    Internet Engineering Task Force (IETF)                          D. Kumar
    Request for Comments: 8533                                         Cisco
    Category: Standards Track                                        M. Wang
    ISSN: 2070-1721                                               Q. Wu, Ed.
                                                                      Huawei
                                                                   R. Rahman
                                                                 S. Raghavan
                                                                       Cisco
                                                                  April 2019

         A YANG Data Model for Retrieval Methods for the Management of
          Operations, Administration, and Maintenance (OAM) Protocols
                     That Use Connectionless Communications

    Abstract

       This document presents a retrieval method YANG data model for
       connectionless Operations, Administration, and Maintenance (OAM)
       protocols.  It provides technology-independent RPC operations for OAM
       protocols that use connectionless communication.  The retrieval
       methods model herein presented can be extended to include technology-
       specific details.  There are two key benefits of this approach:
       First, it leads to uniformity between OAM protocols.  Second, it
       supports both nested OAM workflows (i.e., performing OAM functions at
       different or the same levels through a unified interface) as well as
       interactive OAM workflows (i.e., performing OAM functions at the same
       levels through a unified interface).

    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
       https://www.rfc-editor.org/info/rfc8533.

    Kumar, et al.                Standards Track                    [Page 1]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

    Copyright Notice

       Copyright (c) 2019 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
       (https://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.

    Table of Contents

       1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
       2.  Conventions Used in This document . . . . . . . . . . . . . .   3
         2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   4
         2.2.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   4
       3.  Overview of the Connectionless OAM Retrieval Methods Model  .   4
         3.1.  RPC Operation Definitions . . . . . . . . . . . . . . . .   4
         3.2.  OAM Retrieval Methods Hierarchy . . . . . . . . . . . . .   7
       4.  OAM Retrieval Methods YANG Module . . . . . . . . . . . . . .  16
       5.  Security Considerations . . . . . . . . . . . . . . . . . . .  26
       6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  26
       7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  27
         7.1.  Normative References  . . . . . . . . . . . . . . . . . .  27
         7.2.  Informative References  . . . . . . . . . . . . . . . . .  28
       Appendix A.  Extending Connectionless OAM Method Module Example .  29
         A.1.  Example of New Retrieval Procedures Model . . . . . . . .  29
       Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  40
       Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  41

    Kumar, et al.                Standards Track                    [Page 2]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

    1.  Introduction

       Operations, Administration, and Maintenance (OAM) are important
       networking functions that allow operators to:

       1.  monitor network communications (i.e., reachability verification
           and Continuity Check)

       2.  troubleshoot failures (i.e., fault verification and localization)

       3.  monitor service-level agreements and performance (i.e.,
           performance management)

       An overview of OAM tools is presented in [RFC7276].

       Ping and Traceroute [RFC4443], as well as Bidirectional Forwarding
       Detection (BFD) [RFC5880], are well-known fault verification and
       isolation tools, respectively, for IP networks [RFC792].  Over the
       years, different technologies have developed similar toolsets for
       equivalent purposes.

       This document presents an on-demand retrieval method YANG data model
       for OAM protocols that use connectionless communication.  This model
       provides technology-independent RPC operations for OAM protocols that
       use connectionless communication (i.e., connectionless OAM).  It is
       separated from the generic YANG data model for connectionless OAM
       [RFC8532] and can avoid mixing the models for the retrieved data from
       the retrieval procedures.  It is expected that retrieval procedures
       will evolve faster than the data model [RFC8532] and will allow new
       procedures to be defined for retrieval of the same data defined by
       the generic YANG data model for connectionless OAM.

    2.  Conventions Used in This document

       The following terms are defined in [RFC6241] and are used in this
       document:

       o  client

       o  configuration data

       o  server

       o  state data

    Kumar, et al.                Standards Track                    [Page 3]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

       The following terms are defined in [RFC6020] and are used in this
       document:

       o  augment

       o  data model

       o  data node

       The terminology for describing YANG data models is found in
       [RFC6020].

    2.1.  Terminology

       TP - Test Point

       MAC - Media Access Control

       RPC - Remote Procedure Call

       RPC Operation - A specific Remote Procedure Call

    2.2.  Tree Diagrams

       Tree diagrams used in this document follow the notation defined in
       [RFC8340].

    3.  Overview of the Connectionless OAM Retrieval Methods Model

       This document describes an on-demand retrieval method YANG data model
       for OAM protocols that use connectionless communication.  This model
       provides technology-independent retrieval procedures (RPC operations)
       for connectionless OAM protocols.  It provides a flexible way to
       retrieve the data that is defined by the "ietf-connectionless-
       oam.yang" module [RFC8532].

    3.1.  RPC Operation Definitions

       The RPC model facilitates issuing commands to a Network Configuration
       Protocol (NETCONF) server (in this case to the device that needs to
       execute the OAM command) and obtaining a response.

       Under the "connectionless-oam-methods" module, we summarize common
       OAM functions and define two generic RPC operations: 'continuity-
       check' and 'path-discovery'.  In practice, these RPC operations are
       activated on demand and are supported by corresponding technology-
       specific OAM tools [RFC7276].  For example, for the IP OAM model, the
       Continuity Check RPC corresponds to the IP Ping [RFC792] [RFC4443],

    Kumar, et al.                Standards Track                    [Page 4]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

       while the path discovery RPC operation corresponds to IP Traceroute
       [RFC792] [RFC4443].

       Note that the RPC operation presented in this document is the base
       building block, which is used to derive a model for a technology-
       specific OAM (i.e., ICMP Ping [RFC792] [RFC4443] and Label Switched
       Path (LSP) Ping [RFC8029]).  This base building block should be
       extended with corresponding technology-specific parameters.  To
       facilitate this for future enhancements to data retrieval methods,
       the RPCs are captured under a separate module.

       The generic 'tp-address' grouping is used as data input from
       different RPCs described in this document.  The generic 'path-
       discovery-data' and 'continuity-check-data' groupings defined by the
       "ietf-connectionless-oam.yang" module [RFC8532] are used as data
       outputs from different RPCs described in this document.  Similar
       methods, including other RPCs, can retrieve the data using the same
       data model (i.e., the "ietf-connectionless-oam.yang" module).

            rpc continuity-check {
             if-feature cl-oam:continuity-check;
             description
               "Continuity Check RPC operation as per RFC 7276.";
             reference
               "RFC 7276: An Overview of Operations, Administration, and
                Maintenance (OAM) Tools";
             input {
             uses rpc-input-parameters;
             ....
             }
           output {
             container response-info {
               leaf protocol-id {
                 type identityref {
                   base protocol-id;
                 }
                 mandatory true;
                 description
                   "Protocol used in the Continuity Check. ";
               }
               leaf protocol-id-meta-data {
                  type identityref {
                   base protocol-id-meta-data;
                   }
                    description
                    "An optional metadata related to the protocol ID.";
               }
               leaf status-code {

    Kumar, et al.                Standards Track                    [Page 5]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

                 type identityref{
                base status-code;
              }
                 mandatory true;
                 description
                   "Status code for Continuity Check RPC operation.";
               }
               leaf status-sub-code {
                 type identityref{
                 base status-sub-code;
              }
                 mandatory true;
                 description
                   "Status-sub-code for Continuity Check RPC operation.";
               }
               description
                 "Status code and status-sub-code for Continuity Check RPC
                  operation.";
             }
             uses cl-oam:continuity-check-data;
           }
         }

           rpc path-discovery {
             description
               "Path discovery RPC operation as per RFC 7276.";
             reference
               "RFC 7276: An Overview of Operations, Administration, and
                Maintenance (OAM) Tools";
             input {
             uses rpc-input-parameters;
             .....
             }
           output {
             list response-list {
               key "response-index";
               description
                 "Path discovery response list.";
               leaf response-index {
                 type uint32;
                 mandatory true;
                 description
                   "Response index.";
               }
               leaf protocol-id {
                 type identityref {
                   base protocol-id;
                 }

    Kumar, et al.                Standards Track                    [Page 6]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

                 mandatory true;
                 description
                   "Protocol used in path discovery. ";
               }
               leaf protocol-id-meta-data {
                  type identityref {
                   base protocol-id-meta-data;
                   }
                    description
                    "An optional metadata related to the protocol ID.";
               }
               leaf status-code {
                 type identityref{
                 base status-code;
               }
                 mandatory true;
                 description
                   "Status code for path discovery RPC operation. ";
               }
               leaf status-sub-code {
                 type identityref{
                 base status-sub-code;
              }
                 mandatory true;
                 description
                   "Status-sub-code for path discovery RPC operation. ";
               }
             }
             uses cl-oam:path-discovery-data;
           }
         }

                Snippet of Data Hierarchy Related to RPC Operations

    3.2.  OAM Retrieval Methods Hierarchy

       The complete data hierarchy related to the Connectionless OAM
       Retrieval Methods YANG data model is presented below.

       module: ietf-connectionless-oam-methods

         rpcs:
           +---x continuity-check {cl-oam:continuity-check}?
           |  +---w input
           |  |  +---w destination-tp
           |  |  |  +---w tp-location-type    identityref
           |  |  |  +---w mac-address
           |  |  |  |  +---w mac-address    yang:mac-address

    Kumar, et al.                Standards Track                    [Page 7]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

           |  |  |  +---w ipv4-address
           |  |  |  |  +---w ipv4-address    inet:ipv4-address
           |  |  |  +---w ipv6-address
           |  |  |  |  +---w ipv6-address    inet:ipv6-address
           |  |  |  +---w tp-attribute
           |  |  |  |  +---w tp-attribute-type?
           |  |  |  |  |       address-attribute-type
           |  |  |  |  +---w (tp-attribute-value)?
           |  |  |  |     +--:(ip-prefix)
           |  |  |  |     |  +---w ip-prefix?
           |  |  |  |     |          inet:ip-prefix
           |  |  |  |     +--:(bgp)
           |  |  |  |     |  +---w bgp?
           |  |  |  |     |          inet:ip-prefix
           |  |  |  |     +--:(tunnel)
           |  |  |  |     |  +---w tunnel-interface?         uint32
           |  |  |  |     +--:(pw)
           |  |  |  |     |  +---w remote-pe-address?
           |  |  |  |     |  |       inet:ip-address
           |  |  |  |     |  +---w pw-id?                    uint32
           |  |  |  |     +--:(vpls)
           |  |  |  |     |  +---w route-distinguisher?
           |  |  |  |     |  |       rt:route-distinguisher
           |  |  |  |     |  +---w sender-ve-id?             uint16
           |  |  |  |     |  +---w receiver-ve-id?           uint16
           |  |  |  |     +--:(mpls-mldp)
           |  |  |  |        +---w (root-address)?
           |  |  |  |           +--:(ip-address)
           |  |  |  |           |  +---w source-address?
           |  |  |  |           |  |       inet:ip-address
           |  |  |  |           |  +---w group-ip-address?
           |  |  |  |           |          inet:ip-address
           |  |  |  |           +--:(vpn)
           |  |  |  |           |  +---w as-number?
           |  |  |  |           |          inet:as-number
           |  |  |  |           +--:(global-id)
           |  |  |  |              +---w lsp-id?             string
           |  |  |  +---w system-info
           |  |  |     +---w router-id?   rt:router-id
           |  |  +---w source-interface      if:interface-ref
           |  |  +---w outbound-interface    if:interface-ref
           |  |  +---w vrf?
           |  |  |       cl-oam:routing-instance-ref
           |  |  +---w session-type?         enumeration
           |  |  +---w count?                uint32
           |  |  +---w ttl?                  uint8
           |  |  +---w packet-size?          uint32
           |  +--ro output

    Kumar, et al.                Standards Track                    [Page 8]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

           |     +--ro response-info
           |     |  +--ro protocol-id              identityref
           |     |  +--ro protocol-id-meta-data?   identityref
           |     |  +--ro status-code              identityref
           |     |  +--ro status-sub-code          identityref
           |     +--ro src-test-point
           |     |  +--ro ni?                 routing-instance-ref
           |     |  +--ro tp-location-type    identityref
           |     |  +--ro mac-address
           |     |  |  +--ro mac-address    yang:mac-address
           |     |  +--ro ipv4-address
           |     |  |  +--ro ipv4-address    inet:ipv4-address
           |     |  +--ro ipv6-address
           |     |  |  +--ro ipv6-address    inet:ipv6-address
           |     |  +--ro tp-attribute
           |     |  |  +--ro tp-attribute-type?
           |     |  |  |       address-attribute-type
           |     |  |  +--ro (tp-attribute-value)?
           |     |  |     +--:(ip-prefix)
           |     |  |     |  +--ro ip-prefix?
           |     |  |     |          inet:ip-prefix
           |     |  |     +--:(bgp)
           |     |  |     |  +--ro bgp?
           |     |  |     |          inet:ip-prefix
           |     |  |     +--:(tunnel)
           |     |  |     |  +--ro tunnel-interface?         uint32
           |     |  |     +--:(pw)
           |     |  |     |  +--ro remote-pe-address?
           |     |  |     |  |       inet:ip-address
           |     |  |     |  +--ro pw-id?                    uint32
           |     |  |     +--:(vpls)
           |     |  |     |  +--ro route-distinguisher?
           |     |  |     |  |       rt:route-distinguisher
           |     |  |     |  +--ro sender-ve-id?             uint16
           |     |  |     |  +--ro receiver-ve-id?           uint16
           |     |  |     +--:(mpls-mldp)
           |     |  |        +--ro (root-address)?
           |     |  |           +--:(ip-address)
           |     |  |           |  +--ro source-address?
           |     |  |           |  |       inet:ip-address
           |     |  |           |  +--ro group-ip-address?
           |     |  |           |          inet:ip-address
           |     |  |           +--:(vpn)
           |     |  |           |  +--ro as-number?
           |     |  |           |          inet:as-number
           |     |  |           +--:(global-id)
           |     |  |              +--ro lsp-id?             string
           |     |  +--ro system-info

    Kumar, et al.                Standards Track                    [Page 9]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

           |     |  |  +--ro router-id?   rt:router-id
           |     |  +--ro egress-intf-name?   if:interface-ref
           |     +--ro dest-test-point
           |     |  +--ro ni?                  routing-instance-ref
           |     |  +--ro tp-location-type     identityref
           |     |  +--ro mac-address
           |     |  |  +--ro mac-address    yang:mac-address
           |     |  +--ro ipv4-address
           |     |  |  +--ro ipv4-address    inet:ipv4-address
           |     |  +--ro ipv6-address
           |     |  |  +--ro ipv6-address    inet:ipv6-address
           |     |  +--ro tp-attribute
           |     |  |  +--ro tp-attribute-type?
           |     |  |  |       address-attribute-type
           |     |  |  +--ro (tp-attribute-value)?
           |     |  |     +--:(ip-prefix)
           |     |  |     |  +--ro ip-prefix?
           |     |  |     |          inet:ip-prefix
           |     |  |     +--:(bgp)
           |     |  |     |  +--ro bgp?
           |     |  |     |          inet:ip-prefix
           |     |  |     +--:(tunnel)
           |     |  |     |  +--ro tunnel-interface?         uint32
           |     |  |     +--:(pw)
           |     |  |     |  +--ro remote-pe-address?
           |     |  |     |  |       inet:ip-address
           |     |  |     |  +--ro pw-id?                    uint32
           |     |  |     +--:(vpls)
           |     |  |     |  +--ro route-distinguisher?
           |     |  |     |  |       rt:route-distinguisher
           |     |  |     |  +--ro sender-ve-id?             uint16
           |     |  |     |  +--ro receiver-ve-id?           uint16
           |     |  |     +--:(mpls-mldp)
           |     |  |        +--ro (root-address)?
           |     |  |           +--:(ip-address)
           |     |  |           |  +--ro source-address?
           |     |  |           |  |       inet:ip-address
           |     |  |           |  +--ro group-ip-address?
           |     |  |           |          inet:ip-address
           |     |  |           +--:(vpn)
           |     |  |           |  +--ro as-number?
           |     |  |           |          inet:as-number
           |     |  |           +--:(global-id)
           |     |  |              +--ro lsp-id?             string
           |     |  +--ro system-info
           |     |  |  +--ro router-id?   rt:router-id
           |     |  +--ro ingress-intf-name?   if:interface-ref
           |     +--ro sequence-number?             uint64

    Kumar, et al.                Standards Track                   [Page 10]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

           |     +--ro hop-cnt?                     uint8
           |     +--ro session-packet-statistics
           |     |  +--ro rx-packet-count?    uint32
           |     |  +--ro tx-packet-count?    uint32
           |     |  +--ro rx-bad-packet?      uint32
           |     |  +--ro tx-packet-failed?   uint32
           |     +--ro session-error-statistics
           |     |  +--ro packet-loss-count?          uint32
           |     |  +--ro loss-ratio?                 percentage
           |     |  +--ro packet-reorder-count?       uint32
           |     |  +--ro packets-out-of-seq-count?   uint32
           |     |  +--ro packets-dup-count?          uint32
           |     +--ro session-delay-statistics
           |     |  +--ro time-unit-value?       identityref
           |     |  +--ro min-delay-value?       uint32
           |     |  +--ro max-delay-value?       uint32
           |     |  +--ro average-delay-value?   uint32
           |     +--ro session-jitter-statistics
           |        +--ro unit-value?             identityref
           |        +--ro min-jitter-value?       uint32
           |        +--ro max-jitter-value?       uint32
           |        +--ro average-jitter-value?   uint32
           +---x path-discovery {cl-oam:path-discovery}?
              +---w input
              |  +---w destination-tp
              |  |  +---w tp-location-type    identityref
              |  |  +---w mac-address
              |  |  |  +---w mac-address    yang:mac-address
              |  |  +---w ipv4-address
              |  |  |  +---w ipv4-address    inet:ipv4-address
              |  |  +---w ipv6-address
              |  |  |  +---w ipv6-address    inet:ipv6-address
              |  |  +---w tp-attribute
              |  |  |  +---w tp-attribute-type?
              |  |  |  |       address-attribute-type
              |  |  |  +---w (tp-attribute-value)?
              |  |  |     +--:(ip-prefix)
              |  |  |     |  +---w ip-prefix?
              |  |  |     |          inet:ip-prefix
              |  |  |     +--:(bgp)
              |  |  |     |  +---w bgp?
              |  |  |     |          inet:ip-prefix
              |  |  |     +--:(tunnel)
              |  |  |     |  +---w tunnel-interface?         uint32
              |  |  |     +--:(pw)
              |  |  |     |  +---w remote-pe-address?
              |  |  |     |  |       inet:ip-address
              |  |  |     |  +---w pw-id?                    uint32

    Kumar, et al.                Standards Track                   [Page 11]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

              |  |  |     +--:(vpls)
              |  |  |     |  +---w route-distinguisher?
              |  |  |     |  |       rt:route-distinguisher
              |  |  |     |  +---w sender-ve-id?             uint16
              |  |  |     |  +---w receiver-ve-id?           uint16
              |  |  |     +--:(mpls-mldp)
              |  |  |        +---w (root-address)?
              |  |  |           +--:(ip-address)
              |  |  |           |  +---w source-address?
              |  |  |           |  |       inet:ip-address
              |  |  |           |  +---w group-ip-address?
              |  |  |           |          inet:ip-address
              |  |  |           +--:(vpn)
              |  |  |           |  +---w as-number?
              |  |  |           |          inet:as-number
              |  |  |           +--:(global-id)
              |  |  |              +---w lsp-id?             string
              |  |  +---w system-info
              |  |     +---w router-id?   rt:router-id
              |  +---w source-interface      if:interface-ref
              |  +---w outbound-interface    if:interface-ref
              |  +---w vrf?
              |  |       cl-oam:routing-instance-ref
              |  +---w session-type?         enumeration
              |  +---w max-ttl?              uint8
              +--ro output
                 +--ro response-list* [response-index]
                 |  +--ro response-index           uint32
                 |  +--ro protocol-id              identityref
                 |  +--ro protocol-id-meta-data?   identityref
                 |  +--ro status-code              identityref
                 |  +--ro status-sub-code          identityref
                 +--ro src-test-point
                 |  +--ro ni?                 routing-instance-ref
                 |  +--ro tp-location-type    identityref
                 |  +--ro mac-address
                 |  |  +--ro mac-address    yang:mac-address
                 |  +--ro ipv4-address
                 |  |  +--ro ipv4-address    inet:ipv4-address
                 |  +--ro ipv6-address
                 |  |  +--ro ipv6-address    inet:ipv6-address
                 |  +--ro tp-attribute
                 |  |  +--ro tp-attribute-type?
                 |  |  |       address-attribute-type
                 |  |  +--ro (tp-attribute-value)?
                 |  |     +--:(ip-prefix)
                 |  |     |  +--ro ip-prefix?
                 |  |     |          inet:ip-prefix

    Kumar, et al.                Standards Track                   [Page 12]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

                 |  |     +--:(bgp)
                 |  |     |  +--ro bgp?
                 |  |     |          inet:ip-prefix
                 |  |     +--:(tunnel)
                 |  |     |  +--ro tunnel-interface?         uint32
                 |  |     +--:(pw)
                 |  |     |  +--ro remote-pe-address?
                 |  |     |  |       inet:ip-address
                 |  |     |  +--ro pw-id?                    uint32
                 |  |     +--:(vpls)
                 |  |     |  +--ro route-distinguisher?
                 |  |     |  |       rt:route-distinguisher
                 |  |     |  +--ro sender-ve-id?             uint16
                 |  |     |  +--ro receiver-ve-id?           uint16
                 |  |     +--:(mpls-mldp)
                 |  |        +--ro (root-address)?
                 |  |           +--:(ip-address)
                 |  |           |  +--ro source-address?
                 |  |           |  |       inet:ip-address
                 |  |           |  +--ro group-ip-address?
                 |  |           |          inet:ip-address
                 |  |           +--:(vpn)
                 |  |           |  +--ro as-number?
                 |  |           |          inet:as-number
                 |  |           +--:(global-id)
                 |  |              +--ro lsp-id?             string
                 |  +--ro system-info
                 |     +--ro router-id?   rt:router-id
                 +--ro dest-test-point
                 |  +--ro ni?                 routing-instance-ref
                 |  +--ro tp-location-type    identityref
                 |  +--ro mac-address
                 |  |  +--ro mac-address    yang:mac-address
                 |  +--ro ipv4-address
                 |  |  +--ro ipv4-address    inet:ipv4-address
                 |  +--ro ipv6-address
                 |  |  +--ro ipv6-address    inet:ipv6-address
                 |  +--ro tp-attribute
                 |  |  +--ro tp-attribute-type?
                 |  |  |       address-attribute-type
                 |  |  +--ro (tp-attribute-value)?
                 |  |     +--:(ip-prefix)
                 |  |     |  +--ro ip-prefix?
                 |  |     |          inet:ip-prefix
                 |  |     +--:(bgp)
                 |  |     |  +--ro bgp?
                 |  |     |          inet:ip-prefix
                 |  |     +--:(tunnel)

    Kumar, et al.                Standards Track                   [Page 13]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

                 |  |     |  +--ro tunnel-interface?         uint32
                 |  |     +--:(pw)
                 |  |     |  +--ro remote-pe-address?
                 |  |     |  |       inet:ip-address
                 |  |     |  +--ro pw-id?                    uint32
                 |  |     +--:(vpls)
                 |  |     |  +--ro route-distinguisher?
                 |  |     |  |       rt:route-distinguisher
                 |  |     |  +--ro sender-ve-id?             uint16
                 |  |     |  +--ro receiver-ve-id?           uint16
                 |  |     +--:(mpls-mldp)
                 |  |        +--ro (root-address)?
                 |  |           +--:(ip-address)
                 |  |           |  +--ro source-address?
                 |  |           |  |       inet:ip-address
                 |  |           |  +--ro group-ip-address?
                 |  |           |          inet:ip-address
                 |  |           +--:(vpn)
                 |  |           |  +--ro as-number?
                 |  |           |          inet:as-number
                 |  |           +--:(global-id)
                 |  |              +--ro lsp-id?             string
                 |  +--ro system-info
                 |     +--ro router-id?   rt:router-id
                 +--ro sequence-number?             uint64
                 +--ro hop-cnt?                     uint8
                 +--ro session-packet-statistics
                 |  +--ro rx-packet-count?    uint32
                 |  +--ro tx-packet-count?    uint32
                 |  +--ro rx-bad-packet?      uint32
                 |  +--ro tx-packet-failed?   uint32
                 +--ro session-error-statistics
                 |  +--ro packet-loss-count?          uint32
                 |  +--ro loss-ratio?                 percentage
                 |  +--ro packet-reorder-count?       uint32
                 |  +--ro packets-out-of-seq-count?   uint32
                 |  +--ro packets-dup-count?          uint32
                 +--ro session-delay-statistics
                 |  +--ro time-unit-value?       identityref
                 |  +--ro min-delay-value?       uint32
                 |  +--ro max-delay-value?       uint32
                 |  +--ro average-delay-value?   uint32
                 +--ro session-jitter-statistics
                 |  +--ro unit-value?             identityref
                 |  +--ro min-jitter-value?       uint32
                 |  +--ro max-jitter-value?       uint32
                 |  +--ro average-jitter-value?   uint32
                 +--ro path-verification

    Kumar, et al.                Standards Track                   [Page 14]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

                 |  +--ro flow-info?
                 |  |       string
                 |  +--ro session-path-verification-statistics
                 |     +--ro verified-count?   uint32
                 |     +--ro failed-count?     uint32
                 +--ro path-trace-info
                    +--ro path-trace-info-list* [index]
                       +--ro index                   uint32
                       +--ro ni?
                       |       routing-instance-ref
                       +--ro tp-location-type        identityref
                       +--ro mac-address
                       |  +--ro mac-address    yang:mac-address
                       +--ro ipv4-address
                       |  +--ro ipv4-address    inet:ipv4-address
                       +--ro ipv6-address
                       |  +--ro ipv6-address    inet:ipv6-address
                       +--ro tp-attribute
                       |  +--ro tp-attribute-type?
                       |  |       address-attribute-type
                       |  +--ro (tp-attribute-value)?
                       |     +--:(ip-prefix)
                       |     |  +--ro ip-prefix?
                       |     |          inet:ip-prefix
                       |     +--:(bgp)
                       |     |  +--ro bgp?
                       |     |          inet:ip-prefix
                       |     +--:(tunnel)
                       |     |  +--ro tunnel-interface?
                       |     |          uint32
                       |     +--:(pw)
                       |     |  +--ro remote-pe-address?
                       |     |  |       inet:ip-address
                       |     |  +--ro pw-id?
                       |     |          uint32
                       |     +--:(vpls)
                       |     |  +--ro route-distinguisher?
                       |     |  |       rt:route-distinguisher
                       |     |  +--ro sender-ve-id?
                       |     |  |       uint16
                       |     |  +--ro receiver-ve-id?
                       |     |          uint16
                       |     +--:(mpls-mldp)
                       |        +--ro (root-address)?
                       |           +--:(ip-address)
                       |           |  +--ro source-address?
                       |           |  |       inet:ip-address
                       |           |  +--ro group-ip-address?

    Kumar, et al.                Standards Track                   [Page 15]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

                       |           |          inet:ip-address
                       |           +--:(vpn)
                       |           |  +--ro as-number?
                       |           |          inet:as-number
                       |           +--:(global-id)
                       |              +--ro lsp-id?
                       |                      string
                       +--ro system-info
                       |  +--ro router-id?   rt:router-id
                       +--ro timestamp-type?         identityref
                       +--ro timestamp-64bit
                       |  +--ro timestamp-sec?       uint32
                       |  +--ro timestamp-nanosec?   uint32
                       +--ro timestamp-80bit {ptp-long-format}?
                       |  +--ro timestamp-sec?       uint64
                       |  +--ro timestamp-nanosec?   uint32
                       +--ro ntp-timestamp-32bit
                       |       {ntp-short-format}?
                       |  +--ro timestamp-sec?       uint16
                       |  +--ro timestamp-nanosec?   uint16
                       +--ro icmp-timestamp-32bit {icmp-timestamp}?
                       |  +--ro timestamp-millisec?   uint32
                       +--ro ingress-intf-name?
                       |       if:interface-ref
                       +--ro egress-intf-name?
                       |       if:interface-ref
                       +--ro queue-depth?            uint32
                       +--ro transit-delay?          uint32
                       +--ro app-meta-data?          uint64

                      Data Hierarchy of OAM Retrieval Methods

    4.  OAM Retrieval Methods YANG Module

       <CODE BEGINS> file
          "ietf-connectionless-oam-methods@2019-04-16.yang"

    module ietf-connectionless-oam-methods {
      namespace
        "urn:ietf:params:xml:ns:yang:ietf-connectionless-oam-methods";
      prefix cloam-methods;

      import ietf-interfaces {
        prefix if;
      }
      import ietf-connectionless-oam {
        prefix cl-oam;
      }

    Kumar, et al.                Standards Track                   [Page 16]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

      organization
        "IETF LIME Working Group";
      contact
        "WG Web:   <https://datatracker.ietf.org/wg/lime>
         WG List:  <mailto:lmap@ietf.org>

         Deepak Kumar <dekumar@cisco.com>
         Qin Wu <bill.wu@huawei.com>
         Srihari Raghavan <rihari@cisco.com>
         Michael Wang <wangzitao@huawei.com>
         Reshad Rahman <rrahman@cisco.com>";
      description
        "This YANG module defines the RPC operations for
         connectionless OAM to be used within the IETF
         in a protocol-independent manner.  It is
         assumed that each protocol maps corresponding
         abstracts to its native format.  Each protocol
         may extend the YANG data model defined here to
         include protocol-specific extensions.

         Copyright (c) 2019 IETF Trust and the persons identified as
         authors of the code.  All rights reserved.

         Redistribution and use in source and binary forms, with or
         without modification, is permitted pursuant to, and subject
         to the license terms contained in, the Simplified BSD License
         set forth in Section 4.c of the IETF Trust's Legal Provisions
         Relating to IETF Documents
         (http://trustee.ietf.org/license-info).

         This version of this YANG module is part of RFC 8533; see
         the RFC itself for full legal notices.";

      revision 2019-04-16 {
        description
          "Initial revision.";
        reference
          "RFC 8533: Retrieval Methods YANG Data Model for the Management
           of Operations, Administration, and Maintenance (OAM)
           Protocols That Use Connectionless Communications";
      }

      identity protocol-id {
        description
          "This is the base identity for a generic protocol
           ID.  The protocol registry can be found at
           https://www.iana.org/protocols.";
      }

    Kumar, et al.                Standards Track                   [Page 17]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

      identity protocol-id-internet {
        base protocol-id;
        description
          "Identity for Internet Protocols.";
      }

      identity protocol-id-proprietary {
        base protocol-id;
        description
          "Identity for proprietary protocols (e.g.,
           IP SLA).";
      }

      identity protocol-id-sfc {
        base protocol-id;
        description
          "Identity for Service Function Chaining.";
      }

      identity protocol-id-mpls {
        base protocol-id;
        description
          "The MPLS protocol.";
      }

      identity protocol-id-mpls-tp {
        base protocol-id;
        description
          "The MPLS-TP protocol.";
      }

      identity protocol-id-twamp {
        base protocol-id;
        description
          "The Two-Way Active Measurement Protocol (TWAMP)
           protocol.";
      }

      identity protocol-id-bier {
        base protocol-id;
        description
          "The Bit Index Explicit Replication (BIER)
           protocol.";
      }

      identity status-code {
        description
          "This is base identity for a status code.";

    Kumar, et al.                Standards Track                   [Page 18]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

      }

      identity success-reach {
        base status-code;
        description
          "Indicates that the destination being verified
           is reachable (see RFC 7276).";
        reference
          "RFC 7276: An Overview of Operations, Administration, and
           Maintenance (OAM) Tools";
      }

      identity fail-reach {
        base status-code;
        description
          "Indicates that the destination being verified
           is not reachable (see RFC 7276).";
        reference
          "RFC 7276: An Overview of Operations, Administration, and
           Maintenance (OAM) Tools";
      }

      identity success-path-verification {
        base status-code;
        description
          "Indicates that the path verification is performed
           successfully (see RFC 7276).";
        reference
          "RFC 7276: An Overview of Operations, Administration, and
           Maintenance (OAM) Tools";
      }

      identity fail-path-verification {
        base status-code;
        description
          "Indicates that the path verification fails
           (see RFC 7276).";
        reference
          "RFC 7276: An Overview of Operations, Administration, and
           Maintenance (OAM) Tools";
      }

      identity status-sub-code {
        description
          "IdentityBase status-sub-code.";
      }

      identity invalid-cc {

    Kumar, et al.                Standards Track                   [Page 19]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

        base status-sub-code;
        description
          "Indicates that the Continuity Check message is invalid
           (see RFC 7276).";
        reference
          "RFC 7276: An Overview of Operations, Administration, and
           Maintenance (OAM) Tools";
      }

      identity invalid-pd {
        base status-sub-code;
        description
          "Indicates that the path discovery message is invalid
           (see RFC 7276).";
        reference
          "RFC 7276: An Overview of Operations, Administration, and
           Maintenance (OAM) Tools";
      }

      identity protocol-id-meta-data {
        description
          "This is the base identity for metadata that corresponds
           to the protocol ID.";
      }

      identity protocol-internet-number {
        base protocol-id-meta-data;
        description
          "Internet Protocol number for standard
           Internet Protocols (IANA-assigned Internet
           Protocol numbers) to help in protocol processing.
           The Protocol Numbers registry can be found at
           https://www.iana.org/assignments/protocol-numbers.";
      }

      grouping rpc-input-parameters {
        container destination-tp {
          uses cl-oam:tp-address;
          description
            "Destination test point.";
        }
        leaf source-interface {
          type if:interface-ref;
          mandatory true;
          description
            "Source interface.";
        }
        leaf outbound-interface {

    Kumar, et al.                Standards Track                   [Page 20]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

          type if:interface-ref;
          mandatory true;
          description
            "Outbound interface.";
        }
        leaf vrf {
          type cl-oam:routing-instance-ref;
          description
            "Virtual Routing and Forwarding (VRF) instance.";
        }
        description
          "Grouping for RPC input parameters";
      }

      rpc continuity-check {
        if-feature "cl-oam:continuity-check";
        description
          "Continuity Check RPC operation as per RFC 7276.";
        reference
          "RFC 7276: An Overview of Operations, Administration, and
           Maintenance (OAM) Tools";
        input {
          uses rpc-input-parameters;
          uses cl-oam:session-type {
            description
              "If session-type is specified, then session-type
                  must be set to on demand";
          }
          leaf count {
            type uint32 {
              range "0..4294967295" {
                description
                  "The overall number of packets to be transmitted
                   by the sender.  The value of the count will be set
                   to zero (0) on creation and will thereafter
                   increase monotonically until it reaches a maximum
                   value of 2^32-1 (4294967295 decimal), when it wraps
                   around and starts increasing again from zero.";
              }
            }
            default "5";
            description
              "Specifies the number of
               packets that will be sent.  By
               default, the packet number is
               set to 5.";
          }
          leaf ttl {

    Kumar, et al.                Standards Track                   [Page 21]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

            type uint8;
            default "255";
            description
              "Time to live (TTL) used to limit the lifetime
               of data packets transmitted in the network
               to prevent looping.  The TTL value is decremented
               for every hop that the packet traverses.  If the
               TTL is zero, the data packet will be discarded.";
          }
          leaf packet-size {
            type uint32 {
              range "64..10000";
            }
            default "64";
            description
              "Packet size of the Continuity Check message, in octets.
               By default, the packet size is set to 64 octets.";
          }
        }
        output {
          container response-info {
            leaf protocol-id {
              type identityref {
                base protocol-id;
              }
              mandatory true;
              description
                "Protocol used in the Continuity Check message.
                 This could be a standard protocol (e.g.,
                 TCP/IP protocols, MPLS, etc.) or a proprietary
                 protocol as identified by this field.";
            }
            leaf protocol-id-meta-data {
              type identityref {
                base protocol-id-meta-data;
              }
              description
                "An optional metadata related to the protocol ID.
                 For example, this could be the Internet Protocol
                 number for standard Internet Protocols used for
                 help with protocol processing.";
            }
            leaf status-code {
              type identityref {
                base status-code;
              }
              mandatory true;
              description

    Kumar, et al.                Standards Track                   [Page 22]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

                "Status code for Continuity Check RPC operation.
                 This could be a basic status code (e.g., destination
                 is reachable or destination is not reachable; see RFC 7276)
                 or some customized status code as identified by this
                 field.";
              reference
                "RFC 7276: An Overview of Operations, Administration, and
                 Maintenance (OAM) Tools";
            }
            leaf status-sub-code {
              type identityref {
                base status-sub-code;
              }
              mandatory true;
              description
                "An optional status-sub-code for Continuity Check
                 RPC operation.  If the basic status code is destination
                 reachable, this status-sub-code doesn't need to be
                 specified.  If the basic status code is destination
                 unreachable, the status-sub-code can be used to specify
                 the detailed reasons.  This could be a basic
                 sub-status-code (such as an invalid Continuity Check) or
                 other error codes specific to the protocol under use for
                 the Continuity Checks.  For example, if ICMP is the
                 protocol under use, the error codes defined in RFC 4443
                 can be used to specify the reasons specific to ICMP.
                 This technology-specific status-sub-code can be
                 defined in technology-specific models.";
              reference
                "RFC 4443: The IETF Administrative Oversight Committee
                 (IAOC) Member Selection Guidelines and Process.";
            }
            description
              "Status code and status-sub-code for Continuity Check RPC
               operation.";
          }
          uses cl-oam:continuity-check-data;
        }
      }

      rpc path-discovery {
        if-feature "cl-oam:path-discovery";
        description
          "Path discovery RPC operation as per RFC 7276.";
        reference
          "RFC 7276: An Overview of Operations, Administration, and
           Maintenance (OAM) Tools";
        input {

    Kumar, et al.                Standards Track                   [Page 23]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

          uses rpc-input-parameters;
          uses cl-oam:session-type {
            description
              "If session-type is specified, then session-type
                must be set to on demand";
          }
          leaf max-ttl {
            type uint8;
            default "255";
            description
              "Maximum TTL indicates the maximum number of hops that
               a packet is permitted to travel before being discarded
               by a router.  By default, the maximum TTL is set to
               255.";
          }
        }
        output {
          list response-list {
            key "response-index";
            description
              "Path discovery response list.";
            leaf response-index {
              type uint32;
              mandatory true;
              description
                "Response index.";
            }
            leaf protocol-id {
              type identityref {
                base protocol-id;
              }
              mandatory true;
              description
                "Protocol used in path discovery.  This could be a
                 standard protocol (e.g., TCP/IP protocols, MPLS, etc.)
                 or a proprietary protocol as identified by
                 this field.";
            }
            leaf protocol-id-meta-data {
              type identityref {
                base protocol-id-meta-data;
              }
              description
                "An optional metadata related to the protocol ID.
                 For example, this could be the Internet Protocol
                 number for standard Internet Protocols used for
                 help with protocol processing.";
            }

    Kumar, et al.                Standards Track                   [Page 24]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

            leaf status-code {
              type identityref {
                base status-code;
              }
              mandatory true;
              description
                "Status code for Continuity Check RPC operation.
                 This could be a basic status code (e.g., destination
                 is reachable or destination is not reachable) or some
                 customized status code as identified by this field.";
            }
            leaf status-sub-code {
              type identityref {
                base status-sub-code;
              }
              mandatory true;
              description
                "An optional status-sub-code for Continuity Check
                 RPC operation.  If the basic status code is destination
                 reachable, this status-sub-code doesn't need to be
                 specified.  If the basic status code is destination
                 unreachable, the status-sub-code can be used to specify
                 the detailed reasons.  This could be a basic
                 sub-status-code (such as an invalid Continuity Check) or
                 other error codes specific to the protocol under use for
                 Continuity Checks.  For example, if ICMP is the protocol
                 under use, the error codes defined in RFC 4443
                 can be used to specify the reasons specific to ICMP.
                 This technology-specific status-sub-code can be defined
                 in technology-specific models.";
              reference
                "RFC 4443: The IETF Administrative Oversight Committee
                 (IAOC) Member Selection Guidelines and Process.";
            }
          }
          uses cl-oam:path-discovery-data;
        }
      }
    }

    <CODE ENDS>

    Kumar, et al.                Standards Track                   [Page 25]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

    5.  Security Considerations

       The YANG module specified in this document defines a schema for data
       that is designed to be accessed via network management protocols such
       as NETCONF [RFC6241] or RESTCONF [RFC8040].  The lowest NETCONF layer
       is the secure transport layer, and the mandatory-to-implement secure
       transport is Secure Shell (SSH) [RFC6242].  The lowest RESTCONF layer
       is HTTPS, and the mandatory-to-implement secure transport is TLS
       [RFC8446].

       The Network Configuration Access Control Model (NACM) [RFC8341]
       provides the means to restrict access for particular NETCONF or
       RESTCONF users to a preconfigured subset of all available NETCONF or
       RESTCONF protocol operations and content.

       Some of the RPC operations in this YANG module may be considered
       sensitive or vulnerable in some network environments.  It is thus
       important to control access to these operations.  These are the
       operations and their sensitivity/vulnerability:

       o  continuity-check: Generates Continuity Check.

       o  path-discovery: Generates path discovery.

       These operations are used to retrieve the data from the device that
       needs to execute the OAM command.  Unauthorized source access to some
       sensitive information in the above data may be used for network
       reconnaissance or lead to denial-of-service attacks on both the local
       device and the network.

    6.  IANA Considerations

       This document registers a URI in the "IETF XML Registry" [RFC3688].
       The following registration has been made:

       URI: urn:ietf:params:xml:ns:yang:ietf-connectionless-oam-methods
       Registrant Contact: The IESG.  XML: N/A, the requested URI is an XML
       namespace.

       This document registers a YANG module in the "YANG Module Names"
       registry [RFC6020].

       name: ietf-connectionless-oam-methods
       namespace:
          urn:ietf:params:xml:ns:yang:ietf-connectionless-oam-methods
       prefix: cloam-methods
       reference: RFC 8533

    Kumar, et al.                Standards Track                   [Page 26]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

    7.  References

    7.1.  Normative References

       [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
                  DOI 10.17487/RFC3688, January 2004,
                  <https://www.rfc-editor.org/info/rfc3688>.

       [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
                  the Network Configuration Protocol (NETCONF)", RFC 6020,
                  DOI 10.17487/RFC6020, October 2010,
                  <https://www.rfc-editor.org/info/rfc6020>.

       [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
                  and A. Bierman, Ed., "Network Configuration Protocol
                  (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
                  <https://www.rfc-editor.org/info/rfc6241>.

       [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
                  Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
                  <https://www.rfc-editor.org/info/rfc6242>.

       [RFC7011]  Claise, B., Ed., Trammell, B., Ed., and P. Aitken,
                  "Specification of the IP Flow Information Export (IPFIX)
                  Protocol for the Exchange of Flow Information", STD 77,
                  RFC 7011, DOI 10.17487/RFC7011, September 2013,
                  <https://www.rfc-editor.org/info/rfc7011>.

       [RFC792]   Postel, J., "Internet Control Message Protocol", STD 5,
                  RFC 792, DOI 10.17487/RFC0792, September 1981.

       [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
                  Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
                  <https://www.rfc-editor.org/info/rfc8040>.

       [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
                  Access Control Model", STD 91, RFC 8341,
                  DOI 10.17487/RFC8341, March 2018,
                  <https://www.rfc-editor.org/info/rfc8341>.

       [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
                  Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
                  <https://www.rfc-editor.org/info/rfc8446>.

    Kumar, et al.                Standards Track                   [Page 27]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

       [RFC8532]  Kumar, D., Wang, M., Wu, Q., Ed., Rahman, R., and
                  S. Raghavan, "Generic YANG Data Model for the Management of
                  Operations, Administration, and Maintenance (OAM)
                  Protocols That Use Connectionless Communications",
                  RFC 8532, DOI 10.17487/RFC8532, April 2019,
                  <https://www.rfc-editor.org/info/rfc8532>.

    7.2.  Informative References

       [RFC4443]  Conta, A., Deering, S., and M. Gupta, Ed., "Internet
                  Control Message Protocol (ICMPv6) for the Internet
                  Protocol Version 6 (IPv6) Specification", STD 89,
                  RFC 4443, DOI 10.17487/RFC4443, March 2006,
                  <https://www.rfc-editor.org/info/rfc4443>.

       [RFC5880]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
                  (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
                  <https://www.rfc-editor.org/info/rfc5880>.

       [RFC7276]  Mizrahi, T., Sprecher, N., Bellagamba, E., and Y.
                  Weingarten, "An Overview of Operations, Administration,
                  and Maintenance (OAM) Tools", RFC 7276,
                  DOI 10.17487/RFC7276, June 2014,
                  <https://www.rfc-editor.org/info/rfc7276>.

       [RFC8029]  Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
                  Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
                  Switched (MPLS) Data-Plane Failures", RFC 8029,
                  DOI 10.17487/RFC8029, March 2017,
                  <https://www.rfc-editor.org/info/rfc8029>.

       [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215,
                  RFC 8340, DOI 10.17487/RFC8340, March 2018,
                  <https://www.rfc-editor.org/info/rfc8340>.

       [RFC8407]  Bierman, A., "Guidelines for Authors and Reviewers of
                  Documents Containing YANG Data Models", BCP 216, RFC 8407,
                  DOI 10.17487/RFC8407, October 2018,
                  <https://www.rfc-editor.org/info/rfc8407>.

       [YANG-Push]
                  Clemm, A., Voit, E., Prieto, A., Tripathy, A., Nilsen-
                  Nygaard, E., Bierman, A., and B. Lengyel, "Subscription to
                  YANG Datastores", Work in Progress, draft-ietf-netconf-
                  yang-push-22, February 2019.

    Kumar, et al.                Standards Track                   [Page 28]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

    Appendix A.  Extending Connectionless OAM Method Module Example

       The following is an example of extensions possible to the
       "ietf-connectionless-oam-methods" YANG data model defined in this document.

       The snippet below depicts an example of augmenting the
       "ietf-connectionless-oam-methods" YANG data model with ICMP ping
       attributes:

       augment "/cloam-methods:continuity-check"
       +"/cloam-methods:output"{
         container session-rtt-statistics{
          leaf min-rtt{
           type uint32;
        description
        "This minimum ping round-trip-time (RTT) received.";
          }
          leaf max-rtt{
           type uint32;
        description
        "This maximum ping RTT received.";
          }
          leaf avg-rtt{
           type uint32;
        description
         "The current average ping RTT.";
          }
          description
          "This container presents the ping RTT statistics.";
         }
       }

    A.1.  Example of New Retrieval Procedures Model

       As discussed in the Introduction section of this document, the new
       retrieval procedures can be defined for retrieval of the same data
       defined by the base YANG data model for connectionless OAM protocols.
       This appendix demonstrates how the base connectionless OAM data model
       can be extended to support persistent data retrieval besides
       on-demand retrieval procedures defined in Section 3, i.e., first
       retrieve a persistent-id based on the destination test point location
       information, and then retrieve the export details based on
       persistent-id.  Internet Protocol Flow Information Export (IPFIX)
       [RFC7011] or YANG-Push [YANG-Push] are currently outlined here as
       data export options.  Additional export options can be added in the
       future.

    Kumar, et al.                Standards Track                   [Page 29]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

       The YANG module "example-cl-oam-persistent-methods" shown below is
       intended as an illustration rather than a real definition of an RPC
       operation model for persistent data retrieval.  For the sake of
       brevity, this module does not obey all the guidelines specified in
       [RFC8407].

       module example-cl-oam-persistent-methods {
         namespace "http://example.com/cl-oam-persistent-methods";
         prefix pcloam-methods;

         import ietf-interfaces {
           prefix if;
         }
         import ietf-connectionless-oam {
           prefix cl-oam;
         }
         import ietf-yang-types {
           prefix yang;
         }

         identity export-method {
           description
             "Base identity to represent a conceptual
              export-method.";
         }

         identity ipfix-export {
           base export-method;
           description
             "IPFIX-based export.  Configuration provided
              separately.";
         }

         identity yang-push-export {
           base export-method;
           description
             "YANG-Push from draft-ietf-netconf-yang-push.";
         }

         identity protocol-id {
           description
             "A generic protocol identifier.";
         }

         identity status-code {
           description
             "Base status code.";
         }

    Kumar, et al.                Standards Track                   [Page 30]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

         identity success-reach {
           base status-code;
           description
             "Indicates that the destination being verified
              is reachable.";
         }

         identity fail-reach {
           base status-code;
           description
             "Indicates that the destination being verified
              is not reachable";
         }

         identity success-path-verification {
           base status-code;
           description
             "Indicates that the path verification is performed
              successfully.";
         }

         identity fail-path-verification {
           base status-code;
           description
             "Indicates that the path verification fails.";
         }

         identity status-sub-code {
           description
             "Base status-sub-code.";
         }

         identity invalid-cc {
           base status-sub-code;
           description
             "Indicates that the Continuity Check message is
              invalid.";
         }

         identity invalid-pd {
           base status-sub-code;
           description
             "Indicates that the path discovery message is invalid.";
         }

         typedef export-method {
           type identityref {
             base export-method;

    Kumar, et al.                Standards Track                   [Page 31]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

           }
           description
             "Export method type.";
         }

         typedef change-type {
           type enumeration {
             enum create {
               description
                 "Change due to a create.";
             }
             enum delete {
               description
                 "Change due to a delete.";
             }
             enum modify {
               description
                 "Change due to an update.";
             }
           }
           description
             "Different types of changes that may occur.";
         }

         rpc cc-get-persistent-id {
           if-feature "cl-oam:continuity-check";
           description
             "Obtains Continuity Check persistent identification
              given mapping parameters as input.";
           input {
             container destination-tp {
               uses cl-oam:tp-address;
               description
                 "Destination test point.";
             }
             uses cl-oam:session-type;
             leaf source-interface {
               type if:interface-ref;
               description
                 "Source interface.";
             }
             leaf outbound-interface {
               type if:interface-ref;
               description
                 "Outbound interface.";
             }
             leaf vrf {
               type cl-oam:routing-instance-ref;

    Kumar, et al.                Standards Track                   [Page 32]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

               description
                 "VRF instance.";
             }
           }
           output {
             container error-code {
               leaf protocol-id {
                 type identityref {
                   base protocol-id;
                 }
                 mandatory true;
                 description
                   "Protocol used.  This could be a standard
                    protocol (e.g., TCP/IP protocols, MPLS, etc.)
                    or a proprietary protocol as identified by
                    this field.";
               }
               leaf protocol-id-meta-data {
                 type uint64;
                 description
                   "An optional metadata related to the protocol ID.
                    For example, this could be the Internet Protocol
                    number for standard Internet Protocols used for
                    help with protocol processing.";
               }
               leaf status-code {
                 type identityref {
                   base status-code;
                 }
                 mandatory true;
                 description
                   "Status code.";
               }
               leaf status-sub-code {
                 type identityref {
                   base status-sub-code;
                 }
                 mandatory true;
                 description
                   "Sub code for the Continuity Check.";
               }
               description
                 "Status code and sub code.";
             }
             leaf cc-persistent-id {
               type string;
               description
                 "Id to act as a cookie.";

    Kumar, et al.                Standards Track                   [Page 33]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

             }
           }
         }

         rpc cc-persistent-get-export-details {
           if-feature "cl-oam:continuity-check";
           description
             "Given the persistent ID, gets the configuration
              options and details related to the configured data
              export.";
           input {
             leaf cc-persistent-id {
               type string;
               description
                 "Persistent ID for use as a key in search.";
             }
           }
           output {
             container error-code {
               leaf protocol-id {
                 type identityref {
                   base protocol-id;
                 }
                 mandatory true;
                 description
                   "Protocol used.  This could be a standard
                    protocol (e.g., TCP/IP protocols, MPLS, etc.)
                    or a proprietary protocol as identified by
                    this field.";
               }
               leaf protocol-id-meta-data {
                 type uint64;
                 description
                   "An optional metadata related to the protocol ID.
                    For example, this could be the Internet Protocol
                    number for standard Internet Protocols used for
                    help with protocol processing.";
               }
               leaf status-code {
                 type identityref {
                   base status-code;
                 }
                 mandatory true;
                 description
                   "Status code.";
               }
               leaf status-sub-code {
                 type identityref {

    Kumar, et al.                Standards Track                   [Page 34]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

                   base status-sub-code;
                 }
                 mandatory true;
                 description
                   "Sub code for the Continuity Check.";
               }
               description
                 "Status code and sub code.";
             }
             leaf data-export-method {
               type export-method;
               description
                 "Type of export in use.";
             }
             choice cc-trigger {
               description
                 "Necessary conditions for
                  periodic or on-change trigger.";
               case periodic {
                 description
                   "Periodic reports.";
                 leaf period {
                   type yang:timeticks;
                   description
                     "Time interval between reports.";
                 }
                 leaf start-time {
                   type yang:date-and-time;
                   description
                     "Timestamp from which reports were started.";
                 }
               }
               case on-change {
                 description
                   "On-change trigger and not periodic.";
                 leaf all-data-on-start {
                   type boolean;
                   description
                     "Full update done on start or not.";
                 }
                 leaf-list excluded-change {
                   type change-type;
                   description
                     "Changes that will not trigger an update.";
                 }
               }
             }
           }

    Kumar, et al.                Standards Track                   [Page 35]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

         }

         rpc pd-get-persistent-id {
           if-feature "cl-oam:path-discovery";
           description
             "Obtains persistent path discovery identification.";
           input {
             container destination-tp {
               uses cl-oam:tp-address;
               description
                 "Destination test point.";
             }
             uses cl-oam:session-type;
             leaf source-interface {
               type if:interface-ref;
               description
                 "Source interface.";
             }
             leaf outbound-interface {
               type if:interface-ref;
               description
                 "Outbound interface.";
             }
             leaf vrf {
               type cl-oam:routing-instance-ref;
               description
                 "VRF";
             }
           }
           output {
             list response-list {
               key "response-index";
               description
                 "Path discovery response list.";
               leaf response-index {
                 type uint32;
                 mandatory true;
                 description
                   "Response index.";
               }
               leaf protocol-id {
                 type identityref {
                   base protocol-id;
                 }
                 mandatory true;
                 description
                   "Protocol used.  This could be a standard
                    protocol (e.g., TCP/IP protocols, MPLS, etc.)

    Kumar, et al.                Standards Track                   [Page 36]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

                    or a proprietary protocol as identified by
                    this field.";
               }
               leaf protocol-id-meta-data {
                 type uint64;
                 description
                   "An optional metadata related to the protocol ID.
                    For example, this could be the Internet Protocol
                    number for standard Internet Protocols used for
                    help with protocol processing.";
               }
               leaf status-code {
                 type identityref {
                   base status-code;
                 }
                 mandatory true;
                 description
                   "Status code for persistent path discovery
                    information.";
               }
               leaf status-sub-code {
                 type identityref {
                   base status-sub-code;
                 }
                 mandatory true;
                 description
                   "Sub code for persistent path discovery
                    information.";
               }
               leaf pd-persistent-id {
                 type string;
                 description
                   "Id to act as a cookie.";
               }
             }
           }
         }

         rpc pd-persistent-get-export-details {
           if-feature "cl-oam:path-discovery";
           description
             "Given the persistent ID, gets the configuration
              options and details related to the configured data
              export.";
           input {
             leaf cc-persistent-id {
               type string;
               description

    Kumar, et al.                Standards Track                   [Page 37]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

                 "Persistent ID for use as a key in search.";
             }
           }
           output {
             list response-list {
               key "response-index";
               description
                 "Path discovery response list.";
               leaf response-index {
                 type uint32;
                 mandatory true;
                 description
                   "Response index.";
               }
               leaf protocol-id {
                 type identityref {
                   base protocol-id;
                 }
                 mandatory true;
                 description
                   "Protocol used.  This could be a standard
                    protocol (e.g., TCP/IP protocols, MPLS, etc.)
                    or a proprietary protocol as identified by
                    this field.";
               }
               leaf protocol-id-meta-data {
                 type uint64;
                 description
                   "An optional metadata related to the protocol ID.
                    For example, this could be the Internet Protocol
                    number for standard Internet Protocols used for
                    help with protocol processing.";
               }
               leaf status-code {
                 type identityref {
                   base status-code;
                 }
                 mandatory true;
                 description
                   "Status code for persistent path discovery
                    creation.";
               }
               leaf status-sub-code {
                 type identityref {
                   base status-sub-code;
                 }
                 mandatory true;
                 description

    Kumar, et al.                Standards Track                   [Page 38]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

                   "Sub code for persistent path discovery
                    creation.";
               }
               leaf data-export-method {
                 type export-method;
                 description
                   "Type of export.";
               }
               choice pd-trigger {
                 description
                   "Necessary conditions
                    for periodic or on-change
                    trigger.";
                 case periodic {
                   description
                     "Periodic reports.";
                   leaf period {
                     type yang:timeticks;
                     description
                       "Time interval between reports.";
                   }
                   leaf start-time {
                     type yang:date-and-time;
                     description
                       "Timestamp from which reports are started.";
                   }
                 }
                 case on-change {
                   description
                     "On-change trigger and not periodic.";
                   leaf all-data-on-start {
                     type boolean;
                     description
                       "Full update done on start or not.";
                   }
                   leaf-list excluded-change {
                     type change-type;
                     description
                       "Changes that will not trigger an update.";
                   }
                 }
               }
             }
           }
         }
       }

    Kumar, et al.                Standards Track                   [Page 39]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

    Acknowledgements

       The authors of this document would like to thank Elwyn Davies, Alia
       Atlas, Brian E. Carpenter, Greg Mirsky, Adam Roach, Alissa Cooper,
       Eric Rescorla, Ben Campbell, Benoit Claise, Kathleen Moriarty, Carlos
       Pignataro, Benjamin Kaduk, and others for their substantive review,
       comments, and proposals to improve the document.

    Kumar, et al.                Standards Track                   [Page 40]

    RFC 8533         YANG Model for CL OAM Retrieval Methods      April 2019

    Authors' Addresses

       Deepak Kumar
       CISCO Systems
       510 McCarthy Blvd.
       Milpitas, CA  95035
       United States of America

       Email: dekumar@cisco.com

       Michael Wang
       Huawei Technologies, Co., Ltd
       101 Software Avenue, Yuhua District
       Nanjing  210012
       China

       Email: wangzitao@huawei.com

       Qin Wu (editor)
       Huawei
       101 Software Avenue, Yuhua District
       Nanjing, Jiangsu  210012
       China

       Email: bill.wu@huawei.com

       Reshad Rahman
       CISCO Systems
       2000 Innovation Drive
       Kanata, Ontario  K2K 3E8
       Canada

       Email: rrahman@cisco.com

       Srihari Raghavan
       CISCO Systems
       Tril Infopark Sez, Ramanujan IT City
       Neville Block, 2nd floor, Old Mahabalipuram Road
       Chennai, Tamil Nadu  600113
       India

       Email: srihari@cisco.com

    Kumar, et al.                Standards Track                   [Page 41]