path: root/doc/rfc/rfc3937.txt

Network Working Group                                          M. Steidl
Request for Comments: 3937                                          IPTC
Category: Informational                                     October 2004


             A Uniform Resource Name (URN) Namespace for
       the International Press Telecommunications Council (IPTC)

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2004).

Abstract

   This document describes a URN (Uniform Resource Name) namespace for
   identifying persistent resources published by the International Press
   Telecommunications Council (IPTC).  These resources include XML Data
   Type Definition files (DTD), XML Schema, Namespaces in XML, XSL
   stylesheets, other XML based document and documents of other data
   formats like PDF documents, Microsoft Office documents and others.

























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Table of Contents

   1.  Introduction. . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  IANA URN Specification Template . . . . . . . . . . . . . . .   3
       2.1.  Namespace ID. . . . . . . . . . . . . . . . . . . . . .   3
       2.2.  Registration Information. . . . . . . . . . . . . . . .   3
       2.3.  Declaration of syntactic structure. . . . . . . . . . .   3
       2.4.  Relevant ancillary documentation. . . . . . . . . . . .   5
       2.5.  Identifier uniqueness considerations. . . . . . . . . .   5
       2.6.  Identifier persistence considerations . . . . . . . . .   5
       2.7.  Process of identifier assignment. . . . . . . . . . . .   5
       2.8.  Process for identifier resolution . . . . . . . . . . .   5
       2.9.  Rules for Lexical Equivalence . . . . . . . . . . . . .   5
       2.10. Conformance with URN Syntax . . . . . . . . . . . . . .   5
       2.11. Validation mechanism. . . . . . . . . . . . . . . . . .   5
       2.12. Scope . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Examples. . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Namespace Considerations and Community Considerations . . . .   6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   7.  References. . . . . . . . . . . . . . . . . . . . . . . . . .   7
       7.1.  Normative References. . . . . . . . . . . . . . . . . .   7
       7.2.  Informative References. . . . . . . . . . . . . . . . .   7
   Author's Address. . . . . . . . . . . . . . . . . . . . . . . . .   8
   Full Copyright Statement. . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   The International Press Telecommunications Council (IPTC) is a non-
   profit consortium of the world's major news agencies and news
   industry vendors.  It develops and maintains technical standards for
   the news business that are used by virtually every major news
   organization in the world.  IPTC was established in 1965.

   Since the 1990's IPTC's standardization work is based on open
   standards like first SGML, then the XML [W3CXML] family of standards,
   MIME, Unicode, and so on.

   As some of these standards require identification of resources IPTC
   was looking for a technology for globally unique, persistent and
   location-independent identifiers and decided to implement URNs as
   described in "URN Syntax" [RFC2141] for this reason.

   This namespace specification is for a formal namespace.







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2.  IANA URN Specification Template

2.1.  Namespace ID

   "iptc" requested.

2.2.  Registration Information

   Registration Version Number: 1
   Registration Date: 2003-11-11

      Declared registrant of the namespace:

   Registering organization:
      International Press Telecommunications Council IPTC
      Royal Albert House
      Sheet Street
      Windsor, Berkshire SL4 1BE
      www.iptc.org

   Designated contact person:
      Michael Steidl
      Managing Director
      mdirector@iptc.org

2.3.  Declaration of syntactic structure

   All URNs assigned by IPTC will have a Namespace Specific String (NSS)
   of the following hierarchical structure:

   At the top of the hierarchy are three branches:
   - "std"
   - "std-draft"
   - "workdoc"

   The "std" branch hierarchy:

      The "std" branch URNs will be assigned to IPTC resources
      used for specifying and explaining any aspect of an IPTC
      standard.

      The NSS in the "std" branch will have this general structure:

      urn:iptc:std:{std-name}:{std-version}:{res-group}
          {:res-name}?{:res-version}?






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      where
      "std-name" is a unique identifier for an IPTC standard.
      "std-version" reflects the version of this standard.  The value
          'current' will be assigned to point at resources of the
          current version of a standard.
      "res-group": this field will take only three values:
         "spec" for all resources specifying a standard,
         "doc" for all resources used for additional documentation of
             and to support the use of a standard.
         "xmlns" for defining an XML namespace [W3CXMLNS].
      "res-name" is an identifier for a tangible resource; the name
      should describe the content or the use of the resource.  Since not
      all resources are tangible this value is optional.
      "res-version" reflects the version of this resource as long as it
      takes a physical format - like e.g., a file.  Since not all
      resources are of a physical kind this value is optional.

   The "std-draft" branch hierarchy:

      The "std-draft" branch URNs will be assigned to IPTC resources
      used for specifying and explaining any aspect of an IPTC standard
      while being in draft status, that is at a time when the resource
      is not formally approved by the IPTC Standards body.

      The NSS in the "std" branch will have this general structure:

      urn:iptc:std-draft:{std-name}:{std-version}:{res-group}
          {:res-name}?{:res-version}?

      The substructure of "urn:iptc:std-draft" is identical to that of
      "urn:iptc:std", find all explanations there.

   The "workdoc" branch hierarchy:

      The "workdoc" branch URNs will be assigned to IPTC resources not
      directly related to IPTC standards but to the work of IPTC.

      The NSS in the "doc" branch will have this general structure:

      urn:iptc:workdoc:{group-id}:{doc-id}:{doc-version}{:doc-descr}?

      where
      "group-id" is a unique identifier for working groups and working
         areas of IPTC and constitutes a document group.
      "doc-id" is a unique identifier for a document within a document
          group.





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      "doc-version" reflects the version of this work document.
      "doc-descr" is an optional concise description of the document
          content.

2.4.  Relevant ancillary documentation

   None

2.5.  Identifier uniqueness considerations

   Identifier uniqueness will be enforced by the Managing Director of
   IPTC who will assign unique identifiers to all resources identified
   by a URN.

2.6.  Identifier persistence considerations

   IPTC is committed to maintaining the accessibility and persistence of
   all resources that are identified by an IPTC URN.

2.7.  Process of identifier assignment

   Assignment is limited to the owner of this namespace and its
   authorities.

2.8.  Process for identifier resolution

   IPTC will develop an appropriate mechanism that maps all assigned
   URNs to Uniform Resource Locators (URL), specifically to enable web
   based resolution of URNs.

2.9.  Rules for Lexical Equivalence

   No special considerations, the rules for lexical equivalence of RFC
   2141 apply.

2.10.  Conformance with URN Syntax

   No special considerations.

2.11.  Validation mechanism

   None specified.  IPTC will develop a mechanism for resolving URNs to
   URLs (see 2.8), this mechanism will also show whether a URN is valid.

2.12.  Scope

   Global.




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3.  Examples

   The following examples are representative for IPTC URNs, but may not
   refer to actual resources.

   urn:iptc:std:NewsML:1.1:spec:DTD:1
      DTD version 1 to specify the IPTC standard "NewsML", version 1.1

   urn:iptc:std-draft:NITF:3.5:spec:xml-schema:2
      Second draft XML Schema  for the IPTC standard "NITF", version 3.5

   urn:iptc:std:SportsML:1.0:xmlns
      URN to identify an XML namespace for the IPTC standard "SportsML",
      version 1.0.  No "res-name" and "res-version" since an XML
      namespace is of no physical format.

   urn:iptc:std:NewsML:1.1:doc:news-agency-guidelines:1.2
      Supporting document named "news-agency-guidelines", version 1,
      revision 2, based on the IPTC standard "NewsML" version 1.1.

   urn:iptc:workdoc:NMA:0315:1:srs-terms
      Work document of IPTC's News Metadata Working Party (NMA), version
      1, holding terms of the Subject Reference System

4.  Namespace Considerations and Community Considerations

   The IPTC acknowledged already the use of URNs during the development
   of its XML based standard "NewsML".  This standard implements the use
   of URNs as unique identifiers for news items as described in "URN
   Namespace for NewsML resources" [RFC3085].

   While developing additional XML based standards as siblings to
   NewsML, IPTC soon got aware that URNs have to be assigned to
   resources that fall beyond the scope of the NewsML namespace.  For
   this reason IPTC developed a new and very general hierarchical
   namespace structure to cover the needs of the currently developed
   standards as well as future standards and to be able to assign URNs
   to resources emanating from them.

   In addition to resources relating directly to its standards, IPTC
   also produces and publishes other documents relevant to the news
   business.  As those resources are used by many organizations outside
   the IPTC membership and therefore could not be considered as internal
   documents IPTC decided to add a branch to the URN hierarchy to be
   assigned to these resources.






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   IPTC maintains global activities and its standards as well as
   resources based on them are used world wide.  Since one focus of the
   activities of IPTC is on global exchange of news any system for
   unique identification of resources has to be considered under global
   aspects.

   For this reason IPTC considers the introduction of a URN namespace
   for its resources as proper action to maintain globally unique,
   persistent and location-independent identifiers based on open
   standards.

5.  Security Considerations

   There are no additional security considerations other than those
   normally associated with the use and resolution of URNs in general.

6.  IANA Considerations

   This document includes a URN Namespace registration that conforms to
   the "Uniform Resources Names (URN) Namespace Definition Mechanism"
   [RFC3406] and has been entered into the IANA registry for URN NIDs.

7.  References

7.1.  Normative References

   [RFC2141]  Moats, R., "URN Syntax", RFC 2141, May 1997.

   [RFC3406]  Daigle, L., van Gulik, D., Iannella, R. and P. Faltstrom,
              "Uniform Resource Names (URN) Namespace Definition
              Mechanisms", BCP 66, RFC 3406, October 2002.

7.2.  Informative References

   [W3CXML]   W3C, XML WG, "Extensible Markup Language (XML) 1.0" (Third
              Edition), February 2004, <http://www.w3.org/TR/REC-xml>.

   [W3CXMLNS] W3C, Namespaces WG, "Namespaces in XML", January 1999,
              <http://www.w3.org/TR/REC-xml-names>.

   [RFC3085]  Coates, A., Allen, D. and D. Rivers-Moore, "URN Namespace
              for NewsML Resources", RFC 3085, March 2001.









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Author's Address

   Michael Steidl
   IPTC (International Press Telecommunications Council)
   Royal Albert House
   Sheet Street
   Windsor SL4 1BE
   United Kingdom

   Phone: +44 (1753) 705 051
   EMail: mdirector@iptc.org








































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Full Copyright Statement

   Copyright (C) The Internet Society (2004).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
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Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.







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