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 (C) The Internet Society (2004).
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.
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.
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:
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.
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.
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.
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