Internet DRAFT - draft-allen-newsml-urn-rfc3085bis

draft-allen-newsml-urn-rfc3085bis





Network Working Group                                          D. Allen
Internet-Draft                                                     IPTC
Expires: Feb 25, 2003                                 September 24 2002

 
                    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.

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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).


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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 


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   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.


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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



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   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.

  
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 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.


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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,
        <http://www.iptc.org/NewsML/specification/NewsMLv1.0.pdf>.

   [2]  Rivers-Moore, D., "NewsML Version 1.0 DTD", November 2000,
        <http://www.iptc.org/NewsML/DTD/NewsMLv1.0.dtd>.

   [3]  W3C, XML WG, "Extensible Markup Language (XML) 1.0", February
        1998, <http://www.w3.org/TR/REC-xml>.

   [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.


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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             September 2002



    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.

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Acknowledgement

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

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