Network Working Group D. Allen Internet-Draft IPTC Expires: Nov, 2003 May,2003 URN Namespace for NewsML Resources draft-allen-newsml-urn-rfc3085bis-00.txt. Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on Nov, 2003. Copyright Notice Copyright (C) The Internet Society (2000). All Rights Reserved. Abstract This document describes a URN (Uniform Resource Name) namespace for identifying NewsML NewsItems and NewsML related XML Schemas. A NewsItem is an information resource that is expressible as a NewsML element within a NewsML document conforming to the NewsML Document Type Declaration (DTD) as defined by the International Press Tele- communications Council (IPTC). Allen Expires Nov, 2003 [Page 1] Internet-Draft URN Namespace for NewsML May, 2003 1. Introduction NewsML is an XML format for packaging multimedia news resources. It has been created under the auspices of the International Press Telecommunications Council (IPTC), and version 1.0 was approved by the IPTC on 6 October 2000. The same logical NewsItem may exist in multiple physical locations. The NewsML specification allows NewsItems to have multiple URLs, but only a single URN. It is the latter which then uniquely names the resource. This document obsoletes RFC 3085 (see Appendix A). This namespace specification is for a formal namespace. 2. Specification Template Namespace ID: "newsml" requested. Registration Information: Registration Version Number: 1 Registration Date: 2002-12-07 Declared registrant of the namespace: Name: International Press Telecommunications Council Address: Royal Albert House Sheet Street Windsor SL4 1BE Contact: David Allen m_director_iptc@iptc.org Allen Expires Nov, 2003 [Page 2] Internet-Draft URN Namespace for NewsML May, 2003 Declaration of syntactic structure: The identifier has the following ABNF[6] specification: (1) Either NSS = ProviderId ":" DateId ":" NewsItemId ":" RevisionId Update ProviderId = string DateId = date NewsItemId = string RevisionId = posint Update = 0*1( "A" / "U" ) date = century year month day century = ( "0" posdig ) / ( posdig DIGIT ) year = 2DIGIT month = ( 0 posdig ) / ( "1" ( "0" "1" "2" ) ) day = ( 0 posdig ) / ( ( "1" / "2" ) DIGIT ) / "30" / "31" string = 1*char char = ALPHA / DIGIT / symbol / escape symbol = "(" / ")" / "+" / "," / "-" / "." / "=" / "@" / ";" / "$" / "_" / "!" / "*" / "'" escape = "%" HEXDIG HEXDIG posint = posdig *DIGIT posdig = "1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9" The ProviderId must be an Internet domain name, and must be owned by the organisation creating the NewsML resource and allocating the URN to it, at the date identified by the DateId. DateId is a date in ISO 8601 Basic Format (CCYYMMDD), and must correspond to a date at which the organisation allocating the URN owned the domain name specified in the ProviderId. The NewsItemId must be unique among all NewsItems emanating from the same provider and having the same DateId. RevisionId is a positive integer indicating which revision of a given NewsItem this is. Any positive integer may be used, but it must always be the case that of two instances of a NewsItem that have the same ProviderId, DateId and NewsItemId, the one whose RevisionId has the larger value must be the more recent revision. A RevisionId of 0 is not permitted. If the NewsItem contains an "Update" element or elements, then Update must be set to "U". If the NewsItem consists only of a replacement set of NewsManagement data, then Update must be set to "A". If neither of these is the case, then Update must be suppressed. Allen Expires Nov, 2003 [Page 3] Internet-Draft URN Namespace for NewsML May, 2003 Or (2) - this is the form used for identifying an XML schema NSS = ProviderId ":" DateId ":" FormatName ProviderId = string DateId = date FormatName = string date = century year month day century = ( "0" posdig ) / ( posdig DIGIT ) year = 2DIGIT month = ( 0 posdig ) / ( "1" ( "0" "1" "2" ) ) day = ( 0 posdig ) / ( ( "1" / "2" ) DIGIT ) / "30" / "31" string = 1*char char = ALPHA / DIGIT / symbol / escape symbol = "(" / ")" / "+" / "," / "-" / "." / "=" / "@" / ";" / "$" / "_" / "!" / "*" / "'" escape = "%" HEXDIG HEXDIG The ProviderId must be an Internet domain name, and must be owned by the organisation creating the NewsML resource and allocating the URN to it, at the date identified by the DateId. In this case the allowed value is iptc.org DateId is a date in ISO 8601 Basic Format (CCYYMMDD), and must correspond to a date at which the organisation allocating the URN owned the domain name specified in the ProviderId. The FormatName must be unique among all FormatNames emanating from the same provider and having the same DateId. Initial FormatNames declared are NewsML, NITF and SportsML Relevant ancillary documentation: Definition of domain names, found in: P. Mockapetris, "DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION", RFC1035, November 1987. Definition of NewsML structure found in: "NewsML Functional Specification" 24 October 2000 published by IPTC Allen Expires Nov, 2003 [Page 4] Internet-Draft URN Namespace for NewsML May, 2003 Identifier uniqueness considerations: The combination of ProviderId and DateId serves to uniquely identify the organisation that is allocating the URN. That organisation is responsible for ensuring the uniqueness of the DateId/NewsItemId/RevisionId combination or the FormatName. Uniqueness is guaranteed as long as the assigned string is never reassigned for a given FQDN, and that the FQDN is never reassigned. N.B.: operationally, there is nothing that prevents a domain name from being reassigned; indeed, it is not an uncommon occurrence. This is one of the reasons that this example makes a poor URN namespace in practice, and is therefore not seriously being proposed as it stands. Identifier persistence considerations: A NewsML URN may only be allocated by an organisation that owns an Internet domain name. The URN identifies a date on which the organisation owned that domain name. The combination of date and domain name will serve to uniquely identify that organisation for all time. Process of identifier assignment: The organisation identified by the ProviderId/DateId combination is responsible for allocating a NewsItemId that is unique among all those that it allocates with that DateId. Process of identifier resolution: NewsML providers are responsible for the provision of a URN resolution service, if any, for NewsML URNs they have assigned with a valid ProviderId/DateId combination. Rules for Lexical Equivalence: URNs are lexically equivalent if the ProviderId, DateId, NewsItemId, and RevisionId are all identical (case-insensitive comparison). Conformance with URN Syntax: No special considerations beyond the syntax herein described. Allen Expires Nov, 2003 [Page 5] Internet-Draft URN Namespace for NewsML May, 2003 Validation mechanism: Organisations that allocate NewsML URNs are responsible for the provision of a URN validation service, if any, for URNs they have assigned with a valid ProviderId/DateId combination. Scope: Global (Option (1)). The Option (2) of this specification will be used by the International Press Telecommunications Council to define namespaces for its XML based news exchange Schema such as NewsML, NITF and SportsML etc. 3. Examples The following examples are representative of NewsML URNs, but may not refer to actual resources. urn:newsml:iptc.org:20001006:NewsMLv1.0:1 urn:newsml:reuters.com:20000206: IIMFFH05643_2000-02-06_17-54-01_L06156584:1U or urn:newsml:iptc.org:20001006:NewsML 4. Namespace Considerations RFC 3085 was designed to support the operational use of NewsML and allow news providers to assign unique identifiers to NewsItems transporting news content. Since the introduction of the XML Schema it is necessary to provide a mechanism for allowing other news formats to be imported into the NewsML structure in a way that allows proper validation. The updated definition in this document specifies an alternate form of the NewsML URN NID that may be used to assign identifiers to these XML formats and to NewsML itself. 5. Security Considerations There are no additional security considerations other than those normally associated with the use and resolution of URNs in general. Allen Expires Nov, 2003 [Page 6] Internet-Draft URN Namespace for NewsML May, 2003 6. Community Considerations. The NewsML user community is moving towards the adoption of XML Schema and the use of XML formats for marking up content that is not suited to a pure textual form such as that in W3C XHTML or IPTC News Industry Text Format (NITF). At present there is no consistent way in which to refer to these other namespaces that may need to be included within NewsML and are required to be identified in a manner that allows proper validation of the complete document instance. The introduction of a additional new form of the newsml URN designed to identify such XML Schema will provide such a mechanism. This will enable users to properly resolve the relevant namespaces to identify the Schemas in a consistent fashion. 7. IANA Considerations This RFC includes an extended URN NID registration that is to be entered into the IANA registry of URN NIDs. The NID string "newsml" is requested. This was previously assigned under RFC 3085 and meets the IETF constraints for URN naming. References [1] Rivers-Moore, D., "NewsML Version 1.0 Functional Specification", November 2000, . [2] Rivers-Moore, D., "NewsML Version 1.0 DTD", November 2000, . [3] W3C, XML WG, "Extensible Markup Language (XML) 1.0", February 1998, . [4] Moats, R., "URN Syntax", RFC 2141, May 1997. [5] Daigle, L., van Gulik, D., Iannella, R. and P. Faltstrom, "URN Namespace Definition Mechanisms", RFC YYYY, 2002. [6] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, November 1997. Allen Expires Nov, 2003 [Page 7] Internet-Draft URN Namespace for NewsML May, 2003 Author's Address David Allen IPTC Royal Albert House Sheet Street Windsor SL4 1BE United Kingdom Phone: +44 17 53 70 50 51 EMail: m_director_iptc@iptc.org Internet-Draft URN Namespace for NewsML May, 2003 Appendix A Reasons for Issue of New RFC RFC 3085 issued in March 2001 specified the URN to be used when identifying individual NewsML NewsItems. Since that time the use of XML Schemas has become more common and it is now necessary to provide a modified form of the original newsml URN to enable individual Schemas to be properly identified. This new RFC seeks to address this issue by: 1. Introducing a new alternative form of the newsml URN definition. 2. Updating the original definition to meet the new RFC template recently issued by the IETF.(RFC YYYY) Full Copyright Statement Copyright (C) The Internet Society (2001). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS 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. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Allen Expires Nov, 2003 [Page 8]