    Internet Engineering Task Force (IETF)                        J. Klensin
    Request for Comments: 8254
    Obsoletes: 3044, 3187                                          J. Hakala
    Category: Standards Track                The National Library of Finland
    ISSN: 2070-1721                                             October 2017

         Uniform Resource Name (URN) Namespace Registration Transition

    Abstract

       The original registration procedure for formal Uniform Resource Name
       (URN) namespaces required IETF Consensus.  That requirement
       discouraged some registrations and increased the risk for problems
       that could occur as a result.  The requirements have now been changed
       by RFC 8141, which adopts a different model, focusing on encouraging
       registration and publication of information for all appropriate
       namespaces.  This document clarifies the status of relevant older
       RFCs and confirms and documents advice to IANA about selected
       existing registrations.  This document also obsoletes RFCs 3044 and
       3187 and moves them to Historic status.  These RFCs describe the ISSN
       and ISBN namespaces, which are now outdated because the descriptions
       reside in registration templates.

    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/rfc8254.

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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
       (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.  Obsoleting Older Registration RFCs for ISSNs and ISBNs  . . .   4
         2.1.  ISBN URN Changes  . . . . . . . . . . . . . . . . . . . .   4
         2.2.  ISSN URN Changes  . . . . . . . . . . . . . . . . . . . .   4
       3.  The Older Registration RFC for NBNs . . . . . . . . . . . . .   5
       4.  Other Existing URN Registrations and RFCs . . . . . . . . . .   5
       5.  Registration Examples . . . . . . . . . . . . . . . . . . . .   5
       6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
       7.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
       8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
         8.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
         8.2.  Informative References  . . . . . . . . . . . . . . . . .   6
       Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   8
       Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .   8
       Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

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    1.  Introduction

       As a part of the initial development of the Uniform Resource Name
       (URN) system in the late 1990s, the IETF URN Working Group agreed
       that it was important to demonstrate that the URN syntax could
       accommodate existing identifier systems.  RFC 2288 [RFC2288] showed
       the feasibility of using International Standard Book Number (ISBN),
       International Standard Serial Number (ISSN), and Serial Item and
       Contribution Identifier (SICI) [ANSI-SICI] as URNs; however, it did
       not formally register corresponding URN namespaces.  This was in part
       due to the still-evolving process to formalize criteria for namespace
       definition documents and registration, consolidated later by the IETF
       into successive Namespace Definition Mechanism documents [RFC2611]
       [RFC3406].

       URN namespaces were subsequently registered for ISBN [RFC3187] and
       ISSN [RFC3044] as well as for a fairly large collection of other
       identifiers including National Bibliography Number (NBN) [RFC3188].
       The comprehensive list can be found in the IANA Uniform Resource
       Names (URN) Namespaces registry [IANA-URN] (see also Section 4).

       While a URN namespace for SICI could be registered at any time, the
       SICI standard has not gained broad international acceptance and has
       not had a namespace defined to date.

       The predecessor registration procedure for URN namespaces [RFC3406]
       required IETF Consensus for formal namespaces.  That requirement
       discouraged some registrations and increased the risk for problems,
       including use of names without registration ("squatting").  If names
       are not registered in a consistent way, there is a possibility of the
       same name being used to identify different namespaces with different
       rules, resulting in considerable confusion.  The requirements have
       now been changed in RFC 8141 [RFC8141] to adopt a different model
       that focuses more on encouraging registration of all namespaces that
       follow the formal namespace syntax, with as much information
       collected as possible consistent with that goal.

       Therefore, this document does the following:

       o  Describes the instructions developed with IANA to adapt selected
          existing registrations to the new model.  Those registration
          updates have been completed for ISBN and ISSN Namespace
          Identifiers (NIDs) and URN namespaces.

       o  Obsoletes the separate RFCs that specify the namespaces for ISSNs
          and ISBNs to eliminate any ambiguity about the status of new
          templates and updated registrations.

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       o  Provides information about the status of NBNs under the new
          definitions.

       o  Provides suggestions to IANA about the handling of other existing
          registrations not explicitly discussed in this document.

    2.  Obsoleting Older Registration RFCs for ISSNs and ISBNs

       The existing RFCs that describe URN namespaces for ISSNs [RFC3044]
       and ISBNs [RFC3187] have been identified as "Historic" concurrent
       with publication of this document.  The new registration templates
       for those namespaces have already been submitted and incorporated
       into the URN Namespaces registry by IANA.

       Those updated templates reflect not only the new template formats but
       substantive changes to the definitions of the namespaces.  The
       significant changes are summarized in the subsections that follow.

       For both ISSN and ISBN namespaces, URN registration practices within
       them are expected to evolve along with the ISO ISBN and ISSN
       standards without requiring resubmission of the templates or other
       formal IETF or IANA URN namespace registration update approval
       procedures.  The subsections that follow clarify the relationship
       between the original URN namespace registrations for ISBN and ISSN
       and the recently registered templates that follow the principles of
       RFC 8141.  Approval and registration of those new templates made the
       older templates obsolete.

    2.1.  ISBN URN Changes

       The revised ISBN namespace reflects the latest version of the ISO
       ISBN standard, ISO 2108:2017 [ISO-ISBN-b].  The namespace allows for
       the use of both the old ten-character ISBN numbers described in RFC
       3187 and ISO 2108:1992 [ISO-ISBN-a] (formerly known as ISBN-10) and
       the thirteen-character identifiers introduced in ISO 2108:2005
       [ISO-ISBN-c] (formerly known as ISBN-13).

       For more details, review the new ISBN registration template and
       associated documentation [ISBN-Template].

    2.2.  ISSN URN Changes

       The updated ISSN namespace reflects the changes between the current
       ISSN standard [ISO-ISSN] and its predecessor on which RFC 3044 was
       based.  ISO 3297:2007 introduced the linking ISSN (ISSN-L), which is
       designated for all media of a serial publication, irrespective of how
       many there are.  Traditional ISSN applies to a single medium only,
       such as the printed version of a serial.

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       For more details, review the new ISSN registration template and
       associated documentation [ISSN-Template].

    3.  The Older Registration RFC for NBNs

       NBN is not a formal international standard or even a single
       identifier system but an umbrella concept that covers all of the
       identifier systems the adopting national libraries and their partners
       use to identify resources that do not have other identifiers.  For
       instance, if a book received via legal deposit does not have an ISBN,
       the national library gives it a local identifier.  The NBN
       specification provides a simple means of expressing these local
       identifiers so that they become globally unique URNs, such as
       urn:nbn:fi-fe19981001.

       In addition to the namespace registration itself, RFC 3188 provides
       some generic information about NBNs and their use and specifies the
       syntax of URN:NBNs.  That syntax guarantees uniqueness by requiring
       the usage of country codes and institutional identifiers as a part of
       the Namespace Specific String (NSS).  When RFC 3188 is revised, it
       should be accompanied with a template that revises the registration
       of the URN:NBN namespace.

    4.  Other Existing URN Registrations and RFCs

       The RFC Series and the IANA URN Namespaces registry contain many URN
       namespace registrations in addition to those for which this document
       calls out explicit actions.  In general, those existing registrations
       are still appropriate but omit some information called for in RFC
       8141 [RFC8141].  Reregistration with new templates is recommended but
       not required.  Until and unless those registrations are updated as
       provided for in RFC 8141, the existing registration templates should
       be read as not requiring or allowing any features that were not
       allowed and specified by the earlier URN [RFC2141] and registration
       [RFC3406] specifications.

    5.  Registration Examples

       For examples of registrations using the new model and for information
       and help in understanding other parts of this document, review the
       new ISBN and ISSN registration templates [ISBN-Template]
       [ISSN-Template] and associated documentation in the IANA URN
       Namespaces registry.

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    6.  IANA Considerations

       IANA has completed updates for the registry entries for URN ISSN and
       ISBN namespaces to reflect the new templates that are compliant with
       RFC 8141.  With respect to namespaces other than those listed above,
       when registrations and templates are available that conform to the
       newer rules, they may be substituted for the older ones.  However,
       neither this document nor RFC 8141 supersedes any existing
       registrations (those for ISBN and ISSN are superseded by the recently
       registered templates).  Therefore, IANA needs to be prepared to
       maintain a registry whose contents reflect old-style templates for
       some namespaces and the newer ones for others.

       IANA should also note that the portions of the ISBN and ISSN
       registrations that point to ISO Standards are intended to identify
       current versions (which may change) rather than only the versions
       that are active at the time this document is approved (see
       Section 2).  That provision relies on ISO TC 46 and its respective
       registration authorities to maintain stability of URN references
       discussed in this document.

    7.  Security Considerations

       While particular URN namespaces and their registrations might
       conceivably have security implications, this specification merely
       specifies a transition of a set of namespace registrations and does
       not have such implications.  The security implications associated
       with particular namespaces are expected to be listed in registration
       templates as specified in RFC 8141.

    8.  References

    8.1.  Normative References

       [RFC8141]  Saint-Andre, P. and J. Klensin, "Uniform Resource Names
                  (URNs)", RFC 8141, DOI 10.17487/RFC8141, April 2017,
                  <https://www.rfc-editor.org/info/rfc8141>.

    8.2.  Informative References

       [ANSI-SICI]
                  ANSI/NISO, "Serial Item and Contribution Identifier
                  (SICI)", ANSI/NISO Z39.56-1996 (Version 2), August 1996.

       [IANA-URN] IANA, "Uniform Resource Names (URN) Namespaces",
                  <http://www.iana.org/assignments/urn-namespaces>.

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       [ISBN-Template]
                  ISBN International Agency, "Namespace Registration for
                  International Standard Book Number (ISBN) ISO 2108:2017",
                  June 2017,
                  <https://www.iana.org/assignments/urn-formal/isbn>.

       [ISO-ISBN-a]
                  ISO, "Information and documentation - International
                  Standard Book Number (ISBN)", ISO 2108:1992, 1992.

       [ISO-ISBN-b]
                  ISO, "Information and documentation - International
                  Standard Book Number (ISBN)", ISO 2108:2017, 2017.

       [ISO-ISBN-c]
                  ISO, "Information and documentation - International
                  Standard Book Number (ISBN)", ISO 2108:2005, 2005.

       [ISO-ISSN] ISO, "Information and documentation - International
                  Standard Serial Number (ISSN)", ISO 3297:2007, 2007.

       [ISSN-Template]
                  ISSN International Centre, "Namespace Registration for
                  International Standard Serial Number (ISSN) and Linking
                  ISSN (ISSN-L) based on ISO 3297:2007", June 2017,
                  <https://www.iana.org/assignments/urn-formal/issn>.

       [RFC2141]  Moats, R., "URN Syntax", RFC 2141, DOI 10.17487/RFC2141,
                  May 1997, <https://www.rfc-editor.org/info/rfc2141>.

       [RFC2288]  Lynch, C., Preston, C., and R. Daniel, "Using Existing
                  Bibliographic Identifiers as Uniform Resource Names",
                  RFC 2288, DOI 10.17487/RFC2288, February 1998,
                  <https://www.rfc-editor.org/info/rfc2288>.

       [RFC2611]  Daigle, L., van Gulik, D., Iannella, R., and P. Faltstrom,
                  "URN Namespace Definition Mechanisms", BCP 33, RFC 2611,
                  DOI 10.17487/RFC2611, June 1999,
                  <https://www.rfc-editor.org/info/rfc2611>.

       [RFC3044]  Rozenfeld, S., "Using The ISSN (International Serial
                  Standard Number) as URN (Uniform Resource Names) within an
                  ISSN-URN Namespace", RFC 3044, DOI 10.17487/RFC3044,
                  January 2001, <https://www.rfc-editor.org/info/rfc3044>.

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       [RFC3187]  Hakala, J. and H. Walravens, "Using International Standard
                  Book Numbers as Uniform Resource Names", RFC 3187,
                  DOI 10.17487/RFC3187, October 2001,
                  <https://www.rfc-editor.org/info/rfc3187>.

       [RFC3188]  Hakala, J., "Using National Bibliography Numbers as
                  Uniform Resource Names", RFC 3188, DOI 10.17487/RFC3188,
                  October 2001, <https://www.rfc-editor.org/info/rfc3188>.

       [RFC3406]  Daigle, L., van Gulik, D., Iannella, R., and P. Faltstrom,
                  "Uniform Resource Names (URN) Namespace Definition
                  Mechanisms", RFC 3406, DOI 10.17487/RFC3406, October 2002,
                  <https://www.rfc-editor.org/info/rfc3406>.

    Acknowledgements

       This document draws heavily on discussions in the IETF URNbis Working
       Group in the second and third quarters of 2013, particularly during
       IETF 87 in August 2013, and on informal discussions during the
       plenary meeting of ISO TC 46 in June 2013.  The efforts of those who
       participated in those discussions are greatly appreciated.  It also
       draws on Internet-Drafts that were developed to update the older
       registrations before that approach was replaced by the new extended
       template model.  Those documents were prepared by Pierre Godefroy,
       Juha Hakala, Alfred Hoenes, and Maarit Huttunen.

       The current specification benefits significantly from a careful
       reading and suggestions for editorial changes by Peter Saint-Andre;
       from considerable work by Stella Griffiths of the ISBN International
       Agency to refine the ISBN discussion and develop the corresponding
       template; and from Gaelle Bequet, Pierre Godefroy, and Clement Oury
       of the ISSN International Centre for similar refinements of the ISSN
       discussion and template.

    Contributors

       Alfred Hoenes was the editor and co-author of two of the documents
       from which this one is, in part, derived.  This document would not
       have been possible without his contributions.

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    Authors' Addresses

       John C. Klensin
       1770 Massachusetts Ave, Ste 322
       Cambridge, MA  02140
       United States of America

       Phone: +1 617 245 1457
       Email: john-ietf@jck.com

       Juha Hakala
       The National Library of Finland
       P.O. Box 15, Helsinki University
       Helsinki, MA  FIN-00014
       Finland

       Email: juha.hakala@helsinki.fi

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