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Network Working Group                                          M. SteidlRequest for Comments: 3937                                          IPTCCategory: Informational                                     October 2004A Uniform Resource Name (URN) Namespace forthe 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.Steidl                       Informational                      [Page 1]

RFC 3937                 URN Namespace for IPTC             October 2004Table of Contents1.  Introduction. . . . . . . . . . . . . . . . . . . . . . . . .22.  IANA URN Specification Template . . . . . . . . . . . . . . .32.1.  Namespace ID. . . . . . . . . . . . . . . . . . . . . .32.2.  Registration Information. . . . . . . . . . . . . . . .32.3.  Declaration of syntactic structure. . . . . . . . . . .32.4.  Relevant ancillary documentation. . . . . . . . . . . .52.5.  Identifier uniqueness considerations. . . . . . . . . .52.6.  Identifier persistence considerations . . . . . . . . .52.7.  Process of identifier assignment. . . . . . . . . . . .52.8.  Process for identifier resolution . . . . . . . . . . .52.9.  Rules for Lexical Equivalence . . . . . . . . . . . . .52.10. Conformance with URN Syntax . . . . . . . . . . . . . .52.11. Validation mechanism. . . . . . . . . . . . . . . . . .52.12. Scope . . . . . . . . . . . . . . . . . . . . . . . . .53.  Examples. . . . . . . . . . . . . . . . . . . . . . . . . . .64.  Namespace Considerations and Community Considerations . . . .65.  Security Considerations . . . . . . . . . . . . . . . . . . .76.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .77.  References. . . . . . . . . . . . . . . . . . . . . . . . . .77.1.  Normative References. . . . . . . . . . . . . . . . . .77.2.  Informative References. . . . . . . . . . . . . . . . .7   Author's Address. . . . . . . . . . . . . . . . . . . . . . . . .8   Full Copyright Statement. . . . . . . . . . . . . . . . . . . . .91.  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.Steidl                       Informational                      [Page 2]

RFC 3937                 URN Namespace for IPTC             October 20042.  IANA URN Specification Template2.1.  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.org2.3.  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}?Steidl                       Informational                      [Page 3]

RFC 3937                 URN Namespace for IPTC             October 2004      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.Steidl                       Informational                      [Page 4]

RFC 3937                 URN Namespace for IPTC             October 2004      "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   None2.5.  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 ofRFC2141 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.Steidl                       Informational                      [Page 5]

RFC 3937                 URN Namespace for IPTC             October 20043.  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 System4.  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.Steidl                       Informational                      [Page 6]

RFC 3937                 URN Namespace for IPTC             October 2004   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.  References7.1.  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.Steidl                       Informational                      [Page 7]

RFC 3937                 URN Namespace for IPTC             October 2004Author'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.orgSteidl                       Informational                      [Page 8]

RFC 3937                 URN Namespace for IPTC             October 2004Full Copyright Statement   Copyright (C) The Internet Society (2004).   This document is subject to the rights, licenses and restrictions   contained inBCP 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   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.Intellectual Property   The IETF takes no position regarding the validity or scope of any   Intellectual Property Rights or other rights that might be claimed to   pertain to the implementation or use of the technology described in   this document or the extent to which any license under such rights   might or might not be available; nor does it represent that it has   made any independent effort to identify any such rights.  Information   on the IETF's procedures with respect to rights in IETF Documents can   be found inBCP 78 andBCP 79.   Copies of IPR disclosures made to the IETF Secretariat and any   assurances of licenses to be made available, or the result of an   attempt made to obtain a general license or permission for the use of   such proprietary rights by implementers or users of this   specification can be obtained from the IETF on-line IPR repository athttp://www.ietf.org/ipr.   The IETF invites any interested party to bring to its attention any   copyrights, patents or patent applications, or other proprietary   rights that may cover technology that may be required to implement   this standard.  Please address the information to the IETF at ietf-   ipr@ietf.org.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Steidl                       Informational                      [Page 9]