about this specific Printer.  For example, this could be
       an HTTP URI referencing an HTML page accessible to a web browser.
       The information obtained from this URI is intended for End User
       consumption.  Features outside the scope of IPP can be accessed from
       this URI.  The information is intended to be specific to this Printer
       instance and site-specific services, e.g., Job pricing, services
       offered, and End User assistance.  The device manufacturer can
       initially populate this attribute.

    5.4.8.  printer-driver-installer (uri)

       This Printer attribute contains a URI to use to locate the driver
       installer for this Printer.  This attribute is intended for
       consumption by automata.  The mechanics of Printer driver
       installation are outside the scope of this document.  The device
       manufacturer can initially populate this attribute.

    5.4.9.  printer-make-and-model (text(127))

       This RECOMMENDED Printer attribute identifies the make and model of
       the device.  The device manufacturer can initially populate this
       attribute.

    5.4.10.  printer-more-info-manufacturer (uri)

       This Printer attribute contains a URI used to obtain more information
       about this type of device.  The information obtained from this URI is
       intended for End User consumption.  Features outside the scope of IPP
       can be accessed from this URI (e.g., latest firmware, upgrades,
       Printer drivers, optional features available, details on color
       support).  The information is intended to be germane to this Printer
       without regard to site-specific modifications or services.  The
       device manufacturer can initially populate this attribute.

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    5.4.11.  printer-state (type1 enum)

       This REQUIRED Printer attribute identifies the current state of the
       device.  The "printer-state reasons" attribute augments the
       "printer-state" attribute to give more detailed information about the
       Printer in the given Printer state.

       A Printer updates this attribute continually if asynchronous event
       notification [RFC3995] is supported.

       Standard enum values are defined in Table 18.  Values of
       "printer-state-reasons", such as 'spool-area-full' and
       'stopped-partly', MAY be used to provide further information.

       +-------+-----------------------------------------------------------+
       | Value | Symbolic Name and Description                             |
       +-------+-----------------------------------------------------------+
       | '3'   | 'idle': Indicates that new Jobs can start processing      |
       |       | without waiting.                                          |
       +-------+-----------------------------------------------------------+
       | '4'   | 'processing': Indicates that Jobs are processing; new     |
       |       | Jobs will wait before processing.                         |
       +-------+-----------------------------------------------------------+
       | '5'   | 'stopped': Indicates that no Jobs can be processed and    |
       |       | intervention is required.                                 |
       +-------+-----------------------------------------------------------+

                       Table 18: "printer-state" Enum Values

    5.4.12.  printer-state-reasons (1setOf type2 keyword)

       This REQUIRED Printer attribute supplies additional detail about the
       device's state.  Some of the value definitions indicate conformance
       requirements; the rest are OPTIONAL.

       Each 'keyword' value MAY have a suffix to indicate its level of
       severity.  The three levels are 'report' (least severe), 'warning',
       and 'error' (most severe):

       o  '-report': This suffix indicates that the reason is a "report".
          An implementation can choose to omit some or all reports.  Some
          reports specify finer granularity about the Printer state; others
          serve as a precursor to a warning.  A report MUST contain nothing
          that could affect the printed output.  Reports correspond to the
          'other' value for the prtAlertSeverityLevel property in the
          Printer MIB [RFC3805].

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       o  '-warning': This suffix indicates that the reason is a "warning".
          An implementation can choose to omit some or all warnings.
          Warnings serve as a precursor to an error.  A warning MUST contain
          nothing that prevents a Job from completing, though in some cases
          the output can be of lower quality.  Warnings correspond to the
          'warning' value for the prtAlertSeverityLevel property in the
          Printer MIB [RFC3805].

       o  '-error': This suffix indicates that the reason is an "error".  An
          implementation MUST include all errors.  If this attribute
          contains one or more errors, the Printer MUST be in the 'stopped'
          state.  Errors correspond to the 'critical' value for the
          prtAlertSeverityLevel property in the Printer MIB [RFC3805].

       If the implementation does not add any one of the three suffixes and
       the value is not 'none', Clients can assume that the reason is an
       "error" if the Printer is in the 'stopped' state and a "warning" if
       the Printer is in any other state.

       If a Printer controls more than one Output Device, each value of this
       attribute MAY apply to one or more of the Output Devices.  An error
       on one Output Device that does not stop the Printer as a whole MAY
       appear as a warning in the Printer's "printer-state-reasons"
       attribute.  If "printer-state" for such a Printer has a value of
       'stopped', then there MUST be an error reason among the values in the
       "printer-state-reasons" attribute.

       The following standard 'keyword' values are defined:

       o  'none': There are no reasons.  This state reason is semantically
          equivalent to "printer-state-reasons" without any value and MUST
          be used, since the '1setOf' attribute syntax requires at least one
          value.

       o  'other': The device has detected a condition other than one listed
          in this document.

       o  'connecting-to-device': The Printer has scheduled a Job on the
          Output Device and is in the process of connecting to a shared
          network Output Device (and might not be able to actually start
          printing the Job for an arbitrarily long time, depending on the
          usage of the Output Device by other servers on the network).

       o  'cover-open': One or more covers on the device are open,
          equivalent to a prtCoverStatus [RFC3805] of 3 (coverOpen).

       o  'developer-empty: The device is out of developer.

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       o  'developer-low': The device is low on developer.

       o  'door-open': One or more doors on the device are open, equivalent
          to a prtCoverStatus [RFC3805] of 3 (coverOpen).

       o  'fuser-over-temp': The fuser temperature is above normal,
          equivalent to a prtMarkerStatus [RFC3805] of 19 (the sum of
          "Unavailable because Broken" (3) and "Critical Alerts" (16)).

       o  'fuser-under-temp': The fuser temperature is below normal,
          equivalent to a prtMarkerStatus [RFC3805] of 19 (the sum of
          "Unavailable because Broken" (3) and "Critical Alerts" (16)).

       o  'input-tray-missing': One or more input trays are not in the
          device, equivalent to a prtInputStatus [RFC3805] of 19 (the sum of
          "Unavailable because Broken" (3) and "Critical Alerts" (16)).

       o  'interlock-open': One or more interlock devices on the Printer are
          unlocked, equivalent to a prtCoverStatus [RFC3805] of 5
          (interlockOpen).

       o  'interpreter-resource-unavailable': An interpreter resource is
          unavailable (i.e., font, form).

       o  'marker-supply-empty: The device is out of at least one marker
          supply, e.g., toner, ink, ribbon.

       o  'marker-supply-low': The device is low on at least one marker
          supply, e.g., toner, ink, ribbon.

       o  'marker-waste-almost-full': The device marker supply waste
          receptacle is almost full.

       o  'marker-waste-full': The device marker supply waste receptacle is
          full.

       o  'media-empty': At least one input tray is empty, equivalent to a
          prtInputStatus [RFC3805] of 19 (the sum of "Unavailable because
          Broken" (3) and "Critical Alerts" (16)).

       o  'media-jam': The device has a media jam, equivalent to a
          prtInputStatus [RFC3805] of 19 (the sum of "Unavailable because
          Broken" (3) and "Critical Alerts" (16)).

       o  'media-low': At least one input tray is low on media, equivalent
          to a prtInputStatus [RFC3805] of 8 (Non-Critical Alerts).

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       o  'media-needed': A tray has run out of media, equivalent to a
          prtInputStatus [RFC3805] value of 17 (the sum of "Unavailable and
          OnRequest" (1) and "Critical Alerts" (16)).

       o  'moving-to-paused': Someone has paused the Printer using the
          Pause-Printer operation (see Section 4.2.7) or other means, but
          the device(s) is taking an appreciable time to stop.  Later, when
          all output has stopped, "printer-state" becomes 'stopped', and the
          'paused' value replaces the 'moving-to-paused' value in the
          "printer-state-reasons" attribute.  This value MUST be supported
          if the Pause-Printer operation is supported and the implementation
          takes significant time to pause a device in certain circumstances.

       o  'opc-life-over': The optical photo conductor is no longer
          functioning, equivalent to a prtMarkerStatus [RFC3805] of 19
          (the sum of "Unavailable because Broken" (3) and
          "Critical Alerts" (16)).

       o  'opc-near-eol': The optical photo conductor is near its end of
          life, equivalent to a prtMarkerStatus [RFC3805] of 8 (Non-Critical
          Alerts).

       o  'output-area-almost-full': One or more output areas are almost
          full, e.g., tray, stacker, collator, equivalent to a
          prtOutputStatus [RFC3805] of 8 (Non-Critical Alerts).

       o  'output-area-full': One or more output areas are full, e.g., tray,
          stacker, collator, equivalent to a prtInputStatus [RFC3805] of 19
          (the sum of "Unavailable because Broken" (3) and
          "Critical Alerts" (16)).

       o  'output-tray-missing': One or more output trays are not in the
          device, equivalent to a prtOutputStatus [RFC3805] of 19 (the sum
          of "Unavailable because Broken" (3) and "Critical Alerts" (16)).

       o  'paused': Someone has paused the Printer using the Pause-Printer
          operation (see Section 4.2.7) or other means, and the Printer's
          "printer-state" is 'stopped'.  In this state, a Printer MUST NOT
          produce printed output, but it MUST perform other operations
          requested by a Client.  If a Printer had been printing a Job when
          the Printer was paused, the Printer MUST resume printing that Job
          when the Printer is no longer paused and leave no evidence in the
          printed output of such a pause.  This value MUST be supported if
          the Pause-Printer operation is supported.

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       o  'shutdown': Someone has removed a Printer from service, and the
          device can be powered down or physically removed.  In this state,
          a Printer MUST NOT produce printed output, and unless the Printer
          is realized by a print server that is still active, the Printer
          MUST perform no other operations requested by a Client, including
          returning this value.  If a Printer had been printing a Job when
          it was shut down, the Printer MAY resume printing that Job when
          the Printer is restarted.  If the Printer resumes printing such a
          Job, it can leave evidence in the printed output of such a
          shutdown, e.g., the part printed before the shutdown can be
          printed a second time after the shutdown.

       o  'spool-area-full': The limit of persistent storage allocated for
          spooling has been reached.  The Printer is temporarily unable to
          accept more Jobs.  The Printer will remove this value when it is
          able to accept more Jobs.  This value SHOULD be used by a
          non-spooling Printer that only accepts one or a small number of
          Jobs at a time or by a spooling Printer that has filled the spool
          space.

       o  'stopped-partly': When a Printer controls more than one Output
          Device, this reason indicates that one or more Output Devices are
          stopped.  If the reason is a report, fewer than half of the Output
          Devices are stopped.  If the reason is a warning, fewer than all
          of the Output Devices are stopped.

       o  'stopping': The Printer is in the process of stopping the device
          and will be stopped in a while.  When the device is stopped, the
          Printer will change the Printer's state to 'stopped'.  The
          'stopping-warning' reason is never an error, even for a Printer
          with a single Output Device.  When an Output Device ceases
          accepting Jobs, the Printer will have this reason while the Output
          Device completes printing.

       o  'timed-out': The server was able to connect to the Output Device
          (or is always connected) but was unable to get a response from the
          Output Device.

       o  'toner-empty': The device is out of toner.

       o  'toner-low': The device is low on toner.

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    5.4.13.  printer-state-message (text(MAX))

       This RECOMMENDED Printer attribute specifies information about the
       "printer-state" and "printer-state-reasons" attributes in human-
       readable text.  If the Printer supports this attribute, the Printer
       MUST be able to generate this message in any of the natural languages
       identified by the Printer's "generated-natural-language-supported"
       attribute (see the "attributes-natural-language" operation attribute
       specified in Section 4.1.4.1).

    5.4.14.  ipp-versions-supported (1setOf type2 keyword)

       This REQUIRED attribute identifies the IPP version(s) that this
       Printer supports, including major and minor versions, i.e., the
       version numbers for which this Printer implementation meets the
       conformance requirements.  For version number validation, the Printer
       matches the (2-octet binary) "version-number" parameter supplied by
       the Client in each request (see Sections 4.1.1 and 4.1.8) with the
       (US-ASCII) 'keyword' values of this attribute.

       The following standard 'keyword' values are defined in this document:

       o  '1.0': Meets the conformance requirements of IPP version 1.0 as
          specified in RFC 2566 [RFC2566] and RFC 2565 [RFC2565], including
          any extensions registered according to Section 7 and any extension
          defined in this version or any future version of the IPP Model and
          Semantics document (this document) or the IPP Encoding and
          Transport document [RFC8010] following the rules, if any, when the
          "version-number" parameter is '1.0'.

       o  '1.1': Meets the conformance requirements of IPP version 1.1 as
          specified in this document and [RFC8010], including any extensions
          registered according to Section 7 and any extension defined in any
          future versions of this document or [RFC8010] following the rules,
          if any, when the "version-number" parameter is '1.1'.

       Additional values are defined in "IPP Version 2.0, 2.1, and 2.2"
       [PWG5100.12].

    5.4.15.  operations-supported (1setOf type2 enum)

       This REQUIRED Printer attribute specifies the set of supported
       operations for this Printer and contained Jobs.

       This attribute is encoded as any other enum attribute syntax
       according to [RFC8010] as 32 bits.  However, all 32-bit enum values
       for this attribute MUST NOT exceed 0x00007fff, since these same
       values are also passed in two octets in the "operation-id" field (see

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       Section 4.1.1) in each Protocol request with the two high-order
       octets omitted in order to indicate the operation being performed
       [RFC8010].

       Table 19 lists the "operations-supported" attribute and
       "operation-id" parameter (see Section 4.1.2) enum values that are
       defined in this document.

       +---------------+---------------------------------------------------+
       | Value         | Operation Name                                    |
       +---------------+---------------------------------------------------+
       | 0x0000        | reserved, not used                                |
       +---------------+---------------------------------------------------+
       | 0x0001        | reserved, not used                                |
       +---------------+---------------------------------------------------+
       | 0x0002        | Print-Job                                         |
       +---------------+---------------------------------------------------+
       | 0x0003        | Print-URI                                         |
       +---------------+---------------------------------------------------+
       | 0x0004        | Validate-Job                                      |
       +---------------+---------------------------------------------------+
       | 0x0005        | Create-Job                                        |
       +---------------+---------------------------------------------------+
       | 0x0006        | Send-Document                                     |
       +---------------+---------------------------------------------------+
       | 0x0007        | Send-URI                                          |
       +---------------+---------------------------------------------------+
       | 0x0008        | Cancel-Job                                        |
       +---------------+---------------------------------------------------+
       | 0x0009        | Get-Job-Attributes                                |
       +---------------+---------------------------------------------------+
       | 0x000a        | Get-Jobs                                          |
       +---------------+---------------------------------------------------+
       | 0x000b        | Get-Printer-Attributes                            |
       +---------------+---------------------------------------------------+
       | 0x000c        | Hold-Job                                          |
       +---------------+---------------------------------------------------+
       | 0x000d        | Release-Job                                       |
       +---------------+---------------------------------------------------+
       | 0x000e        | Restart-Job                                       |
       +---------------+---------------------------------------------------+
       | 0x000f        | reserved for a future operation                   |

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       +---------------+---------------------------------------------------+
       | 0x0010        | Pause-Printer                                     |
       +---------------+---------------------------------------------------+
       | 0x0011        | Resume-Printer                                    |
       +---------------+---------------------------------------------------+
       | 0x0012        | Purge-Jobs                                        |
       +---------------+---------------------------------------------------+
       | 0x0013-0x3fff | additional registered operations (see the IANA    |
       |               | IPP registry and Section 7.8)                     |
       +---------------+---------------------------------------------------+
       | 0x4000-0x7fff | reserved for vendor extensions (see Section 7.8)  |
       +---------------+---------------------------------------------------+

                   Table 19: "operations-supported" Enum Values

    5.4.16.  multiple-document-jobs-supported (boolean)

       This RECOMMENDED Printer attribute indicates whether the Printer
       supports more than one Document per Job, i.e., more than one
       Send-Document operation with Document data and/or Send-URI
       operations.  If the Printer supports the Create-Job and Send-Document
       operations (see Sections 4.2.4 and 4.3.1), it MUST support this
       attribute.

    5.4.17.  charset-configured (charset)

       This REQUIRED Printer attribute identifies the charset that the
       Printer has been configured to represent 'text' and 'name' Printer
       attributes that are set by the Operator, Administrator, or
       manufacturer, i.e., for "printer-name" (name), "printer-location"
       (text), "printer-info" (text), and "printer-make-and-model" (text).
       Therefore, the value of the Printer's "charset-configured" attribute
       MUST also be among the values of the Printer's "charset-supported"
       attribute.

    5.4.18.  charset-supported (1setOf charset)

       This REQUIRED Printer attribute identifies the set of charsets that
       the Printer and contained Jobs support in attributes with attribute
       syntaxes 'text' and 'name'.  At least the value 'utf-8' MUST be
       present, since IPP objects MUST support the UTF-8 [RFC3629] charset.
       If a Printer supports a charset, it means that for all attributes of
       syntaxes 'text' and 'name' the Printer MUST (1) accept the charset in
       requests and (2) return the charset in responses as needed.

       If more charsets than UTF-8 are supported, the Printer MUST perform
       charset conversion between the charsets as described in
       Section 4.1.4.2.

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    5.4.19.  natural-language-configured (naturalLanguage)

       This REQUIRED Printer attribute identifies the natural language that
       the Printer has been configured to represent 'text' and 'name'
       Printer attributes that are set by the Operator, Administrator, or
       manufacturer, i.e., for "printer-name" (name), "printer-location"
       (text), "printer-info" (text), and "printer-make-and-model" (text).
       When returning these Printer attributes, the Printer MAY return them
       in the configured natural language specified by this attribute,
       instead of the natural language requested by the Client in the
       "attributes-natural-language" operation attribute.  See
       Section 4.1.4.1 for the specification of the OPTIONAL support for
       multiple natural languages.  Therefore, the value of the Printer's
       "natural-language-configured" attribute MUST also be among the values
       of the Printer's "generated-natural-language-supported" attribute.

    5.4.20.  generated-natural-language-supported (1setOf naturalLanguage)

       This REQUIRED Printer attribute identifies the natural language(s)
       that the Printer and contained Jobs support in attributes with
       attribute syntaxes 'text' and 'name'.  The natural language(s)
       supported depends on implementation and/or configuration.  Unlike
       charsets, Printers MUST accept requests with any natural language or
       any Natural Language Override whether the natural language is
       supported or not.

       If a Printer supports a natural language, it means that for any of
       the attributes for which the Printer or Job generates messages, i.e.,
       for the "job-state-message" and "printer-state-message" attributes
       and operation messages (see Section 4.1.5) in operation responses,
       the Printer and Job MUST be able to generate messages in any of the
       Printer's supported natural languages.  See Sections 4.1.4, 5.1.2,
       and 5.1.3 for the definitions of 'text' and 'name' attributes in
       operation requests and responses.

       Note: A Printer that supports multiple natural languages often has
       separate catalogs of messages, one for each natural language
       supported.

    5.4.21.  document-format-default (mimeMediaType)

       This REQUIRED Printer attribute identifies the Document format that
       the Printer has been configured to assume if the Client does not
       supply a "document-format" operation attribute in any of the
       operation requests that supply Document data.  The standard values
       for this attribute are Internet media types (sometimes called "MIME
       media types").  For further details, see the description of the
       'mimeMediaType' attribute syntax in Section 5.1.10.

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    5.4.22.  document-format-supported (1setOf mimeMediaType)

       This REQUIRED Printer attribute identifies the set of Document
       formats that the Printer and contained Jobs can support.  For further
       details, see the description of the 'mimeMediaType' attribute syntax
       in Section 5.1.10.

    5.4.23.  printer-is-accepting-jobs (boolean)

       This REQUIRED Printer attribute indicates whether the Printer is
       currently able to accept Jobs, i.e., is accepting Print-Job,
       Print-URI, and Create-Job requests.  If the value is 'true', the
       Printer is accepting Jobs.  If the value is 'false', the Printer is
       currently rejecting any Jobs submitted to it.  In this case, the
       Printer returns the 'server-error-not-accepting-jobs' status-code.

       This value is independent of the "printer-state" and
       "printer-state-reasons" attributes because its value does not affect
       the current Job; rather, it affects future Jobs.  This attribute,
       when 'false', causes the Printer to reject Jobs even when
       "printer-state" is 'idle' or, when 'true', causes the Printer to
       accept Jobs even when "printer-state" is 'stopped'.

    5.4.24.  queued-job-count (integer(0:MAX))

       This REQUIRED Printer attribute contains a count of the number of
       Jobs that are either 'pending', 'processing', 'pending-held', or
       'processing-stopped' and is set by the Printer.

    5.4.25.  printer-message-from-operator (text(127))

       This Printer attribute provides a message from an Operator,
       Administrator, or "intelligent" process to indicate to the End User
       information or status of the Printer, such as why it is unavailable
       or when it is expected to be available.

    5.4.26.  color-supported (boolean)

       This RECOMMENDED Printer attribute identifies whether the device is
       capable of any type of color printing at all, including highlight
       color.  All Document instructions having to do with color are
       embedded within the Document PDL, although IPP attributes can affect
       the rendering of those colors.

       Note: End Users are able to determine the nature and details of the
       color support by querying the "printer-more-info-manufacturer"
       Printer attribute.

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    5.4.27.  reference-uri-schemes-supported (1setOf uriScheme)

       This Printer attribute specifies which URI schemes are supported for
       use in the "document-uri" operation attribute of the Print-URI or
       Send-URI operations.  If a Printer supports these OPTIONAL
       operations, it MUST support the "reference-uri-schemes-supported"
       Printer attribute with at least the following URI scheme value:

       o  'ftp': The Printer will use an FTP 'get' operation as defined in
          [RFC959] using FTP URLs as defined by [RFC3986].

       The Printer MAY support other URI schemes (see Section 5.1.7).

    5.4.28.  pdl-override-supported (type2 keyword)

       This REQUIRED Printer attribute expresses the ability of a particular
       Printer implementation to override Document data instructions with
       IPP attributes.  The following 'keyword' values are defined in this
       document:

       o  'attempted': This value indicates that the Printer attempts to
          make the IPP attribute values take precedence over embedded
          instructions in the Document data; however, there is no guarantee.

       o  'not-attempted': This value indicates that the Printer makes no
          attempt to make the IPP attribute values take precedence over
          embedded instructions in the Document data.

       Appendix C contains a full description of how this attribute
       interacts with and affects other IPP attributes, especially the
       "ipp-attribute-fidelity" attribute.

    5.4.29.  printer-up-time (integer(1:MAX))

       This REQUIRED Printer attribute indicates the amount of time (in
       seconds) that this Printer instance has been up and running.  The
       value is a monotonically increasing value starting from 1 when the
       Printer is started up (initialized, booted, etc.).  This value is
       used to populate the Event Time Job Status attributes
       "time-at-creation", "time-at-processing", and "time-at-completed"
       (see Section 5.3.14).

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       If the Printer goes down at some value 'n' and comes back up, the
       implementation MAY:

       1.  know how long it has been down and resume at some value greater
           than 'n', or

       2.  restart from 1.

       In other words, if the device or devices that the Printer is
       representing are restarted or power-cycled, the Printer MAY continue
       counting this value or MAY reset this value to 1, depending on
       implementation.  However, if the Printer software ceases running and
       restarts without knowing the last value for "printer-up-time", the
       implementation MUST reset this value to 1.  If this value is reset
       and the Printer has persistent Jobs, the Printer MUST reset the
       "time-at-xxx (integer)" Event Time Job Status attributes according to
       Section 5.3.14.  An implementation MAY use both implementation
       alternatives, depending on warm versus cold start, respectively.

    5.4.30.  printer-current-time (dateTime|unknown)

       This RECOMMENDED Printer attribute indicates the current date and
       time.  This value is used to populate the Event Time Job Status
       attributes "date-time-at-creation", "date-time-at-processing", and
       "date-time-at-completed" (see Section 5.3.14).

       This value is obtained on a "best effort" basis and in practice does
       not have to be precise in order to be useful.  A Printer
       implementation sets the value of this attribute by obtaining the date
       and time via some implementation-dependent means, such as getting the
       value from a network time server, initialization at time of
       manufacture, or setting by an Administrator.  See [RFC3196] and
       [PWG5100.19] for examples.  If an implementation supports this
       attribute and the implementation knows that it has not yet been set,
       then the implementation MUST return the value of this attribute using
       the out-of-band 'unknown', meaning the value is not yet known.  See
       the beginning of Section 5.1.

       The time zone of this attribute might not be the time zone used by
       people located near the Printer or device.  The Client MUST NOT
       expect the time zone of any received 'dateTime' value to be in the
       time zone of the Client or in the time zone of the people located
       near the Printer.

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       The Client SHOULD display any dateTime attributes to the user in the
       Client's local time by converting the 'dateTime' value returned by
       the server to the time zone of the Client, rather than using the time
       zone returned by the Printer in attributes that use the 'dateTime'
       attribute syntax.

       Note: Prior versions of this document incorrectly specified the use
       of the 'no-value' out-of-band value when the current date and time
       had not been set.  The correct out-of-band value is 'unknown', since
       there is always an intrinsic current date and time.

    5.4.31.  multiple-operation-time-out (integer(1:MAX))

       This RECOMMENDED Printer attribute identifies the minimum time (in
       seconds) that the Printer waits for additional Send-Document or
       Send-URI operations to follow a still-open Job before taking any
       recovery actions, such as the ones indicated in Section 4.3.1.  If
       the Printer supports the Create-Job and Send-Document operations (see
       Sections 4.2.4 and 4.3.1), it MUST support this attribute.

       Printers SHOULD use a value between '60' and '240' (seconds).  An
       implementation MAY allow an Administrator to set this attribute by
       means not defined in this document.  If so, the Administrator MAY be
       able to set values outside this range.

    5.4.32.  compression-supported (1setOf type2 keyword)

       This REQUIRED Printer attribute identifies the set of supported
       compression algorithms for Document data.  Compression only applies
       to the Document data; compression does not apply to the encoding of
       the IPP operation itself.  The supported values are used to validate
       the Client-supplied "compression" operation attributes in Print-Job
       and Send-Document requests.

       Standard 'keyword' values defined in this document are:

       o  'none': no compression is used.

       o  'deflate': ZIP inflate/deflate compression technology described in
          RFC 1951 [RFC1951].

       o  'gzip': GNU zip compression technology described in RFC 1952
          [RFC1952].

       o  'compress': UNIX compression technology described in RFC 1977
          [RFC1977].

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    5.4.33.  job-k-octets-supported (rangeOfInteger(0:MAX))

       This Printer attribute specifies the upper and lower bounds of total
       sizes of Jobs in K octets, i.e., in units of 1024 octets.  The
       supported values are used to validate the Client-supplied
       "job-k-octets" operation attribute in Job Creation requests.  The
       corresponding Job Description attribute "job-k-octets" is defined in
       Section 5.3.17.1.

    5.4.34.  job-impressions-supported (rangeOfInteger(0:MAX))

       This RECOMMENDED Printer attribute specifies the upper and lower
       bounds for the number of Impressions per Job.  The supported values
       are used to validate the Client-supplied "job-impressions" operation
       attribute in Job Creation requests.  The corresponding Job
       Description attribute "job-impressions" is defined in
       Section 5.3.17.2.

    5.4.35.  job-media-sheets-supported (rangeOfInteger(1:MAX))

       This Printer attribute specifies the upper and lower bounds for the
       number of Media Sheets per Job.  The supported values are used to
       validate the Client-supplied "job-media-sheets" operation attribute
       in Job Creation requests.  The corresponding Job attribute
       "job-media-sheets" is defined in Section 5.3.17.3.

    5.4.36.  pages-per-minute (integer(0:MAX))

       This RECOMMENDED Printer attribute specifies the nominal number of
       pages per minute to the nearest whole number that can be generated by
       this Printer (e.g., simplex, black-and-white).  This attribute is
       informative, not a service guarantee.  Generally, it is the value
       used in the marketing literature to describe the speed of the device.

       A value of 0 indicates a device that takes more than two minutes to
       process a page.

    5.4.37.  pages-per-minute-color (integer(0:MAX))

       This RECOMMENDED Printer attribute specifies the nominal number of
       pages per minute to the nearest whole number that can be generated by
       this Printer when printing color (e.g., simplex, color).  For
       purposes of this attribute, the meaning of "color" is the same as
       that for the "color-supported" attribute; namely, the device is
       capable of any type of color printing at all, including highlight
       color.  This attribute is informative, not a service guarantee.
       Generally, it is the value used in the marketing literature to
       describe the color capabilities of this device.

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       A value of 0 indicates a device that takes more than two minutes to
       process a page in color.

       If a color device has several color modes, it MAY use the
       "pages-per-minute" value for this attribute that corresponds to the
       mode that produces the highest number.

       Printers that are black-and-white only MUST NOT support this
       attribute.  If this attribute is present, then the "color-supported"
       Printer Description attribute MUST be present and have a 'true'
       value.

       The values of the "pages-per-minute" and "pages-per-minute-color"
       attributes returned by the Get-Printer-Attributes operation MAY be
       affected by the "document-format" attribute supplied by the Client in
       the Get-Printer-Attributes request.  In other words, the
       implementation MAY have different speeds, depending on the Document
       format being processed.  See Section 4.2.5.1 ("Get-Printer-Attributes
       Request").

    6.  Conformance

       This section describes conformance issues and requirements.  This
       document introduces model entities such as objects, operations,
       attributes, attribute syntaxes, and attribute values.  The following
       sections describe the conformance requirements that apply to these
       model entities.

    6.1.  Client Conformance Requirements

       This section describes the conformance requirements for a Client (see
       Section 3.1), whether it be:

       1.  contained within software controlled by an End User, e.g.,
           activated by the "Print" menu item in an application that sends
           IPP requests, or

       2.  the print server component that sends IPP requests to either an
           Output Device or another "downstream" print server.

       A conforming Client supports all REQUIRED operations as defined in
       this document.  For each attribute included in an operation request,
       a conforming Client MUST supply a value whose type and value syntax
       conforms to the requirements specified in Sections 4 and 5 of this
       document.  A conforming Client MAY supply any Standards Track
       extensions and/or vendor extensions in an operation request, as long
       as the extensions meet the requirements in Section 7.

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       While this document does not define conformance requirements for the
       user interfaces provided by IPP Clients or their applications, best
       practices for user interfaces are defined in [PWG5100.19].

       A Client MUST be able to accept any of the attribute syntaxes defined
       in Section 5.1, including their full range, that can be returned to
       it in a response from a Printer.  In particular, for each attribute
       that the Client supports whose attribute syntax is 'text', the Client
       MUST accept and process both the 'textWithoutLanguage' and
       'textWithLanguage' forms.  Similarly, for each attribute that the
       Client supports whose attribute syntax is 'name', the Client MUST
       accept and process both the 'nameWithoutLanguage' and
       'nameWithLanguage' forms.  For presentation purposes, truncation of
       long attribute values is not recommended.  A recommended approach
       would be for the Client implementation to allow the user to scroll
       through long attribute values.

       A response MAY contain attribute groups, attributes, attribute
       syntaxes, values, and status-code values that the Client does not
       expect.  Therefore, a Client implementation MUST gracefully handle
       such responses and not refuse to interoperate with a conforming
       Printer that is returning Standards Track extensions or vendor
       extensions, including attribute groups, attributes, attribute
       syntaxes, attribute values, status-code values, and out-of-band
       attribute values that conform to Section 7.  Clients can choose to
       ignore any parameters, attribute groups, attributes, attribute
       syntaxes, or values that they do not understand.

       While a Client is sending data to a Printer, it SHOULD do its best to
       prevent a channel from being closed by a lower layer when the channel
       is blocked (i.e., flow-controlled off) for whatever reason, e.g.,
       'out of paper' or 'Job ahead hasn't freed up enough memory'.
       However, the layer that launched the print submission (e.g., an
       End User) MAY close the channel in order to cancel the Job.  When a
       Client closes a channel, a Printer MAY print all or part of the
       received portion of the Document.  See the Encoding and Transport
       document [RFC8010] for more details.

       A Client MUST support Client Authentication as defined in [RFC8010].
       A Client SHOULD support Operation Privacy and Server Authentication
       as defined in [RFC8010].  See also Section 9 of this document.

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    6.2.  IPP Object Conformance Requirements

       This section specifies the conformance requirements for conforming
       implementations of IPP objects (see Section 3).  These requirements
       apply to an IPP object whether it is:

       1)  an (embedded) device component that accepts IPP requests and
           controls the device, or

       2)  a component of a print server that accepts IPP requests (where
           the print server controls one or more networked devices using IPP
           or other protocols).

    6.2.1.  Objects

       Conforming implementations MUST implement all of the model objects as
       defined in this document in the indicated sections:

       Section 3.1 - Printer Object

       Section 3.2 - Job Object

    6.2.2.  Operations

       Conforming IPP object implementations MUST implement all of the
       REQUIRED model operations, including REQUIRED responses, as defined
       in this document in the indicated sections.  Table 20 lists the
       operations for a Printer, while Table 21 lists the operations for
       a Job.

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             +----------------------------------------+-------------+
             | Operation                              | Conformance |
             +----------------------------------------+-------------+
             | Print-Job (Section 4.2.1)              | REQUIRED    |
             +----------------------------------------+-------------+
             | Print-URI (Section 4.2.2)              | OPTIONAL    |
             +----------------------------------------+-------------+
             | Validate-Job (Section 4.2.3)           | REQUIRED    |
             +----------------------------------------+-------------+
             | Create-Job (Section 4.2.4)             | RECOMMENDED |
             +----------------------------------------+-------------+
             | Get-Printer-Attributes (Section 4.2.5) | REQUIRED    |
             +----------------------------------------+-------------+
             | Get-Jobs (Section 4.2.6)               | REQUIRED    |
             +----------------------------------------+-------------+
             | Pause-Printer (Section 4.2.7)          | OPTIONAL    |
             +----------------------------------------+-------------+
             | Resume-Printer (Section 4.2.8)         | OPTIONAL    |
             +----------------------------------------+-------------+
             | Purge-Jobs (Section 4.2.9)             | SHOULD NOT  |
             +----------------------------------------+-------------+

             Table 20: Conformance Requirements for Printer Operations

               +------------------------------------+-------------+
               | Operation                          | Conformance |
               +------------------------------------+-------------+
               | Send-Document (Section 4.3.1)      | RECOMMENDED |
               +------------------------------------+-------------+
               | Send-URI (Section 4.3.2)           | RECOMMENDED |
               +------------------------------------+-------------+
               | Cancel-Job (Section 4.3.3)         | REQUIRED    |
               +------------------------------------+-------------+
               | Get-Job-Attributes (Section 4.3.4) | REQUIRED    |
               +------------------------------------+-------------+
               | Hold-Job (Section 4.3.5)           | OPTIONAL    |
               +------------------------------------+-------------+
               | Release-Job (Section 4.3.6)        | OPTIONAL    |
               +------------------------------------+-------------+
               | Restart-Job (Section 4.3.7)        | SHOULD NOT  |
               +------------------------------------+-------------+

               Table 21: Conformance Requirements for Job Operations

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       Conforming IPP objects MUST support all REQUIRED operation attributes
       and all values of such attributes if so indicated in the description.
       Conforming IPP objects MUST ignore all unsupported or unknown
       operation attributes or Operation Attributes groups received in a
       request but MUST reject a request that contains a supported operation
       attribute that contains an unsupported value.

       Conforming IPP objects MAY return operation responses that contain
       attribute groups, attribute names, attribute syntaxes, attribute
       values, and status-code values that are extensions to this
       specification.  The additional attribute groups MAY occur in any
       order.

       The following section on object attributes specifies the support
       required for object attributes.

    6.2.3.  IPP Object Attributes

       Conforming IPP objects MUST support all of the REQUIRED object
       attributes, as defined in this document in the indicated sections.

       If an object supports an attribute, it MUST support only those values
       specified in this document or through the extension mechanism
       described in Section 6.2.5.  It MAY support any non-empty subset of
       these values.  That is, it MUST support at least one of the specified
       values and at most all of them.

    6.2.4.  Versions

       IPP/1.1 Clients MUST meet the conformance requirements for Clients
       specified in this document and [RFC8010].  IPP/1.1 Clients MUST be
       capable of sending requests containing a "version-number" parameter
       with a value of '1.1'.

       IPP/1.1 Printer and Job objects MUST meet the conformance
       requirements for IPP objects specified in this document and
       [RFC8010].  IPP/1.1 objects MUST accept requests containing a
       "version-number" parameter with a '1.1' value or reject the request
       if the operation is not supported.

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       It is beyond the scope of this specification to mandate conformance
       with other IPP versions.  However, IPP was deliberately designed to
       make supporting different versions easy.  IPP/1.1 Printer
       implementations MUST:

       o  decode and process any well-formed IPP/1.1 request, and

       o  respond appropriately with a response containing the same
          "version-number" parameter value used by the Client in the
          request.

       IPP/1.1 Client implementations MUST:

       o  decode and process any well-formed IPP/1.1 response.

       IPP Clients SHOULD try supplying alternate version numbers if they
       receive a 'server-error-version-not-supported' error in a response.

    6.2.5.  Extensions

       A conforming IPP object MAY support Standards Track extensions and
       vendor extensions, as long as the extensions meet the requirements
       specified in Section 7.

       For each attribute included in an operation response, a conforming
       IPP object MUST return a value whose type and value syntax conforms
       to the requirements specified in Sections 4 and 5 of this document.

    6.2.6.  Attribute Syntaxes

       An IPP object MUST be able to accept any of the attribute syntaxes
       defined in Section 5.1, including their full range, in any operation
       in which a Client can supply attributes or the Administrator can
       configure attributes (by means outside the scope of this IPP/1.1
       document).  In particular, for each attribute that the IPP object
       supports whose attribute syntax is 'text', the IPP object MUST accept
       and process both the 'textWithoutLanguage' and 'textWithLanguage'
       forms.  Similarly, for each attribute that the IPP object supports
       whose attribute syntax is 'name', the IPP object MUST accept and
       process both the 'nameWithoutLanguage' and 'nameWithLanguage' forms.
       Furthermore, an IPP object MUST return attributes to the Client in
       operation responses that conform to the syntaxes specified in
       Section 5.1, including their full range if supplied previously by a
       Client.

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    6.2.7.  Security

       An IPP Printer implementation SHOULD contain support for Client
       Authentication as defined in the IPP/1.1 Encoding and Transport
       document [RFC8010].  A Printer implementation MAY allow an
       Administrator to configure the Printer so that all, some, or none of
       the users are authenticated.  See also Section 9 of this document.

       An IPP Printer implementation SHOULD contain support for Operation
       Privacy and Server Authentication as defined in [RFC8010].  A Printer
       implementation MAY allow an Administrator to configure the degree of
       support for Operation Privacy and Server Authentication.  See also
       Section 9 of this document.

       Security MUST NOT be compromised when a Client supplies a lower
       "version-number" parameter in a request.  For example, if a Printer
       conforming to IPP/1.1 accepts version '1.0' requests and is
       configured to enforce Digest Authentication, it MUST do the same for
       a version '1.0' request.

    6.3.  Charset and Natural Language Requirements

       All Clients and IPP objects MUST support the 'utf-8' charset as
       defined in Section 5.1.8.

       IPP objects MUST be able to accept any Client request that correctly
       uses the "attributes-natural-language" operation attribute or the
       Natural Language Override mechanism on any individual attribute
       whether or not the natural language is supported by the IPP object.
       If an IPP object supports a natural language, then it MUST be able to
       translate (perhaps by table lookup) all generated 'text' or 'name'
       attribute values into one of the supported languages (see
       Section 4.1.4).

    Sweet & McDonald             Standards Track                  [Page 172]

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    7.  IANA Considerations

       This section describes the procedures for defining Standards Track
       and vendor extensions to this document.  This affects the following
       subregistries of the IANA IPP registry:

       1.  Objects

       2.  Attributes

       3.  Keyword Attribute Values

       4.  Enum Attribute Values

       5.  Attribute Group Tags

       6.  Out-of-Band Attribute Value Tags

       7.  Attribute Syntaxes

       8.  Operations

       9.  Status-Code Values

       Extensions registered for use with IPP are OPTIONAL for Client and
       IPP object conformance to the IPP/1.1 Model and Semantics document
       (this document).

       These extension procedures are aligned with the guidelines as set
       forth in "Guidelines for Writing an IANA Considerations Section in
       RFCs" [RFC5226].  Appendix A describes how to propose new
       registrations for consideration.  IANA will reject registration
       proposals that leave out required information or do not follow the
       appropriate format described in Appendix A.  The IPP/1.1 Model and
       Semantics document can also be extended by an appropriate
       Standards Track document that specifies any of the above extensions.

       The IANA policy (using terms defined in [RFC5226]) for all extensions
       is Specification Required, Expert Review, or First Come First Served
       as documented in the following subsections.  Registrations submitted
       to IANA are forwarded to the IPP Designated Expert(s) who reviews the
       proposal on a mailing list that the Designated Expert(s) keeps for
       this purpose.  Initially, that list is the mailing list used by the
       PWG IPP WG:

          ipp@pwg.org

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       The IPP Designated Expert(s) is appointed by the IESG Area Director
       responsible for IPP, according to [RFC5226].

       In addition, the IANA-PRINTER-MIB [RFC3805] has been updated to
       reference this document; the current version is available from
       <http://www.iana.org>.

    7.1.  Object Extensions

       The IANA policy (using terms defined in [RFC5226]) for object
       extensions was formerly Expert Review; this document changes the
       policy to Specification Required.

    7.2.  Attribute Extensibility

       Since attribute names are type2 keywords (see Section 5.1.4), the
       IANA policy (using terms defined in [RFC5226]) for attribute
       extensions is Expert Review.

       For vendor attribute extensions, implementors SHOULD use keywords
       with a suitable distinguishing prefix such as 'smiNNN-' where NNN is
       an SMI Private Enterprise Number (PEN) [IANA-PEN].  For example, if
       the company Example Corp. had obtained the SMI PEN 32473, then a
       vendor attribute 'foo' would be 'smi32473-foo'.

          Note: Prior versions of this document recommended using a fully
          qualified domain name [RFC1035] as the prefix (e.g.,
          'example.com-foo'), and many IPP implementations have also used
          reversed domain names (e.g., 'com.example-foo').  Domain names
          have proven problematic due to the length of some domain names,
          parallel use of country-specific domain names (e.g.,
          'example.co.jp-foo'), and changes in ownership of domain names.

       If a new Printer attribute is defined and its values can be affected
       by a specific Document format, its specification needs to contain the
       following sentence:

          "The value of this attribute returned in a Get-Printer-Attributes
          response MAY depend on the "document-format" attribute supplied
          (see Section 4.2.5.1) of the IPP/1.1 Model and Semantics
          document."

       If the specification does not, then its value in the
       Get-Printer-Attributes response MUST NOT depend on the
       "document-format" attribute supplied in the request.

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       When a new Job Template attribute is registered, the value of the
       Printer attributes MAY vary with "document-format" supplied in the
       request without the specification having to indicate so.

    7.3.  Keyword Extensibility

       The IANA policy (using terms defined in [RFC5226]) for type1 keyword
       extensions is Specification Required.  The IANA policy for type2
       keyword extensions is Expert Review.  The IANA policy for vendor
       keyword extensions is First Come First Served.  Only attributes using
       the type1 and type2 keyword syntax can be registered in the IANA IPP
       registry.

          Note: The type1 or type2 prefix on the basic attribute syntax is
          provided only to communicate the IANA policy required for
          registration and is not represented in IPP messages.  Both type1
          and type2 'keyword' values are represented using the same
          'keyword' value tag.

       For type1 and type2 keywords, the proposer includes the name of the
       keyword in the registration proposal, and the name is part of the
       technical review.

       For vendor keyword extensions, implementors SHOULD either:

       a.  follow attribute-specific guidance such as the guidance defined
           in [PWG5101.1], or

       b.  use keywords with a suitable distinguishing prefix, such as
           'smiNNN-' where NNN is an SMI Private Enterprise Number (PEN)
           [IANA-PEN].

       For example, if the company Example Corp. had obtained the
       SMI PEN 32473, then a vendor keyword 'foo' would be 'smi32473-foo'.

          Note: Prior versions of this document recommended using a fully
          qualified domain name [RFC1035] as the prefix (e.g.,
          'example.com-foo'), and many IPP implementations have also used
          reversed domain names (e.g., 'com.example-foo').  Domain names
          have proven problematic due to the length of some domain names,
          parallel use of country-specific domain names (e.g.,
          'example.co.jp-foo'), and changes in ownership of domain names.

       When a type2 keyword extension is approved, the IPP Designated
       Expert(s) becomes the point of contact for any future maintenance
       that might be required for that registration.

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    7.4.  Enum Extensibility

       The IANA policy (using terms defined in [RFC5226]) for type1 enum
       extensions is Specification Required.  The IANA policy for type2 enum
       extensions is Expert Review.  The IANA policy for vendor enum
       extensions is First Come First Served.  Only attributes using the
       type1 and type2 enum syntax can be registered in the IANA IPP
       registry.

          Note: The type1 or type2 prefix on the basic attribute syntax is
          provided only to communicate the IANA policy required for
          registration and is not represented in IPP messages.  Both type1
          and type2 enum values are represented using the same enum
          value tag.

       For vendor enum extensions, implementors MUST use values in the
       reserved integer range, which is 0x40000000 to 0x7fffffff.
       Implementors SHOULD consult with the IPP Designated Expert(s) to
       reserve vendor extension value(s) for their usage.

       When a type1 or type2 enum extension is approved, the IPP Designated
       Expert(s), in consultation with IANA, assigns the next available enum
       number for each enum value.

       When a type2 enum extension is approved, the IPP Designated Expert(s)
       becomes the point of contact for any future maintenance that might be
       required for that registration.

    7.5.  Attribute Group Extensibility

       The IANA policy (using terms defined in [RFC5226]) for attribute
       group extensions was formerly Expert Review; this document changes
       the policy to Specification Required.

       For attribute groups, the IPP Designated Expert(s), in consultation
       with IANA, assigns the next attribute group tag code in the
       appropriate range as specified in [RFC8010].

    7.6.  Out-of-Band Attribute Value Extensibility

       The IANA policy (using terms defined in [RFC5226]) for out-of-band
       attribute value extensions was formerly Expert Review; this document
       changes the policy to Specification Required.

       For out-of-band attribute value tags, the IPP Designated Expert(s),
       in consultation with IANA, assigns the next out-of-band attribute
       value tag code in the appropriate range as specified in [RFC8010].

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    7.7.  Attribute Syntax Extensibility

       The IANA policy (using terms defined in [RFC5226]) for attribute
       syntax extensions was formerly Expert Review; this document changes
       the policy to Specification Required.  The IANA policy for vendor
       attribute syntax extensions (tags 0x40000000 to 0x7fffffff) is First
       Come First Served.  Only attribute syntaxes in the range of
       0x00000000 to 0x3fffffff can be registered in the IANA IPP registry.

       For vendor attribute syntax extensions, implementors MUST use values
       in the reserved integer range, which is 0x40000000 to 0x7fffffff.
       Implementors SHOULD consult with the IPP Designated Expert(s) to
       reserve vendor extension value(s) for their usage.

       For registered attribute syntaxes, the IPP Designated Expert(s), in
       consultation with IANA, assigns the next attribute syntax tag in the
       appropriate range as specified in [RFC8010].

    7.8.  Operation Extensibility

       The IANA policy (using terms defined in [RFC5226]) for operation
       extensions is Expert Review.  The IANA policy for vendor operation
       extensions (values 0x4000 to 0x7fff) is First Come First Served.
       Only operation codes in the range of 0x0000 to 0x3fff can be
       registered in the IANA IPP registry.

       For vendor operation extensions, implementors MUST use values in the
       reserved integer range, which is 0x4000 to 0x7fff.  Implementors
       SHOULD consult with the IPP Designated Expert(s) to reserve vendor
       extension value(s) for their usage.

       For registered operation extensions, the IPP Designated Expert(s), in
       consultation with IANA, assigns the next "operation-id" code as
       specified in Section 5.4.15.

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    7.9.  Status-Code Extensibility

       The IANA policy (using terms defined in [RFC5226]) for status-code
       extensions is Expert Review.  The IANA policy for vendor status-code
       extensions (codes 0x0n80 to 0x0nff, for n = 0 to 5) is First Come
       First Served.  Only status-code values in the range of 0x0n00 to
       0x0n7f can be registered in the IANA IPP registry.

       The status-code values are allocated in ranges as specified in
       Appendix B for each status-code class:

       "informational" - Request received, continuing process

       "successful" - The action was successfully received, understood, and
       accepted

       "redirection" - Further action is taken in order to complete the
       request

       "client-error" - The request contains bad syntax or cannot be
       fulfilled

       "server-error" - The IPP object failed to fulfill an apparently valid
       request

       For vendor operation status-code extensions, implementors MUST use
       the top of each range (0x0n80 to 0x0nff) as specified in Appendix B.
       Implementors SHOULD consult with the IPP Designated Expert(s) to
       reserve vendor extension value(s) for their usage.

       For registered operation status-code values, the IPP Designated
       Expert(s), in consultation with IANA, assigns the next status-code in
       the appropriate class range as specified in Appendix B.

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    8.  Internationalization Considerations

       Some of the attributes have values that are text strings and names
       that are intended for human understanding rather than machine
       understanding (see the 'text' and 'name' attribute syntaxes in
       Sections 5.1.2 and 5.1.3).

       In each operation request, the Client

       o  identifies the charset and natural language of the request that
          affects each supplied 'text' and 'name' attribute value, and

       o  requests the charset and natural language for attributes returned
          by the IPP object in operation responses (as described in
          Section 4.1.4.1).

       In addition, the Client MAY separately and individually identify the
       Natural Language Override of a supplied 'text' or 'name' attribute
       using the 'textWithLanguage' and 'nameWithLanguage' techniques
       described in Sections 5.1.2.2 and 5.1.3.2, respectively.

       All IPP objects MUST support the UTF-8 [RFC3629] charset in all
       'text' and 'name' attributes supported.  If an IPP object supports
       more than the UTF-8 charset, the object MUST convert between them in
       order to return the requested charset to the Client according to
       Section 4.1.4.2.  If an IPP object supports more than one natural
       language, the object SHOULD return 'text' and 'name' values in the
       natural language requested where those values are generated by the
       Printer (see Section 4.1.4.1).

       For Printers that support multiple charsets and/or multiple natural
       languages in 'text' and 'name' attributes, different Jobs might have
       been submitted in differing charsets and/or natural languages.  All
       responses MUST be returned in the charset requested by the Client.
       However, the Get-Jobs operation uses the 'textWithLanguage' and
       'nameWithLanguage' mechanisms to identify the differing natural
       languages with each Job attribute returned.

       The Printer also has configured charset and natural language
       attributes.  The Client can query the Printer to determine the list
       of charsets and natural languages supported by the Printer and what
       the Printer's configured values are.  See the "charset-configured",
       "charset-supported", "natural-language-configured", and
       "generated-natural-language-supported" Printer Description attributes
       for more details.

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       The "charset-supported" attribute identifies the supported charsets.
       If a charset is supported, the IPP object MUST be capable of
       converting to and from that charset into any other supported charset.
       In many cases, an IPP object will support only one charset, and it
       MUST be the UTF-8 charset.

       The "charset-configured" attribute identifies the one supported
       charset that is the native charset, given the current configuration
       of the IPP object (Administrator defined).

       The "generated-natural-language-supported" attribute identifies the
       set of supported natural languages for generated messages; it is not
       related to the set of natural languages that MUST be accepted for
       Client-supplied 'text' and 'name' attributes.  For Client-supplied
       'text' and 'name' attributes, an IPP object MUST accept ALL supplied
       natural languages.  For example, if a Client supplies a Job name that
       is in 'fr-ca' but the Printer only generates 'en-us', the Printer
       object MUST still accept the Job name value.

       The "natural-language-configured" attribute identifies the one
       supported natural language for generated messages that is the native
       natural language, given the current configuration of the IPP object
       (Administrator defined).

       Attributes of types 'text' and 'name' are populated from different
       sources.  These attributes can be categorized into the following
       groups (depending on the source of the attribute):

       1.  Some attributes are supplied by the Client (e.g., the
           Client-supplied "job-name", "document-name", and
           "requesting-user-name" operation attributes along with the
           corresponding Job's "job-name" and "job-originating-user-name"
           attributes).  The IPP object MUST accept these attributes in any
           natural language no matter what the set of supported languages
           for generated messages.

       2.  Some attributes are supplied by the Administrator (e.g., the
           Printer's "printer-name" and "printer-location" attributes).
           These can also be in any natural language.  If the natural
           language for these attributes is different than what a Client
           requests, then they MUST be reported using the Natural Language
           Override mechanism.

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       3.  Some attributes are supplied by the device manufacturer (e.g.,
           the Printer's "printer-make-and-model" attribute).  These can
           also be in any natural language.  If the natural language for
           these attributes is different than what a Client requests, then
           they MUST be reported using the Natural Language Override
           mechanism.

       4.  Some attributes are supplied by the Operator (e.g., the Job's
           "job-message-from-operator" attribute).  These can also be in any
           natural language.  If the natural language for these attributes
           is different than what a Client requests, then they MUST be
           reported using the Natural Language Override mechanism.

       5.  Some attributes are generated by the IPP object (e.g., the Job's
           "job-state-message" attribute, the Printer's
           "printer-state-message" attribute, and the "status-message"
           operation attribute).  These attributes can only be in one of the
           "generated-natural-language-supported" natural languages.  If a
           Client requests some natural language for these attributes other
           than one of the supported values, the IPP object SHOULD respond
           using the value of the "natural-language-configured" attribute
           (using the Natural Language Override mechanism if needed).

       The 'text' and 'name' attributes specified in this version of this
       document (additional ones will be registered according to the
       procedures in Section 7) are shown in Table 22.

       +-----------------------------------+-------------------------------+
       | Attributes                        | Source                        |
       +-----------------------------------+-------------------------------+
       | Operation Attributes:             |                               |
       |                                   |                               |
       | job-name (name)                   | Client                        |
       | document-name (name)              | Client                        |
       | requesting-user-name (name)       | Client                        |
       | status-message (text)             | Job or Printer                |
       | detailed-status-message (text)    | Job or Printer (note 1)       |
       | document-access-error (text)      | Job or Printer (note 1)       |
       |                                   |                               |
       | Job Template Attributes:          |                               |
       |                                   |                               |
       | job-hold-until (keyword | name)   | Client matches Administrator- |
       |                                   | configured                    |
       | job-hold-until-default (keyword | | Client matches Administrator- |
       | name)                             | configured                    |
       | job-hold-until-supported (keyword | Client matches Administrator- |
       | | name)                           | configured                    |

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       | job-sheets (keyword | name)       | Client matches Administrator- |
       |                                   | configured                    |
       | job-sheets-default (keyword |     | Client matches Administrator- |
       | name)                             | configured                    |
       | job-sheets-supported (keyword |   | Client matches Administrator- |
       | name)                             | configured                    |
       | media (keyword | name)            | Client matches Administrator- |
       |                                   | configured                    |
       | media-default (keyword | name)    | Client matches Administrator- |
       |                                   | configured                    |
       | media-supported (keyword | name)  | Client matches Administrator- |
       |                                   | configured                    |
       | media-ready (keyword | name)      | Client matches Administrator- |
       |                                   | configured                    |
       |                                   |                               |
       | Job Description Attributes:       |                               |
       |                                   |                               |
       | job-name (name)                   | Client or Printer             |
       | job-originating-user-name (name)  | Printer                       |
       | job-state-message (text)          | Job or Printer                |
       | output-device-assigned            | Administrator                 |
       | (name(127))                       |                               |
       | job-message-from-operator         | Operator                      |
       | (text(127))                       |                               |
       | job-detailed-status-messages      | Job or Printer (note 1)       |
       | (1setOf text)                     |                               |
       | job-document-access-errors        | Job or Printer (note 1)       |
       | (1setOf text)                     |                               |
       |                                   |                               |
       | Printer Description Attributes:   |                               |
       |                                   |                               |
       | printer-name (name(127))          | Administrator                 |
       | printer-location (text(127))      | Administrator                 |
       | printer-info (text(127))          | Administrator                 |
       | printer-make-and-model            | Administrator or manufacturer |
       | (text(127))                       |                               |
       | printer-state-message (text)      | Printer                       |
       | printer-message-from-operator     | Operator                      |
       | (text(127))                       |                               |
       +-----------------------------------+-------------------------------+

                      Table 22: 'text' and 'name' Attributes

       Note 1: Neither the Printer nor the Client localizes these message
       attributes, since they are intended for use by the Administrator or
       other experienced technical persons.

    Sweet & McDonald             Standards Track                  [Page 182]

    RFC 8011              IPP/1.1: Model and Semantics          January 2017

    9.  Security Considerations

       It is difficult to anticipate the security risks that might exist in
       any given IPP environment.  For example, if IPP is used within a
       given small business over a private LAN with physical security, the
       risks of exposing Document data can be low enough that the business
       will choose not to use encryption on that data.  However, if the
       connection between the Client and the IPP object is over a public
       network, the Client can protect the content of the information during
       transmission through the network with encryption.

       Furthermore, the value of the information being printed can vary from
       one IPP environment to the next.  Printing payroll checks, for
       example, would have a different value than printing public
       information from a file.  There is also the possibility of denial-of-
       service attacks, but denial-of-service attacks against printing
       resources are not well understood, and there are no published
       precedents regarding this scenario.

       Once the authenticated identity of the requester has been supplied to
       the IPP object, the object uses that identity to enforce any
       authorization policy that might be in place.  For example, one site's
       policy might be that only the Job owner is allowed to cancel a Job.
       The details and mechanisms to set up a particular access control
       policy are not part of this document and are typically established
       via some other type of administrative or access control framework.
       However, there are operation status-code values that allow an IPP
       server to return information back to a Client about any potential
       access control violations for an IPP object.

       During a Job Creation request, the Client's identity is recorded in
       the Job object in an implementation-defined attribute.  This
       information can be used to verify a Client's identity for subsequent
       operations on that Job object in order to enforce any access control
       policy that might be in effect.  See Section 9.3 below for more
       details.  This and other information stored in the Job object can
       also be considered personal or sensitive in nature and can be
       filtered out as part of a configured privacy policy (Section 9.4).

       Since the security levels or the specific threats that an
       Administrator can be concerned with cannot be anticipated, IPP
       implementations MUST be capable of operating with different security
       mechanisms and security policies as required by the individual
       installation.  Security policies might vary from very strong to very
       weak, or to none at all, and corresponding security mechanisms will
       be required.

    Sweet & McDonald             Standards Track                  [Page 183]

    RFC 8011              IPP/1.1: Model and Semantics          January 2017

    9.1.  Security Scenarios

       The following sections describe specific security attacks for IPP
       environments.  Where examples are provided, they are illustrative of
       the environment and not an exhaustive set.

    9.1.1.  Client and Server in the Same Security Domain

       This environment is typical of internal networks where traditional
       office workers print the output of personal productivity applications
       on shared workgroup Printers, or where batch applications print their
       output on large production Printers.  Although the identity of the
       user has been authenticated and can be trusted in this environment, a
       user might want to protect the content of a Document against such
       attacks as eavesdropping, replaying, or tampering by using a secure
       transport such as TLS [RFC5246].

    9.1.2.  Client and Server in Different Security Domains

       Examples of this environment include printing a Document created by
       the Client on a publicly available Printer, such as at a commercial
       print shop, or printing a Document remotely on a business associate's
       Printer.  This latter operation is functionally equivalent to sending
       the Document to the business associate as a facsimile.  Printing
       sensitive information on a Printer in a different security domain
       requires strong security measures.  In this environment,
       authentication of the Printer is required as well as protection
       against unauthorized use of print resources.  Since the Document
       crosses security domains, protection against eavesdropping and
       Document tampering is also required.  It will also be important in
       this environment to protect Printers against "spamming" and malicious
       Document content -- authentication and Document data pre-scanning can
       be used to minimize those threats.

    9.1.3.  Print by Reference

       When the Document is not stored on the Client, printing can be done
       by reference.  That is, the print request can contain a reference, or
       pointer, to the Document instead of the actual Document itself -- see
       Sections 4.2.2 and 4.3.2.  Standard methods currently do not exist
       for remote entities to "assume" the credentials of a Client for
       forwarding requests to a third party.  It is anticipated that print
       by reference will be used to access "public" Documents.  Note that
       sophisticated methods for authenticating "proxies" are beyond the
       scope of this IPP/1.1 document.  Because Printers typically process
       Jobs serially, print by reference is not seen as a serious denial-of-
       service threat to the referenced servers.

    Sweet & McDonald             Standards Track                  [Page 184]

    RFC 8011              IPP/1.1: Model and Semantics          January 2017

    9.2.  URIs in Operation, Job, and Printer Attributes

       The "printer-uri-supported" attribute contains the Printer's URI(s).
       Its companion attribute, "uri-security-supported", identifies the
       security mechanism used for each URI listed in the
       "printer-uri-supported" attribute.  For each Printer operation
       request, a Client MUST supply only one URI in the "printer-uri"
       operation attribute.  In other words, even though the Printer
       supports more than one URI, the Client only interacts with the
       Printer using one of its URIs.  This duality is not needed for Job
       objects, since Printers will act as the "factory" for Job objects and
       a given Printer will, depending on the Printer's security
       configuration, generate the correct URI for new Job objects.

    9.3.  URIs for Each Authentication Mechanism

       Each URI has an authentication mechanism associated with it.  If the
       URI is the "i-th" element of "printer-uri-supported", then the
       authentication mechanism is the "i-th" element of
       "uri-authentication-supported".  For a list of possible
       authentication mechanisms, see Section 5.4.2.

       The Printer uses an authentication mechanism to determine the name of
       the user performing an operation.  This user is called the
       "authenticated user".  The credibility of authentication depends on
       the mechanism that the Printer uses to obtain the user's name.  When
       the authentication mechanism is 'none', all authenticated users are
       'anonymous'.

       During Job Creation requests, the Printer initializes the value of
       the "job-originating-user-name" attribute (see Section 5.3.6) to be
       the authenticated user.  The authenticated user in this case is
       called the "Job owner".

       If an implementation can be configured to support more than one
       authentication mechanism (see Section 5.4.2), then it MUST implement
       rules for determining equality of authenticated user names that have
       been authenticated via different authentication mechanisms.  One
       possible policy is that identical names that are authenticated via
       different mechanisms are different.  For example, a user can cancel
       his Job only if he uses the same authentication mechanism for both
       Cancel-Job and Print-Job.  Another policy is that identical names
       that are authenticated via different mechanisms are the same if the
       authentication mechanism for the later operation is not less strong
       than the authentication mechanism for the earlier Job Creation
       operation.  For example, a user can cancel his Job only if he uses
       the same or stronger authentication mechanism for Cancel-Job and
       Print-Job.  With this second policy, a Job submitted via

    Sweet & McDonald             Standards Track                  [Page 185]

    RFC 8011              IPP/1.1: Model and Semantics          January 2017

       'requesting-user-name' authentication could be canceled via 'digest'
       authentication.  With the first policy, the Job could not be canceled
       in this way.

       A Client is able to determine the authentication mechanism used to
       create a Job.  It is the "i-th" value of the Printer's
       "uri-authentication-supported" attribute (see Section 5.4.2),
       where "i" is the index of the element of the Printer's
       "printer-uri-supported" attribute (see Section 5.4.1) equal to the
       Job's "job-printer-uri" attribute (see Section 5.3.3).

    9.4.  Restricted Queries

       In many IPP operations, a Client supplies a list of attributes to be
       returned in the response.  For security reasons, an IPP object can be
       configured not to return all attributes (or all values) that a Client
       requests.  The Job attributes returned MAY depend on whether the
       requesting user is the same as the user that submitted the Job.  The
       IPP object MAY even return none of the requested attributes.  In such
       cases, the status returned is the same as if the object had returned
       all requested attributes.  The Client cannot tell by such a response
       whether the requested attribute was present or absent in the object.

    9.5.  Operations Performed by Operators and Administrators

       For the three Printer operations Pause-Printer, Resume-Printer, and
       Purge-Jobs (see Sections 4.2.7, 4.2.8, and 4.2.9), the requesting
       user is intended to be an Operator or Administrator of the Printer
       (see Section 1).  Otherwise, the IPP Printer MUST reject the
       operation and return 'client-error-forbidden',
       'client-error-not-authenticated', or 'client-error-not-authorized'
       as appropriate.  For operations on Jobs, the requesting user is
       intended to be the Job owner or can be an Operator or Administrator
       of the Printer.  The means for authorizing an Operator or
       Administrator of the Printer are not specified in this document.

    9.6.  Queries on Jobs Submitted Using Non-IPP Protocols

       If the device that an IPP Printer is representing is able to accept
       Jobs using other Job submission protocols in addition to IPP, such an
       implementation SHOULD at least allow such "foreign" Jobs to be
       queried using Get-Jobs returning "job-id" and "job-uri" as 'unknown'.
       Such an implementation MAY support all of the same IPP Job attributes
       as for IPP Jobs.  The IPP object returns the 'unknown' out-of-band
       value for any requested attribute of a foreign Job that is supported
       for IPP Jobs but not for foreign Jobs.

    Sweet & McDonald             Standards Track                  [Page 186]

    RFC 8011              IPP/1.1: Model and Semantics          January 2017

       IPP Printers SHOULD also generate "job-id" and "job-uri" values for
       such foreign Jobs, if possible, so that they can be targets of other
       IPP operations, such as Get-Job-Attributes and Cancel-Job.  Such an
       implementation also needs to deal with the problem of authentication
       of such foreign Jobs.  One approach would be to treat all such
       foreign Jobs as belonging to users other than the user of the IPP
       Client.  Another approach would be for the foreign Job to belong to
       'anonymous' -- then only authenticated Operators or Administrators of
       the IPP Printer could query the foreign Jobs with an IPP request.
       Alternatively, if the security policy is to allow users to query
       other users' Jobs, then the foreign Jobs would also be visible to an
       End User IPP Client using Get-Jobs and Get-Job-Attributes.

    10.  Changes since RFC 2911

       The following changes have been made since RFC 2911:

       o  Errata ID 364: Fixed range of "redirection" status-code values (to
          0x03xx).

       o  Errata ID 694: Fixed range of vendor status-code values (0x0n80 to
          0x0nff).

       o  Errata ID 3072: Reworded multiple-document-handling definition,
          since it also applies to Jobs with a single Document and is the
          only interoperable way to request uncollated copies.

       o  Errata ID 3365: Fixed bad 'nameWithLanguage' maximum length by
          referencing the 'nameWithoutLanguage' section (i.e.,
          Section 5.1.3.1).

       o  Errata ID 4173: Fixed range of vendor operation codes (0x4000 to
          0x7fff).

       o  Updated obsoleted RFC references.

       o  Changed the IPP/1.1 Implementor's Guide reference to RFC 3196.

       o  Updated Create-Job, Send-Document, and Send-URI to RECOMMENDED.

       o  Incorporated 'collection' attribute content from RFC 3382.

       o  Obsoleted all attributes and values defined in RFC 3381, as they
          do not interact well with the "finishings" attribute and have
          never been widely implemented.

       o  Deprecated the Purge-Jobs and Restart-Job operations, which
          destroy accounting information.

    Sweet & McDonald             Standards Track                  [Page 187]

    RFC 8011              IPP/1.1: Model and Semantics          January 2017

       o  Dropped type3 registration procedures.

       o  Changed the vendor attribute and keyword naming recommendations to
          use SMI Private Enterprise Numbers ("smiNNN-foo") instead of
          domain names.

       o  Split READ-ONLY Job Description and Printer Description attributes
          into Job Status and Printer Status attributes to match the current
          IANA IPP registry organization.

       o  Referenced all IETF and PWG IPP standards.

       o  Updated OPTIONAL operations, attributes, and values to RECOMMENDED
          for consistency with IPP 2.0, IPP Everywhere, and the IPP
          Implementor's Guide v2.0.

       o  Removed the appendix on media names.  Readers are directed to
          "PWG Media Standardized Names 2.0 (MSN2)" [PWG5101.1].

    11.  References

    11.1.  Normative References

       [ASME-Y14.1M]
                  ASME Y14.1M-2012, "Metric Drawing Sheet Size and Format",
                  March 2013.

       [ISO10175] ISO/IEC 10175, "Information technology -- Text and office
                  systems -- Document Printing Application (DPA) -- Part 1:
                  Abstract service definition and procedures",
                  September 1996.

       [ISO10646] ISO/IEC 10646:2014, JTC1/SC2, "Information technology --
                  Universal Coded Character Set (UCS)", September 2014.

       [ISO8859-1]
                  ISO/IEC 8859-1:1998, "Information technology -- 8-bit
                  single-byte coded graphic character sets -- Part 1: Latin
                  alphabet No. 1", April 1998.

       [PWG5100.1]
                  Sweet, M., "IPP Finishings 2.0 (FIN)", December 2014,
                  <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippfinishings20-20141219-5100.1.pdf>.

    Sweet & McDonald             Standards Track                  [Page 188]

    RFC 8011              IPP/1.1: Model and Semantics          January 2017

       [PWG5100.11]
                  Hastings, T. and D. Fullman, "Internet Printing Protocol
                  (IPP): Job and Printer Extensions -- Set 2 (JPS2)",
                  October 2010, <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippjobprinterext10-20101030-5100.11.pdf>.

       [PWG5100.12]
                  Sweet, M. and I. McDonald, "IPP Version 2.0, 2.1, and
                  2.2", October 2015, <http://ftp.pwg.org/pub/pwg/standards/
                  std-ipp20-20151030-5100.12.pdf>.

       [PWG5100.13]
                  Sweet, M., McDonald, I., and P. Zehler, "IPP: Job and
                  Printer Extensions -- Set 3 (JPS3)", July 2012,
                  <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippjobprinterext3v10-20120727-5100.13.pdf>.

       [PWG5100.14]
                  Sweet, M., McDonald, I., Mitchell, A., and J. Hutchings,
                  "IPP Everywhere", January 2013,
                  <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippeve10-20130128-5100.14.pdf>.

       [PWG5100.15]
                  Sweet, M., "IPP FaxOut Service", June 2014,
                  <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippfaxout10-20140618-5100.15.pdf>.

       [PWG5100.16]
                  Sweet, M., "IPP Transaction-Based Printing Extensions",
                  November 2013, <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ipptrans10-20131108-5100.16.pdf>.

       [PWG5100.17]
                  Zehler, P. and M. Sweet, "IPP Scan Service (SCAN)",
                  September 2014, <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippscan10-20140918-5100.17.pdf>.

       [PWG5100.18]
                  Sweet, M. and I. McDonald, "IPP Shared Infrastructure
                  Extensions (INFRA)", June 2015,
                  <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippinfra10-20150619-5100.18.pdf>.

       [PWG5100.19]
                  Kennedy, S., "IPP Implementor's Guide v2.0 (IG)",
                  August 2015, <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippig20-20150821-5100.19.pdf>.

    Sweet & McDonald             Standards Track                  [Page 189]

    RFC 8011              IPP/1.1: Model and Semantics          January 2017

       [PWG5100.2]
                  Hastings, T. and R. Bergman, "Internet Printing Protocol
                  (IPP): "output-bin" attribute extension", February 2001,
                  <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippoutputbin10-20010207-5100.2.pdf>.

       [PWG5100.3]
                  Ocke, K. and T. Hastings, "Internet Printing Protocol
                  (IPP): Production Printing Attributes -- Set1",
                  February 2001, <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippprodprint10-20010212-5100.3.pdf>.

       [PWG5100.5]
                  Carney, D., Hastings, T., and P. Zehler, "Standard for The
                  Internet Printing Protocol (IPP): Document Object",
                  October 2003, <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippdocobject10-20031031-5100.5.pdf>.

       [PWG5100.6]
                  Zehler, P., Herriot, R., and K. Ocke, "Standard for The
                  Internet Printing Protocol (IPP): Page Overrides",
                  October 2003, <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ipppageoverride10-20031031-5100.6.pdf>.

       [PWG5100.7]
                  Hastings, T. and P. Zehler, "Standard for The Internet
                  Printing Protocol (IPP): Job Extensions", October 2003,
                  <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippjobext10-20031031-5100.7.pdf>.

       [PWG5100.8]
                  Carney, D. and H. Lewis, "Standard for Internet Printing
                  Protocol (IPP): "-actual" attributes", March 2003,
                  <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippactuals10-20030313-5100.8.pdf>.

       [PWG5100.9]
                  McDonald, I. and C. Whittle, "Internet Printing Protocol
                  (IPP): Printer State Extensions v1.0", July 2009,
                  <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-ippstate10-20090731-5100.9.pdf>.

       [PWG5101.1]
                  Sweet, M., Bergman, R., and T. Hastings, "PWG Media
                  Standardized Names 2.0 (MSN2)", March 2013,
                  <http://ftp.pwg.org/pub/pwg/candidates/
                  cs-pwgmsn20-20130328-5101.1.pdf>.

    Sweet & McDonald             Standards Track                  [Page 190]

    RFC 8011              IPP/1.1: Model and Semantics          January 2017

       [RFC20]    Cerf, V., "ASCII format for network interchange", STD 80,
                  RFC 20, DOI 10.17487/RFC0020, October 1969,
                  <http://www.rfc-editor.org/info/rfc20>.

       [RFC793]   Postel, J., "Transmission Control Protocol", STD 7,
                  RFC 793, DOI 10.17487/RFC0793, September 1981,
                  <http://www.rfc-editor.org/info/rfc793>.

       [RFC1035]  Mockapetris, P., "Domain names - implementation and
                  specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
                  November 1987, <http://www.rfc-editor.org/info/rfc1035>.

       [RFC1951]  Deutsch, P., "DEFLATE Compressed Data Format Specification
                  version 1.3", RFC 1951, DOI 10.17487/RFC1951, May 1996,
                  <http://www.rfc-editor.org/info/rfc1951>.

       [RFC1952]  Deutsch, P., "GZIP file format specification version 4.3",
                  RFC 1952, DOI 10.17487/RFC1952, May 1996,
                  <http://www.rfc-editor.org/info/rfc1952>.

       [RFC1977]  Schryver, V., "PPP BSD Compression Protocol", RFC 1977,
                  DOI 10.17487/RFC1977, August 1996,
                  <http://www.rfc-editor.org/info/rfc1977>.

       [RFC2046]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
                  Extensions (MIME) Part Two: Media Types", RFC 2046,
                  DOI 10.17487/RFC2046, November 1996,
                  <http://www.rfc-editor.org/info/rfc2046>.

       [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
                  Requirement Levels", BCP 14, RFC 2119,
                  DOI 10.17487/RFC2119, March 1997,
                  <http://www.rfc-editor.org/info/rfc2119>.

       [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818,
                  DOI 10.17487/RFC2818, May 2000,
                  <http://www.rfc-editor.org/info/rfc2818>.

       [RFC3196]  Hastings, T., Manros, C., Zehler, P., Kugler, C., and H.
                  Holst, "Internet Printing Protocol/1.1: Implementor's
                  Guide", RFC 3196, DOI 10.17487/RFC3196, November 2001,
                  <http://www.rfc-editor.org/info/rfc3196>.

       [RFC3380]  Hastings, T., Herriot, R., Kugler, C., and H. Lewis,
                  "Internet Printing Protocol (IPP): Job and Printer Set
                  Operations", RFC 3380, DOI 10.17487/RFC3380,
                  September 2002, <http://www.rfc-editor.org/info/rfc3380>.

    Sweet & McDonald             Standards Track                  [Page 191]

    RFC 8011              IPP/1.1: Model and Semantics          January 2017

       [RFC3510]  Herriot, R. and I. McDonald, "Internet Printing
                  Protocol/1.1: IPP URL Scheme", RFC 3510,
                  DOI 10.17487/RFC3510, April 2003,
                  <http://www.rfc-editor.org/info/rfc3510>.

       [RFC3629]  Yergeau, F., "UTF-8, a transformation format of
                  ISO 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629,
                  November 2003, <http://www.rfc-editor.org/info/rfc3629>.

       [RFC3805]  Bergman, R., Lewis, H., and I. McDonald, "Printer MIB v2",
                  RFC 3805, DOI 10.17487/RFC3805, June 2004,
                  <http://www.rfc-editor.org/info/rfc3805>.

       [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
                  Resource Identifier (URI): Generic Syntax", STD 66,
                  RFC 3986, DOI 10.17487/RFC3986, January 2005,
                  <http://www.rfc-editor.org/info/rfc3986>.

       [RFC3995]  Herriot, R. and T. Hastings, "Internet Printing Protocol
                  (IPP): Event Notifications and Subscriptions", RFC 3995,
                  DOI 10.17487/RFC3995, March 2005,
                  <http://www.rfc-editor.org/info/rfc3995>.

       [RFC3996]  Herriot, R., Hastings, T., and H. Lewis, "Internet
                  Printing Protocol (IPP): The 'ippget' Delivery Method for
                  Event Notifications", RFC 3996, DOI 10.17487/RFC3996,
                  March 2005, <http://www.rfc-editor.org/info/rfc3996>.

       [RFC3998]  Kugler, C., Lewis, H., and T. Hastings, Ed., "Internet
                  Printing Protocol (IPP): Job and Printer Administrative
                  Operations", RFC 3998, DOI 10.17487/RFC3998, March 2005,
                  <http://www.rfc-editor.org/info/rfc3998>.

       [RFC5051]  Crispin, M., "i;unicode-casemap - Simple Unicode Collation
                  Algorithm", RFC 5051, DOI 10.17487/RFC5051, October 2007,
                  <http://www.rfc-editor.org/info/rfc5051>.

       [RFC5234]  Crocker, D., Ed., and P. Overell, "Augmented BNF for
                  Syntax Specifications: ABNF", STD 68, RFC 5234,
                  DOI 10.17487/RFC5234, January 2008,
                  <http://www.rfc-editor.org/info/rfc5234>.

       [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
                  (TLS) Protocol Version 1.2", RFC 5246,
                  DOI 10.17487/RFC5246, August 2008,
                  <http://www.rfc-editor.org/info/rfc5246>.

    Sweet & McDonald             Standards Track                  [Page 192]

    RFC 8011              IPP/1.1: Model and Semantics          January 2017

       [RFC5646]  Phillips, A., Ed., and M. Davis, Ed., "Tags for
                  Identifying Languages", BCP 47, RFC 5646,
                  DOI 10.17487/RFC5646, September 2009,
                  <http://www.rfc-editor.org/info/rfc5646>.

       [RFC6838]  Freed, N., Klensin, J., and T. Hansen, "Media Type
                  Specifications and Registration Procedures", BCP 13,
                  RFC 6838, DOI 10.17487/RFC6838, January 2013,
                  <http://www.rfc-editor.org/info/rfc6838>.

       [RFC7230]  Fielding, R., Ed., and J. Reschke, Ed., "Hypertext
                  Transfer Protocol (HTTP/1.1): Message Syntax and Routing",
                  RFC 7230, DOI 10.17487/RFC7230, June 2014,
                  <http://www.rfc-editor.org/info/rfc7230>.

       [RFC7472]  McDonald, I. and M. Sweet, "Internet Printing Protocol
                  (IPP) over HTTPS Transport Binding and the 'ipps' URI
                  Scheme", RFC 7472, DOI 10.17487/RFC7472, March 2015,
                  <http://www.rfc-editor.org/info/rfc7472>.

       [RFC7612]  Fleming, P. and I. McDonald, "Lightweight Directory Access
                  Protocol (LDAP): Schema for Printer Services", RFC 7612,
                  DOI 10.17487/RFC7612, June 2015,
                  <http://www.rfc-editor.org/info/rfc7612>.

       [RFC7616]  Shekh-Yusef, R., Ed., Ahrens, D., and S. Bremer, "HTTP
                  Digest Access Authentication", RFC 7616,
                  DOI 10.17487/RFC7616, September 2015,
                  <http://www.rfc-editor.org/info/rfc7616>.

       [RFC7617]  Reschke, J., "The 'Basic' HTTP Authentication Scheme",
                  RFC 7617, DOI 10.17487/RFC7617, September 2015,
                  <http://www.rfc-editor.org/info/rfc7617>.

       [RFC8010]  Sweet, M. and I. McDonald, "Internet Printing
                  Protocol/1.1: Encoding and Transport", RFC 8010,
                  DOI 10.17487/RFC8010, January 2017,
                  <http://www.rfc-editor.org/info/rfc8010>.

    Sweet & McDonald             Standards Track                  [Page 193]

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    11.2.  Informative References

       [HTPP]     Barnett, J., Carter, K., and R. deBry, "Internet Print
                  Protocol Proposal: HTPP -- Hypertext Print Protocol
                  (HTPP/1.0 Initial Draft)", October 1996,
                  <ftp://ftp.pwg.org/pub/pwg/ipp/historic/htpp/
                  overview.ps.gz>.

       [IANA-CS]  IANA, "Registry of Coded Character Sets",
                  <http://www.iana.org/assignments/character-sets/>.

       [IANA-MT]  IANA, "Media Types",
                  <http://www.iana.org/assignments/media-types/>.

       [IANA-PEN]
                  IANA, "Private Enterprise Numbers",
                  <http://www.iana.org/assignments/enterprise-numbers/>.

       [ISO32000] "Document management -- Portable document format --
                  Part 1: PDF 1.7", July 2008, <http://www.adobe.com/
                  devnet/acrobat/pdfs/PDF32000_2008.pdf>.

       [LDPA]     Isaacson, S., Taylor, D., MacKay, M., Zehler, P.,
                  Hastings, T., and C. Manros, "LDPA - Lightweight Document
                  Printing Application", Proposed Internet-Draft,
                  October 1996, <ftp://ftp.pwg.org/pub/pwg/ipp/
                  historic/ldpa/ldpa8.pdf.gz>.

       [P1387.4]  Kirk, M., "POSIX Systems Administration - Part 4: Printing
                  Interfaces, POSIX 1387.4 D8", 1998.

       [PSIS]     Herriot, R., Ed., "X/Open: A Printing System
                  Interoperability Specification (PSIS)", August 1995.

       [PWG-IPP-WG]
                  IEEE-ISTO Printer Working Group, "Internet Printing
                  Protocol Workgroup", <http://www.pwg.org/ipp>.

       [RFC959]   Postel, J. and J. Reynolds, "File Transfer Protocol",
                  STD 9, RFC 959, DOI 10.17487/RFC0959, October 1985,
                  <http://www.rfc-editor.org/info/rfc959>.

       [RFC1179]  McLaughlin, L., "Line printer daemon protocol", RFC 1179,
                  DOI 10.17487/RFC1179, August 1990,
                  <http://www.rfc-editor.org/info/rfc1179>.

    Sweet & McDonald             Standards Track                  [Page 194]

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       [RFC1738]  Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform
                  Resource Locators (URL)", RFC 1738, DOI 10.17487/RFC1738,
                  December 1994, <http://www.rfc-editor.org/info/rfc1738>.

       [RFC2565]  Herriot, R., Ed., Butler, S., Moore, P., and R. Turner,
                  "Internet Printing Protocol/1.0: Encoding and Transport",
                  RFC 2565, DOI 10.17487/RFC2565, April 1999,
                  <http://www.rfc-editor.org/info/rfc2565>.

       [RFC2566]  deBry, R., Hastings, T., Herriot, R., Isaacson, S., and P.
                  Powell, "Internet Printing Protocol/1.0: Model and
                  Semantics", RFC 2566, DOI 10.17487/RFC2566, April 1999,
                  <http://www.rfc-editor.org/info/rfc2566>.

       [RFC2567]  Wright, F., "Design Goals for an Internet Printing
                  Protocol", RFC 2567, DOI 10.17487/RFC2567, April 1999,
                  <http://www.rfc-editor.org/info/rfc2567>.

       [RFC2568]  Zilles, S., "Rationale for the Structure of the Model and
                  Protocol for the Internet Printing Protocol", RFC 2568,
                  DOI 10.17487/RFC2568, April 1999,
                  <http://www.rfc-editor.org/info/rfc2568>.

       [RFC2569]  Herriot, R., Ed., Hastings, T., Jacobs, N., and J. Martin,
                  "Mapping between LPD and IPP Protocols", RFC 2569,
                  DOI 10.17487/RFC2569, April 1999,
                  <http://www.rfc-editor.org/info/rfc2569>.

       [RFC2579]  McCloghrie, K., Ed., Perkins, D., Ed., and J.
                  Schoenwaelder, Ed., "Textual Conventions for SMIv2",
                  STD 58, RFC 2579, DOI 10.17487/RFC2579, April 1999,
                  <http://www.rfc-editor.org/info/rfc2579>.

       [RFC2978]  Freed, N. and J. Postel, "IANA Charset Registration
                  Procedures", BCP 19, RFC 2978, DOI 10.17487/RFC2978,
                  October 2000, <http://www.rfc-editor.org/info/rfc2978>.

       [RFC3239]  Kugler, C., Lewis, H., and T. Hastings, "Internet Printing
                  Protocol (IPP): Requirements for Job, Printer, and Device
                  Administrative Operations", RFC 3239,
                  DOI 10.17487/RFC3239, February 2002,
                  <http://www.rfc-editor.org/info/rfc3239>.

       [RFC3997]  Hastings, T., Ed., deBry, R., and H. Lewis, "Internet
                  Printing Protocol (IPP): Requirements for IPP
                  Notifications", RFC 3997, DOI 10.17487/RFC3997,
                  March 2005, <http://www.rfc-editor.org/info/rfc3997>.

    Sweet & McDonald             Standards Track                  [Page 195]

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       [RFC4122]  Leach, P., Mealling, M., and R. Salz, "A Universally
                  Unique IDentifier (UUID) URN Namespace", RFC 4122,
                  DOI 10.17487/RFC4122, July 2005,
                  <http://www.rfc-editor.org/info/rfc4122>.

       [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
                  IANA Considerations Section in RFCs", BCP 26, RFC 5226,
                  DOI 10.17487/RFC5226, May 2008,
                  <http://www.rfc-editor.org/info/rfc5226>.

       [RFC6068]  Duerst, M., Masinter, L., and J. Zawinski, "The 'mailto'
                  URI Scheme", RFC 6068, DOI 10.17487/RFC6068, October 2010,
                  <http://www.rfc-editor.org/info/rfc6068>.

       [RFC7525]  Sheffer, Y., Holz, R., and P. Saint-Andre,
                  "Recommendations for Secure Use of Transport Layer
                  Security (TLS) and Datagram Transport Layer Security
                  (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525,
                  May 2015, <http://www.rfc-editor.org/info/rfc7525>.

       [SWP]      Moore, P. and S. Butler, "Simple Web Printing (SWP/1.0)",
                  May 1997, <ftp://ftp.pwg.org/pub/pwg/ipp/new_PRO/
                  swp9705.pdf>.

    Sweet & McDonald             Standards Track                  [Page 196]

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    Appendix A.  Formats for IPP Registration Proposals

       In order to propose an IPP extension for registration, the proposer
       must submit an application to IANA by email to "iana@iana.org" or by
       filling out the appropriate form on the IANA web pages
       (http://www.iana.org).  This section specifies the required
       information and the formats for proposing registrations of extensions
       to IPP as provided in Section 7 for:

       1.  attributes

       2.  type2 'keyword' attribute values

       3.  type2 'enum' attribute values

       4.  operations

       5.  status-code values

    A.1.  Attribute Registration

       Type of registration: attribute

       Proposed keyword name of this attribute:

       Types of attributes (Document Description, Document Status, Document
       Template, Event Notifications, Job Description, Job Status, Job
       Template, Operation, Printer Description, Printer Status,
       Subscription Description, Subscription Status, Subscription
       Template):

       Operations to be used if the attribute is an operation attribute:

       Object (Document, Job, Printer, Subscription, etc. if bound to an
       object):

       Attribute syntax(es) (include '1setOf' and range; see Section 5.2):

       If attribute syntax is 'keyword' or 'enum', is it type1 or type2?

       If this is a Printer attribute, MAY the value returned depend on
       "document-format"?  (See Section 7.2.)

       If this is a Job Template attribute, how does its specification
       depend on the value of the "multiple-document-handling" attribute?

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       Specification of this attribute (follow the style of Section 5.2):

       Name of proposer:

       Email address of proposer:

       Note: For attributes, the IPP Designated Expert will be the point of
       contact and change controller for the approved registration
       specification, if any maintenance of the registration specification
       is needed.

    A.2.  type2 'keyword' Attribute Value Registration

       Type of registration: type2 keyword attribute value

       Name of attribute to which this keyword specification is to be added:

       Proposed keyword name of this 'keyword' value:

       Specification of this 'keyword' value (follow the style of
       Section 5.1.4):

       Name of proposer:

       Email address of proposer:

       Note: For type2 keywords, the Designated Expert will be the point of
       contact and change controller for the approved registration
       specification, if any maintenance of the registration specification
       is needed.

    A.3.  type2 'enum' Attribute Value Registration

       Type of registration: type2 enum attribute value

       Name of attribute to which this enum specification is to be added:

       Keyword symbolic name of this enum value:

       Numeric value (to be assigned by the IPP Designated Expert in
       consultation with IANA):

       Specification of this enum value (follow the style of Section 5.1.5):

       Name of proposer:

       Email address of proposer:

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       Note: For type2 enums, the Designated Expert will be the point of
       contact and change controller for the approved registration
       specification, if any maintenance of the registration specification
       is needed.

    A.4.  Operation Registration

       Type of registration: operation

       Proposed name of this operation:

       Numeric "operation-id" value according to Section 5.4.15 (to be
       assigned by the IPP Designated Expert in consultation with IANA):

       Object Target (Document, Job, Printer, Subscription, etc. that
       operation is upon):

       Specification of this operation (follow the style of Section 4):

       Name of proposer:

       Email address of proposer:

       Note: For operations, the IPP Designated Expert will be the point of
       contact and change controller for the approved registration
       specification, if any maintenance of the registration specification
       is needed.

    A.5.  Status-Code Registration

       Type of registration: status-code

       Keyword symbolic name of this status-code value:

       Numeric value (to be assigned by the IPP Designated Expert in
       consultation with IANA):

       Operations that this status-code can be used with:

       Specification of this status-code (follow the style of Appendix B):

       Name of proposer:

       Email address of proposer:

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       Note: For status-code values, the Designated Expert will be the point
       of contact and change controller for the approved registration
       specification, if any maintenance of the registration specification
       is needed.

    Appendix B.  Status-Code Values and Suggested Status-Code Messages

       This section defines status-code enum keywords and values that are
       used to provide semantic information on the results of an operation
       request.  Each operation response MUST include a status-code.  The
       response MAY also contain a status message that provides a short
       textual description of the status.  The status-code is intended for
       use by automata, and the status message is intended for the human
       End User.

       The prefix of the status keyword defines the class of response as
       follows:

       "informational" - Request received, continuing process

       "successful" - The action was successfully received, understood, and
       accepted

       "redirection" - Further action is taken in order to complete the
       request

       "client-error" - The request contains bad syntax or cannot be
       fulfilled

       "server-error" - The IPP object failed to fulfill an apparently valid
       request

       As with type2 enums, IPP status-code values are extensible.
       Regardless of whether all status-code values are recognized, IPP
       Clients MUST understand the class of any status-code, as indicated by
       the prefix, and treat any unrecognized response as being equivalent
       to the first status-code of that class, with the exception that an
       unrecognized response MUST NOT be cached.  For example, if an
       unrecognized status-code of 'client-error-xxx-yyy' is received by the
       Client, it can safely assume that there was something wrong with its
       request and treat the response as if it had received a
       'client-error-bad-request' status-code.  The name of the enum is the
       suggested status message for US English.

       See [PWG5100.19] for guidelines on presenting status messages to
       End Users.

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       The status-code values range from 0x0000 to 0x7fff.  The value ranges
       for each status-code class are as follows:

       "successful" - 0x0000 to 0x00ff

       "informational" - 0x0100 to 0x01ff

       "redirection" - 0x0300 to 0x03ff

       "client-error" - 0x0400 to 0x04ff

       "server-error" - 0x0500 to 0x05ff

       The top half (128 values) of each range (0x0n80 to 0x0nff, for n = 0
       to 5) is reserved for vendor use within each status-code class.
       Values 0x0600 to 0x7fff are reserved for future assignment by
       Standards Track documents and MUST NOT be used.

    B.1.  Status-Code Values

       Each status-code is described below.  Appendix B.2 contains a table
       that indicates which status-code values apply to which operations.
       The Implementor's Guides [RFC3196] [PWG5100.19] provide guidance for
       processing IPP attributes for all operations, including status-code
       values.

    B.1.1.  Informational

       This class of status-code values indicates a provisional response and
       is to be used for informational purposes only.

       There are no values defined in this document for this class of
       status-code values.

    B.1.2.  Successful Status-Code Values

       This class of status-code values indicates that the Client's request
       was successfully received, understood, and accepted.

    B.1.2.1.  successful-ok (0x0000)

       The request has succeeded, and no request attributes were substituted
       or ignored.  In the case of a response to a Job Creation request, the
       'successful-ok' status-code indicates that the request was
       successfully received and validated, and that the Job object has been
       created; it does not indicate that the Job has been processed.  The
       transition of the Job object into the 'completed' state is the only
       indicator that the Job has been printed.

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    B.1.2.2.  successful-ok-ignored-or-substituted-attributes (0x0001)

       The request has succeeded, but some supplied (1) attributes were
       ignored or (2) unsupported values were substituted with supported
       values or were ignored in order to perform the operation without
       rejecting it.  Unsupported attributes, attribute syntaxes, or values
       MUST be returned in the Unsupported Attributes group of the response
       for all operations.  There is an exception to this rule for the query
       operations Get-Printer-Attributes, Get-Jobs, and Get-Job-Attributes
       for the "requested-attributes" operation attribute only.  When the
       supplied values of the "requested-attributes" operation attribute are
       requesting attributes that are not supported, the IPP object SHOULD
       return the "requested-attributes" operation attribute in the
       Unsupported Attributes group of the response (with the unsupported
       values only).  See Sections 4.1.7 and 4.2.1.2.

    B.1.2.3.  successful-ok-conflicting-attributes (0x0002)

       The request has succeeded, but some supplied attribute values
       conflicted with the values of other supplied attributes.  Either
       (1) these conflicting values were substituted with (supported) values
       or (2) the attributes were removed in order to process the Job
       without rejecting it.  Attributes or values that conflict with other
       attributes and have been substituted or ignored MUST be returned in
       the Unsupported Attributes group of the response for all operations
       as supplied by the Client.  See Sections 4.1.7 and 4.2.1.2.

    B.1.3.  Redirection Status-Code Values

       This class of status-code values indicates that further action needs
       to be taken to fulfill the request.

       There are no values defined in this document for this class of
       status-code values.

    B.1.4.  Client Error Status-Code Values

       This class of status-code values is intended for cases in which the
       Client seems to have erred.  The IPP object SHOULD return a message
       containing an explanation of the error situation and whether it is a
       temporary or permanent condition.

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    B.1.4.1.  client-error-bad-request (0x0400)

       The request could not be understood by the IPP object due to
       malformed syntax (such as the value of a fixed-length attribute whose
       length does not match the prescribed length for that attribute -- see
       the Implementor's Guides [RFC3196] [PWG5100.19]).  The IPP
       application SHOULD NOT repeat the request without modifications.

    B.1.4.2.  client-error-forbidden (0x0401)

       The IPP object understood the request but is refusing to fulfill it.
       Additional authentication information or authorization credentials
       will not help, and the request SHOULD NOT be repeated.  This
       status-code is commonly used when the IPP object does not wish to
       reveal exactly why the request has been refused or when no other
       response is applicable.

    B.1.4.3.  client-error-not-authenticated (0x0402)

       The request requires user authentication.  The IPP Client can repeat
       the request with suitable authentication information.  If the request
       already included authentication information, then this status-code
       indicates that authorization has been refused for those credentials.
       If this response contains the same challenge as the prior response
       and the user agent has already attempted authentication at least
       once, then the response message can contain relevant diagnostic
       information.  This status-code reveals more information than
       'client-error-forbidden'.

    B.1.4.4.  client-error-not-authorized (0x0403)

       The requester is not authorized to perform the request.  Additional
       authentication information or authorization credentials will not
       help, and the request SHOULD NOT be repeated.  This status-code is
       used when the IPP object wishes to reveal that the authentication
       information is understandable; however, the requester is explicitly
       not authorized to perform the request.  This status-code reveals more
       information than 'client-error-forbidden' and
       'client-error-not-authenticated'.

    B.1.4.5.  client-error-not-possible (0x0404)

       This status-code is used when the request is for something that
       cannot happen.  For example, there might be a request to cancel a Job
       that has already been canceled or aborted by the system.  The IPP
       Client SHOULD NOT repeat the request.

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    B.1.4.6.  client-error-timeout (0x0405)

       The Client did not produce a request within the time that the IPP
       object was prepared to wait.  For example, a Client issued a
       Create-Job operation and then, after a long period of time, issued a
       Send-Document operation; this error status-code was returned in
       response to the Send-Document request (see Section 4.3.1).  The IPP
       object might have been forced to clean up resources that had been
       held for the waiting additional Documents.  The IPP object was forced
       to close the Job, since the Client took too long.  The Client
       SHOULD NOT repeat the request without modifications.

    B.1.4.7.  client-error-not-found (0x0406)

       The IPP object has not found anything matching the request URI.  No
       indication is given of whether the condition is temporary or
       permanent.  For example, a Client with an old reference to a Job
       (a URI) tries to cancel the Job; however, in the meantime the Job
       might have been completed and all record of it at the Printer has
       been deleted.  This status-code, 'client-error-not-found', is
       returned indicating that the referenced Job cannot be found.  This
       error status-code is also used when a Client supplies a URI as a
       reference to the Document data in either a Print-URI or Send-URI
       operation but the Document cannot be found.

       In practice, an IPP application should avoid a "not found" situation
       by first querying and presenting a list of valid Printer URIs and Job
       URIs to the End User.

    B.1.4.8.  client-error-gone (0x0407)

       The requested object is no longer available, and no forwarding
       address is known.  This condition should be considered permanent.
       Clients with link-editing capabilities should delete references to
       the request URI after user approval.  If the IPP object does not know
       or has no facility to determine whether or not the condition is
       permanent, the status-code 'client-error-not-found' should be used
       instead.

       This response is primarily intended to assist the task of maintenance
       by notifying the recipient that the resource is intentionally
       unavailable and that the IPP object Administrator desires that remote
       links to that resource be removed.  It is not necessary to mark all
       permanently unavailable resources as "gone" or to keep the mark for
       any length of time -- that is left to the discretion of the IPP
       object Administrator and/or Printer implementation.

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    B.1.4.9.  client-error-request-entity-too-large (0x0408)

       The IPP object is refusing to process a request because the request
       entity is larger than the IPP object is willing or able to process.
       An IPP Printer returns this status-code when it limits the size of
       Print Jobs and it receives a Print Job that exceeds that limit or
       when the attributes are so many that their encoding causes the
       request entity to exceed IPP object capacity.

    B.1.4.10.  client-error-request-value-too-long (0x0409)

       The IPP object is refusing to service the request because one or more
       of the Client-supplied attributes have a variable-length value that
       is longer than the maximum length specified for that attribute.  The
       IPP object might not have sufficient resources (memory, buffers,
       etc.) to process (even temporarily), interpret, and/or ignore a value
       larger than the maximum length.  Another use of this error code is
       when the IPP object supports the processing of a large value that is
       less than the maximum length, but during the processing of the
       request as a whole, the object can pass the value onto some other
       system component that is not able to accept the large value.  For
       more details, see the Implementor's Guides [RFC3196] [PWG5100.19].

       Note: For attribute values that are URIs, this rare condition is only
       likely to occur when a Client has improperly submitted a request with
       long query information (e.g., an IPP application allows an End User
       to enter an invalid URI), when the Client has descended into a URI
       "black hole" of redirection (e.g., a redirected URI prefix that
       points to a suffix of itself), or when the IPP object is under attack
       by a Client attempting to exploit security holes present in some IPP
       objects using fixed-length buffers for reading or manipulating the
       request URI.

    B.1.4.11.  client-error-document-format-not-supported (0x040a)

       The IPP object is refusing to service the request because the
       Document data is in a format, as specified in the "document-format"
       operation attribute, that is not supported by the Printer.  This
       error is returned independent of the Client-supplied
       "ipp-attribute-fidelity" attribute.  The Printer MUST return this
       status-code, even if there are other Job Template attributes that are
       not supported as well, since this error is a bigger problem than with
       Job Template attributes.  See Sections 4.1.6.1, 4.1.7, and 4.2.1.1.

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    B.1.4.12.  client-error-attributes-or-values-not-supported (0x040b)

       In a Job Creation request, if the Printer does not support one or
       more attributes, attribute syntaxes, or attribute values supplied in
       the request and the Client supplied the "ipp-attribute-fidelity"
       operation attribute with the 'true' value, the Printer MUST return
       this status-code.  The Printer MUST also return in the Unsupported
       Attributes group all the attributes and/or values supplied by the
       Client that are not supported.  See Section 4.1.7.  Examples would be
       if the request indicates 'iso-a4' media but that media type is not
       supported by the Printer, or if the Client supplies a Job Template
       attribute and the attribute itself is not even supported by the
       Printer.  If the "ipp-attribute-fidelity" attribute is 'false', the
       Printer MUST ignore or substitute values for unsupported Job Template
       attributes and values rather than reject the request and return this
       status-code.

       For any operation where a Client requests attributes (such as a
       Get-Jobs, Get-Printer-Attributes, or Get-Job-Attributes operation),
       if the IPP object does not support one or more of the requested
       attributes, the IPP object simply ignores the unsupported requested
       attributes and processes the request as if they had not been
       supplied, rather than returning this status-code.  In this case,
       the IPP object MUST return the
       'successful-ok-ignored-or-substituted-attributes' status-code and
       SHOULD return the unsupported attributes as values of the
       "requested-attributes" operation attribute in the Unsupported
       Attributes group (see Appendix B.1.2.2).

    B.1.4.13.  client-error-uri-scheme-not-supported (0x040c)

       The scheme of the Client-supplied URI in a Print-URI or a Send-URI
       operation is not supported.  See Sections 4.1.6.1 and 4.1.7.

    B.1.4.14.  client-error-charset-not-supported (0x040d)

       For any operation, if the IPP Printer does not support the charset
       supplied by the Client in the "attributes-charset" operation
       attribute, the Printer MUST reject the operation and return this
       status-code, and any 'text' or 'name' attributes using the 'utf-8'
       charset (Section 4.1.4.1).  See Sections 4.1.6.1 and 4.1.7.

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    B.1.4.15.  client-error-conflicting-attributes (0x040e)

       The request is rejected because some attribute values conflicted with
       the values of other attributes that this document does not permit to
       be substituted or ignored.  The Printer MUST also return in the
       Unsupported Attributes group the conflicting attributes supplied by
       the Client.  See Sections 4.1.7 and 4.2.1.2.

    B.1.4.16.  client-error-compression-not-supported (0x040f)

       The IPP object is refusing to service the request because the
       Document data, as specified in the "compression" operation attribute,
       is compressed in a way that is not supported by the Printer.  This
       error is returned independent of the Client-supplied
       "ipp-attribute-fidelity" attribute.  The Printer MUST return this
       status-code, even if there are other Job Template attributes that are
       not supported as well, since this error is a bigger problem than with
       Job Template attributes.  See Sections 4.1.6.1, 4.1.7, and 4.2.1.1.

    B.1.4.17.  client-error-compression-error (0x0410)

       The IPP object is refusing to service the request because the
       Document data cannot be decompressed when using the algorithm
       specified by the "compression" operation attribute.  This error is
       returned independent of the Client-supplied "ipp-attribute-fidelity"
       attribute.  The Printer MUST return this status-code, even if there
       are Job Template attributes that are not supported as well, since
       this error is a bigger problem than with Job Template attributes.
       See Sections 4.1.7 and 4.2.1.1.

    B.1.4.18.  client-error-document-format-error (0x0411)

       The IPP object is refusing to service the request because the Printer
       encountered an error in the Document data while interpreting it.
       This error is returned independent of the Client-supplied
       "ipp-attribute-fidelity" attribute.  The Printer MUST return this
       status-code, even if there are Job Template attributes that are not
       supported as well, since this error is a bigger problem than with Job
       Template attributes.  See Sections 4.1.7 and 4.2.1.1.

    B.1.4.19.  client-error-document-access-error (0x0412)

       The IPP object is refusing to service the Print-URI or Send-URI
       request because the Printer encountered an access error while
       attempting to validate the accessibility of, or access to, the
       Document data specified in the "document-uri" operation attribute.
       The Printer MAY also return a specific Document access error code
       using the "document-access-error" operation attribute (see

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       Section 4.1.6.4).  This error is returned independent of the
       Client-supplied "ipp-attribute-fidelity" attribute.  The Printer MUST
       return this status-code, even if there are Job Template attributes
       that are not supported as well, since this error is a bigger problem
       than with Job Template attributes.  See Sections 4.1.6.1 and 4.1.7.

    B.1.5.  Server Error Status-Code Values

       This class of status-code values indicates cases in which the IPP
       object is aware that it has erred or is incapable of performing the
       request.  The IPP object SHOULD include a message containing an
       explanation of the error situation, and whether it is a temporary or
       permanent condition.

    B.1.5.1.  server-error-internal-error (0x0500)

       The IPP object encountered an unexpected condition that prevented it
       from fulfilling the request.  This error status-code differs from
       'server-error-temporary-error' in that it implies a more permanent
       type of internal error.  It also differs from
       'server-error-device-error' in that it implies an unexpected
       condition (unlike a paper-jam or out-of-toner problem, which is
       undesirable but expected).  This error status-code indicates that
       intervention by a knowledgeable human is probably required.

    B.1.5.2.  server-error-operation-not-supported (0x0501)

       The IPP object does not support the functionality required to fulfill
       the request.  This is the appropriate response when the IPP object
       does not recognize an operation or is not capable of supporting it.
       See Sections 4.1.6.1 and 4.1.7.

    B.1.5.3.  server-error-service-unavailable (0x0502)

       The IPP object is currently unable to handle the request due to
       temporary overloading or due to maintenance of the IPP object.  The
       implication is that this is a temporary condition that will be
       alleviated after some delay.  If known, the length of the delay can
       be indicated in the message.  If no delay is given, the IPP
       application should handle the response as it would for a
       'server-error-temporary-error' response.  If the condition is more
       permanent, the 'client-error-gone' or 'client-error-not-found' error
       status-code could be used.

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    B.1.5.4.  server-error-version-not-supported (0x0503)

       The IPP object does not support or refuses to support the IPP version
       that was supplied as the value of the "version-number" operation
       parameter in the request.  The IPP object is indicating that it is
       unable or unwilling to complete the request using the same major and
       minor version number as supplied in the request, other than with this
       error message.  The error response SHOULD contain a "status-message"
       attribute (see Section 4.1.6.2) describing why that version is not
       supported and what other versions are supported by that IPP object.
       See Sections 4.1.6.1, 4.1.7, and 4.1.8.

       The error response MUST identify in the "version-number" operation
       parameter the closest version number that the IPP object does
       support.  For example, if a Client supplies version '1.0' and an
       IPP/1.1 object supports version '1.0', then it responds with
       version '1.0' in all responses to such a request.  If the IPP/1.1
       object does not support version '1.0', then it should accept the
       request and respond with version '1.1' or can reject the request and
       respond with this error code and version '1.1'.  If a Client supplies
       version '1.2', the IPP/1.1 object should accept the request and
       return version '1.1' or can reject the request and respond with this
       error code and version '1.1'.  See Sections 4.1.8 and 5.3.14.

    B.1.5.5.  server-error-device-error (0x0504)

       A Printer error, such as a paper jam, occurs while the IPP object
       processes a Print or send operation.  The response contains the true
       Job status (the values of the "job-state" and "job-state-reasons"
       attributes).  Additional information can be returned in the OPTIONAL
       "job-state-message" attribute value or in the OPTIONAL status message
       that describes the error in more detail.  This error status-code is
       only returned in situations where the Printer is unable to accept the
       Job Creation request because of such a device error.  For example, if
       the Printer is unable to spool and can only accept one Job at a time,
       the reason it might reject a Job Creation request is that the Printer
       currently has a paper jam.  In many cases, however, where the Printer
       can accept the request even though the Printer has some error
       condition, the 'successful-ok' status-code will be returned.  In such
       a case, the Client would look at the returned Job object attributes
       or later query the Printer to determine its state and state reasons.

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    B.1.5.6.  server-error-temporary-error (0x0505)

       A temporary error such as a buffer-full write error, a memory
       overflow (i.e., the Document data exceeds the memory of the Printer),
       or a disk-full condition, occurs while the IPP Printer processes an
       operation.  The Client MAY try the unmodified request again at some
       later point in time with an expectation that the temporary internal
       error condition has been cleared.  Alternatively, as an
       implementation option, a Printer MAY delay the response until the
       temporary condition is cleared so that no error is returned.

    B.1.5.7.  server-error-not-accepting-jobs (0x0506)

       This is a temporary error indicating that the Printer is not
       currently accepting Jobs because the Administrator has set the value
       of the Printer's "printer-is-accepting-jobs" attribute to 'false' (by
       means outside the scope of this IPP/1.1 document).

    B.1.5.8.  server-error-busy (0x0507)

       This is a temporary error indicating that the Printer is too busy
       processing Jobs and/or other requests.  The Client SHOULD try the
       unmodified request again at some later point in time with an
       expectation that the temporary busy condition will have been cleared.

    B.1.5.9.  server-error-job-canceled (0x0508)

       This is an error indicating that the Job has been canceled by an
       Operator or the system while the Client was transmitting the data to
       the IPP Printer.  If a "job-id" attribute and a "job-uri" attribute
       had been created, then they are returned in the Print-Job,
       Send-Document, or Send-URI response as usual; otherwise, no "job-id"
       and "job-uri" attributes are returned in the response.

    B.1.5.10.  server-error-multiple-document-jobs-not-supported (0x0509)

       The IPP object does not support multiple Documents per Job, and a
       Client attempted to supply Document data with a second Send-Document
       or Send-URI operation.

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    B.2.  Status-Code Values for IPP Operations

       PJ = Print-Job, PU = Print-URI, CJ = Create-Job, SD = Send-Document,
       SU = Send-URI, V = Validate-Job, GA = Get-Job-Attributes and
       Get-Printer-Attributes, GJ = Get-Jobs, C = Cancel-Job

                                                      IPP Operations
       IPP Status Keyword                       PJ PU CJ SD SU V GA GJ C
       ------------------                       -- -- -- -- -- - -- -- -
       successful-ok                            x  x  x  x  x  x x  x  x
       successful-ok-ignored-or-substituted-    x  x  x  x  x  x x  x  x
            attributes
       successful-ok-conflicting-attributes     x  x  x  x  x  x x  x  x
       client-error-bad-request                 x  x  x  x  x  x x  x  x
       client-error-forbidden                   x  x  x  x  x  x x  x  x
       client-error-not-authenticated           x  x  x  x  x  x x  x  x
       client-error-not-authorized              x  x  x  x  x  x x  x  x
       client-error-not-possible                x  x  x  x  x  x x  x  x
       client-error-timeout                              x  x
       client-error-not-found                   x  x  x  x  x  x x  x  x
       client-error-gone                        x  x  x  x  x  x x  x  x
       client-error-request-entity-too-large    x  x  x  x  x  x x  x  x
       client-error-request-value-too-long      x  x  x  x  x  x x  x  x
       client-error-document-format-not-        x  x     x  x  x x
            supported
       client-error-attributes-or-values-not-   x  x  x  x  x  x x  x  x
            supported
       client-error-uri-scheme-not-supported       x        x
       client-error-charset-not-supported       x  x  x  x  x  x x  x  x
       client-error-conflicting-attributes      x  x  x  x  x  x x  x  x
       client-error-compression-not-supported   x  x     x  x  x
       client-error-compression-error           x  x     x  x
       client-error-document-format-error       x  x     x  x
       client-error-document-access-error          x        x
       server-error-internal-error              x  x  x  x  x  x x  x  x
       server-error-operation-not-supported        x  x  x  x
       server-error-service-unavailable         x  x  x  x  x  x x  x  x
       server-error-version-not-supported       x  x  x  x  x  x x  x  x
       server-error-device-error                x  x  x  x  x
       server-error-temporary-error             x  x  x  x  x
       server-error-not-accepting-jobs          x  x  x        x
       server-error-busy                        x  x  x  x  x  x x  x  x
       server-error-job-canceled                x        x  x
       server-error-multiple-document-jobs-              x  x
              not-supported

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       HJ = Hold-Job, RJ = Release-Job, RS = Restart-Job,
       PP = Pause-Printer, RP = Resume-Printer, PJ = Purge-Jobs

                                                IPP Operations (cont.)
       IPP Status Keyword                       HJ RJ RS PP RP PJ
       ------------------                       -- -- -- -- -- --
       successful-ok                            x  x  x  x  x  x
       successful-ok-ignored-or-substituted-    x  x  x  x  x  x
            attributes
       successful-ok-conflicting-attributes     x  x  x  x  x  x
       client-error-bad-request                 x  x  x  x  x  x
       client-error-forbidden                   x  x  x  x  x  x
       client-error-not-authenticated           x  x  x  x  x  x
       client-error-not-authorized              x  x  x  x  x  x
       client-error-not-possible                x  x  x  x  x  x
       client-error-timeout
       client-error-not-found                   x  x  x  x  x  x
       client-error-gone                        x  x  x  x  x  x
       client-error-request-entity-too-large    x  x  x  x  x  x
       client-error-request-value-too-long      x  x  x  x  x  x
       client-error-document-format-not-
            supported
       client-error-attributes-or-values-not-   x  x  x  x  x  x
            supported
       client-error-uri-scheme-not-supported
       client-error-charset-not-supported       x  x  x  x  x  x
       client-error-conflicting-attributes      x  x  x  x  x  x
       client-error-compression-not-supported
       client-error-compression-error
       client-error-document-format-error
       client-error-document-access-error
       server-error-internal-error              x  x  x  x  x  x
       server-error-operation-not-supported     x  x  x  x  x  x
       server-error-service-unavailable         x  x  x  x  x  x
       server-error-version-not-supported       x  x  x  x  x  x
       server-error-device-error
       server-error-temporary-error             x  x  x  x  x  x
       server-error-not-accepting-jobs
       server-error-busy                        x  x  x  x  x  x
       server-error-job-canceled
       server-error-multiple-document-jobs-
              not-supported

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    Appendix C.  Processing IPP Attributes

       When submitting a Print Job to a Printer, the IPP Model allows a
       Client to supply operation and Job Template attributes along with the
       Document data.  These Job Template attributes in the Job Creation
       request affect the rendering, production, and finishing of the
       Documents in the Job.  Similar types of instructions can also be
       contained in the Document data itself.  In addition, the Printer has
       a set of attributes that describe what rendering and finishing
       processes are supported by that Printer.  This model, which allows
       for flexibility and power, also introduces the potential that
       Client-supplied attributes can conflict with either:

       o  what the implementation is capable of realizing (i.e., what the
          Printer supports), or

       o  the instructions embedded within the Document data itself.

       The following sections describe how these two types of conflicts are
       handled in the IPP Model.

    C.1.  Fidelity

       If there is a conflict between what the Client requests and what a
       Printer supports, the Client can request one of two possible
       conflict-handling mechanisms:

       1)  either reject the Job, since the Job cannot be processed exactly
           as specified, or

       2)  allow the Printer to make any changes necessary to proceed with
           processing the Job the best it can.

       In the first case, the Client is indicating the following to the
       Printer: "Print the Job exactly as specified with no exceptions, and
       if that can't be done, don't even bother printing the Job at all."
       In the second case, the Client is indicating the following to the
       Printer: "It is more important to make sure the Job is printed rather
       than be processed exactly as specified; just make sure the Job is
       printed even if some Client-supplied attributes need to be changed or
       ignored."

       The IPP Model accounts for this situation by introducing an
       "ipp-attribute-fidelity" attribute.

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       In a Job Creation request, "ipp-attribute-fidelity" is a boolean
       operation attribute that MAY be supplied by the Client.  The value
       'true' indicates that total fidelity to Client-supplied Job Template
       attributes and values is required.  The Client is requesting that the
       Job be printed exactly as specified, and if that is not possible,
       then the Job MUST be rejected rather than processed incorrectly.  The
       value 'false' indicates that a reasonable attempt to print the Job is
       acceptable.  If a Printer does not support some of the
       Client-supplied Job Template attributes or values, the Printer MUST
       ignore or replace them with supported values.  The Printer can choose
       to substitute the default value associated with that attribute or use
       some other supported value that is similar to the unsupported
       requested value.  For example, if a Client supplies a "media" value
       of 'na_letter_8.5x11in', the Printer can choose to substitute
       'iso_a4_210x297mm' rather than a default value of
       'na_personal_3.625x6.5in'.  If the Client does not supply the
       "ipp-attribute-fidelity" attribute, the Printer assumes a value of
       'false'.

       Each Printer implementation MUST support both types of "fidelity"
       printing (that is, whether the Client supplies a value of 'true' or
       'false'):

       o  If the Client supplies 'false' or does not supply the attribute,
          the Printer MUST always accept the request by ignoring unsupported
          Job Template attributes and by substituting unsupported values of
          supported Job Template attributes with supported values.

       o  If the Client supplies 'true', the Printer MUST reject the request
          if the Client supplies unsupported Job Template attributes.

       Since a Client can always query a Printer to find out exactly what is
       and is not supported, "ipp-attribute-fidelity" set to 'false' is
       useful when:

       1)  The End User uses a command line interface to request attributes
           that might not be supported.

       2)  In a GUI context, if the End User expects the Job might be moved
           to another Printer and prefers a suboptimal result to nothing
           at all.

       3)  The End User just wants something reasonable in lieu of nothing
           at all.

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    C.2.  Page Description Language (PDL) Override

       If there is a conflict between the value of an IPP Job Template
       attribute and a corresponding instruction in the Document data, the
       value of the IPP attribute SHOULD take precedence over the Document
       instruction.  Consider the case where a previously formatted file of
       Document data is sent to an IPP Printer.  In this case, if the Client
       supplies any attributes at Job submission time, the Client desires
       that those attributes override the embedded instructions.  Consider
       the case where a previously formatted Document has embedded in it
       commands to load 'iso-a4' media.  However, the Document is passed to
       an End User that only has access to a Printer with 'na-letter' media
       loaded.  That End User most likely wants to submit that Document to
       an IPP Printer with the "media" Job Template attribute set to
       'na-letter'.  Attributes supplied at Job submission time should take
       precedence over the embedded PDL instructions.  However, until
       companies that supply Document data interpreters allow a way for
       external IPP attributes to take precedence over embedded Job
       production instructions, a Printer might not be able to support the
       semantics that IPP attributes override the embedded instructions.

       The IPP Model accounts for this situation by introducing a
       "pdl-override-supported" attribute that describes the Printer's
       capabilities to override instructions embedded in the PDL data
       stream.  The value of the "pdl-override-supported" attribute is
       configured by means outside the scope of this IPP/1.1 document.

       This REQUIRED Printer attribute takes on the following values:

       o  'attempted': This value indicates that the Printer attempts to
          make the IPP attribute values take precedence over embedded
          instructions in the Document data; however, there is no guarantee.

       o  'not-attempted': This value indicates that the Printer makes no
          attempt to make the IPP attribute values take precedence over
          embedded instructions in the Document data.

       At Job processing time, an implementation that supports the value of
       'attempted' might do one of several different actions:

       1)  Generate an Output-Device-specific command sequence to realize
           the feature represented by the IPP attribute value.

       2)  Parse the Document data itself and replace the conflicting
           embedded instruction with a new embedded instruction that matches
           the intent of the IPP attribute value.

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       3)  Indicate to the Printer that external supplied attributes take
           precedence over embedded instructions and then pass the external
           IPP attribute values to the Document data interpreter.

       4)  Anything else that allows for the semantics that IPP attributes
           override embedded Document data instructions.

       Since 'attempted' does not offer any type of guarantee, even though a
       given Printer might not do a very "good" job of attempting to ensure
       that IPP attributes take a higher precedence over instructions
       embedded in the Document data, it would still be a conforming
       implementation.

       At Job processing time, an implementation that supports the value of
       'not-attempted' might do one of the following actions:

       1)  Simply prepend the Document data with the PDL instruction that
           corresponds to the Client-supplied PDL attribute, such that if
           the Document data also has the same PDL instruction it will
           override what the Printer prepended.  In other words, this
           implementation is using the same implementation semantics for the
           Client-supplied IPP attributes as for the Printer defaults.

       2)  Parse the Document data and replace the conflicting embedded
           instruction with a new embedded instruction that approximates,
           but does not match, the semantic intent of the IPP attribute
           value.

       Note: The "ipp-attribute-fidelity" attribute applies to the Printer's
       ability to either accept or reject other unsupported Job Template
       attributes.  In other words, if "ipp-attribute-fidelity" is set to
       'true', a Job is accepted if and only if the Client-supplied Job
       Template attributes and values are supported by the Printer.  Whether
       these attributes actually affect the processing of the Job when the
       Document data contains embedded instructions depends on the ability
       of the Printer to override the instructions embedded in the Document
       data with the semantics of the IPP attributes.  If the Document data
       attributes can be overridden ("pdl-override-supported" set to
       'attempted'), the Printer makes an attempt to use the IPP attributes
       when processing the Job.  If the Document data attributes cannot be
       overridden ("pdl-override-supported" set to 'not-attempted'), the
       Printer makes no attempt to override the embedded Document data
       instructions with the IPP attributes when processing the Job, and
       hence, the IPP attributes can fail to affect the Job processing and
       output when the corresponding instruction is embedded in the
       Document data.

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    C.3.  Using Job Template Attributes during Document Processing

       The Printer uses some of the Job's Job Template attributes during the
       processing of the Document data associated with that Job.  These
       include, but are not limited to, "orientation-requested",
       "number-up", "sides", "media", and "copies".  The processing of each
       Document in a Job object MUST follow the steps below.  These steps
       are intended only to identify when and how attributes are to be used
       in processing Document data; any alternative steps that accomplish
       the same effect can be used to implement this specification document.

       1.  Using the Client-supplied "document-format" attribute or some
           form of Document format detection algorithm (if the value of
           "document-format" is not specific enough), determine whether the
           Document data has already been formatted for printing.  If the
           Document data has been formatted, then go to step 2.  Otherwise,
           the Document data MUST be formatted.  The formatting detection
           algorithm is implementation defined and is not specified by this
           document.  The formatting of the Document data uses the
           "orientation-requested" attribute to determine how the formatted
           print data should be placed on an Input Page; see Section 5.2.10
           for details.

       2.  The Document data is a set of Input Pages in a known media type.
           The "page-ranges" attribute is used to select, as specified in
           Section 5.2.7, a sub-sequence of the pages in the print-stream
           that are to be processed and imaged.

       3.  The input for this step is a sequence of Input Pages.  This step
           is controlled by the "number-up" attribute.  If the value of
           "number-up" is N, then during the processing of the Input Pages
           each N Input Pages are positioned, as specified in Section 5.2.9,
           to create a single Impression.  If a given Document does not have
           N more Input Pages, then the completion of the Impression is
           controlled by the "multiple-document-handling" attribute as
           described in Section 5.2.4; when the value of this attribute is
           'single-document' or 'single-document-new-sheet', the Input Pages
           of Document data from subsequent Documents are used to complete
           the Impression.

       The size (scaling), position (translation), and rotation of the Input
       Pages on the Impression are implementation defined.  Note that during
       this process the Input Pages can be rendered to a form suitable for
       placing on the Impression; this rendering is controlled by the values
       of the "printer-resolution" and "print-quality" attributes as
       described in Sections 5.2.12 and 5.2.13.  In the case where N = 1,
       the Impression is nearly the same as the Input Page; the differences

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       would only be in the size, position, and rotation of the Input Page
       and/or any decoration, such as a frame for the page, that is added by
       the implementation.

       1.  The collection of Impressions is placed, in sequence, onto sides
           of the Media Sheets.  This placement is controlled by the "sides"
           attribute and the orientation of the Input Page, as described in
           Section 5.2.8.  The orientation of the Input Pages affects the
           orientation of the Impression; for example, if "number-up" equals
           2, then, typically, two portrait Input Pages become one landscape
           Impression.  Note that the placement of Impressions onto Media
           Sheets is also controlled by the "multiple-document-handling"
           attribute as described in Section 5.2.4.

       2.  The "copies" and "multiple-document-handling" attributes are used
           to determine how many copies of each Media Sheet are printed and
           in what order.  See Sections 5.2.4 and 5.2.5 for details.

       3.  When the correct number of copies are created, the Media Sheets
           are finished according to the values of the "finishings"
           attribute as described in Section 5.2.6.  Note that sometimes
           finishing processes can require manual intervention to perform
           the finishing processes on the copies, especially uncollated
           copies.  This document allows any or all of the processing steps
           to be performed automatically or manually, at the discretion of
           the Printer.

    Appendix D.  Generic Directory Schema

       This section defines a generic schema for an entry in a directory
       service.  Implementations of this schema are defined by "Lightweight
       Directory Access Protocol (LDAP): Schema for Printer Services"
       [RFC7612] and "IPP Everywhere" [PWG5100.14].  A directory service is
       a means by which service users can locate service providers.  In IPP
       environments, this means that IPP Printers can be registered (either
       automatically or with the help of an Administrator) as entries of
       type Printer in the directory using an implementation-specific
       mechanism such as entry attributes, entry type fields, specific
       branches, etc.  Directory Clients can search or browse for entries of
       type Printer.  Clients use the directory service to find entries
       based on naming, organizational contexts, or filtered searches on
       attribute values of entries.  For example, a Client can find all
       Printers in the "Local Department" context.  Authentication and
       authorization are also often part of a directory service so that an
       Administrator can place limits on End Users so that they are only
       allowed to find entries to which they have certain access rights.
       IPP itself does not require any specific directory service protocol
       or provider.

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       Note: Some directory implementations allow for the notion of
       "aliasing".  That is, one directory entry object can appear as
       multiple directory entry objects with different names for each
       object.  In each case, each alias refers to the same directory entry
       object, which refers to a single IPP Printer.

       The generic schema is a subset of IPP Printer Job Template and
       Printer Description attributes (Sections 5.2 and 5.4).  These
       attributes are identified as either RECOMMENDED or OPTIONAL for the
       directory entry itself.  This conformance labeling is NOT the same
       conformance labeling applied to the attributes of IPP Printer
       objects.  The conformance labeling in this appendix is intended to
       apply to directory templates and to IPP Printer implementations that
       subscribe by adding one or more entries to a directory.  RECOMMENDED
       attributes SHOULD be associated with each directory entry.  OPTIONAL
       attributes MAY be associated with the directory entry (if known or
       supported).  In addition, all directory entry attributes SHOULD
       reflect the current attribute values for the corresponding Printer.

       As much as possible, the names of attributes in directory schema and
       entries SHOULD be the same as the IPP Printer attribute names as
       shown.

       In order to bridge between the directory service and the IPP Printer,
       one of the RECOMMENDED directory entry attributes is the Printer's
       "printer-uri-supported" attribute.  The directory Client queries the
       "printer-uri-supported" attribute (or its equivalent) in the
       directory entry, and then the IPP Client addresses the IPP Printer
       using one of its URIs.  The "uri-security-supported" attribute
       identifies the protocol (if any) used to secure a channel.

       The attributes in Table 23 define the generic schema for directory
       entries of type Printer.

       +------------------------------------+-------------+----------------+
       | Attribute                          | Conformance | Section        |
       +------------------------------------+-------------+----------------+
       | charset-supported                  | OPTIONAL    | Section 5.4.18 |
       +------------------------------------+-------------+----------------+
       | color-supported                    | RECOMMENDED | Section 5.4.26 |
       +------------------------------------+-------------+----------------+
       | compression-supported              | RECOMMENDED | Section 5.4.32 |
       +------------------------------------+-------------+----------------+
       | document-format-supported          | RECOMMENDED | Section 5.4.22 |
       +------------------------------------+-------------+----------------+
       | finishings-supported               | OPTIONAL    | Section 5.2.6  |

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       +------------------------------------+-------------+----------------+
       | generated-natural-language-        | OPTIONAL    | Section 5.4.20 |
       | supported                          |             |                |
       +------------------------------------+-------------+----------------+
       | ipp-versions-supported             | RECOMMENDED | Section 5.4.14 |
       +------------------------------------+-------------+----------------+
       | media-supported                    | RECOMMENDED | Section 5.2.11 |
       +------------------------------------+-------------+----------------+
       | multiple-document-jobs-supported   | OPTIONAL    | Section 5.4.16 |
       +------------------------------------+-------------+----------------+
       | number-up-supported                | OPTIONAL    | Section 5.2.9  |
       +------------------------------------+-------------+----------------+
       | pages-per-minute-color             | OPTIONAL    | Section 5.4.37 |
       +------------------------------------+-------------+----------------+
       | pages-per-minute                   | OPTIONAL    | Section 5.4.36 |
       +------------------------------------+-------------+----------------+
       | print-quality-supported            | OPTIONAL    | Section 5.2.13 |
       +------------------------------------+-------------+----------------+
       | printer-info                       | OPTIONAL    | Section 5.4.6  |
       +------------------------------------+-------------+----------------+
       | printer-location                   | RECOMMENDED | Section 5.4.5  |
       +------------------------------------+-------------+----------------+
       | printer-make-and-model             | RECOMMENDED | Section 5.4.9  |
       +------------------------------------+-------------+----------------+
       | printer-more-info                  | OPTIONAL    | Section 5.4.7  |
       +------------------------------------+-------------+----------------+
       | printer-name                       | RECOMMENDED | Section 5.4.4  |
       +------------------------------------+-------------+----------------+
       | printer-resolution-supported       | OPTIONAL    | Section 5.2.12 |
       +------------------------------------+-------------+----------------+
       | printer-uri-supported              | RECOMMENDED | Section 5.4.1  |
       +------------------------------------+-------------+----------------+
       | sides-supported                    | RECOMMENDED | Section 5.2.8  |
       +------------------------------------+-------------+----------------+
       | uri-authentication-supported       | RECOMMENDED | Section 5.4.2  |
       +------------------------------------+-------------+----------------+
       | uri-security-supported             | RECOMMENDED | Section 5.4.3  |
       +------------------------------------+-------------+----------------+

                     Table 23: Attributes in Directory Entries

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    Acknowledgements

       The authors would like to acknowledge the following individuals for
       their contributions to the original IPP/1.1 specifications:

       Roger deBry, Tom Hastings (original RFC 2911 editor), Robert Herriot,
       Scott A. Isaacson, Kirk Ocke, Patrick Powell, and Peter Zehler

    Authors' Addresses

       Michael Sweet
       Apple Inc.
       1 Infinite Loop
       MS 111-HOMC
       Cupertino, CA  95014
       United States of America

       Email: msweet@apple.com

       Ira McDonald
       High North, Inc.
       PO Box 221
       Grand Marais, MI  49839
       United States of America

       Phone: +1 906-494-2434
       Email: blueroofmusic@gmail.com

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