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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


   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   and ISBN namespaces, which are now outdated because the descriptions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

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RFC 8254               URN Registration Transition          October 2017

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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RFC 8254               URN Registration Transition          October 2017

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]

   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

   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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RFC 8254               URN Registration Transition          October 2017

   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

   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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RFC 8254               URN Registration Transition          October 2017

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,

8.2.  Informative References

              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",

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RFC 8254               URN Registration Transition          October 2017

              ISBN International Agency, "Namespace Registration for
              International Standard Book Number (ISBN) ISO 2108:2017",
              June 2017,

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

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

              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 International Centre, "Namespace Registration for
              International Standard Serial Number (ISSN) and Linking
              ISSN (ISSN-L) based on ISO 3297:2007", June 2017,

   [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,

   [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,

   [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,

   [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,


   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.


   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

   Email: juha.hakala@helsinki.fi

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