Network Working Group
Request for Comments: 3120
Category: Informational
K. Best
OASIS, Inc.
N. Walsh
Sun Microsystems, Inc.
June 2001

A URN Namespace for XML.org

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 © The Internet Society (2001). All Rights Reserved.

Abstract

This document describes a URN (Uniform Resource Name) namespace that is engineered by the Organization for the Advancement of Structured Information Standards (OASIS) for naming persistent resources stored in the XML.org repository (such as XML (Extensible Markup Language) Document Type Definitions, XML Schemas, Namespaces, Stylesheets, and other documents).

1. Introduction

The XML.org Registry is provided by XML.org as a public service where XML schemas, DTDs, stylesheets, and other documents can be shared. Documents are submitted to a repository then retrieved by others who may want to use them. These documents require unique identifiers.

Motivated by these observations, XML.org would like to assign URNs to some resources in order to retain unique, permanent location- independent names for them.

This namespace specification is for a formal namespace.

2. Specification Template

Namespace ID:

"xmlorg" requested.

Registration Information:

      Registration Version Number: 3
      Registration Date: 2001-02-05

Declared registrant of the namespace:

Karl Best
OASIS - Organization for the Advancement of Structured Information Standards
Post Office Box 455
Billerica, MA USA 01821

      Phone: +1 (978) 667 5115

Declaration of structure:

The Namespace Specific String (NSS) of all URNs assigned by XML.org will have the following hierarchical structure:

There is one branch at the top of the hierarchy: "objects".

      The Objects Hierarchy

The general structure of the NSS in the names hierarchy has the form:

urn:xmlorg:objects:{type}{:subtype}?:{object-id}

where "type" identifies the document type (document, schema, stylesheet, entity, xmlns, etc.), the optional "subtype" provides additional information about the document type (for example, stylesheet or schema language), and "object-id" is a unique identifier for the document.

The Director of Technical Operations at OASIS assigns document types, subtypes, and all unique identifiers.

Relevant ancillary documentation:

      None

Identifier uniqueness considerations:

Identifier uniqueness will be enforced by the Director of Technical Operations who assigns unique identifiers to all documents identified by URN.

Identifier persistence considerations:

OASIS is committed to maintaining the accessibility and persistence of all the resources that are assigned URNs.

Process of identifier assignment:

Assignment is limited to the owner and those authorities that are specifically designated by the owner. OASIS may assign portions of its namespace for assignment by other parties.

Process of identifier resolution:

The owner will distribute catalogs (OASIS TR9401 Catalogs) that map the assigned URNs to resource identifiers (e.g., URLs). A more interactive, online resolution system will also be deployed in the near future.

The owner will authorize additional resolution services as appropriate.

Rules for Lexical Equivalence:

URNs are lexically equivalent if they are lexically identical.

Conformance with URN Syntax:

No special considerations.

Validation mechanism:

None specified. The owner will publish OASIS TR9401 Catalogs. The presence of a URN in a catalog indicates that it is valid.

Scope:

      Global

3. Examples

The following examples are not guaranteed to be real. They are listed for pedagogical reasons only.

         urn:xmlorg:objects:schema:xmlschema:xcatalog
         urn:xmlorg:objects:dtd:xml:docbook:v4.1.2

4. Security Considerations

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

References

   [1] Goldfarb, C. F., "ISO (International Organization for
   
       Standardization) ISO 8879:1986(E) Information Processing -- Text
       and Office Systems -- Standard Generalized Markup Language
       (SGML)", 1986.
   
   [2] W3C, XML WG, "Extensible Markup Language (XML) 1.0", February
       1998, <http://www.w3.org/TR/REC-xml>.
   
   [3] W3C, Namespaces WG, "Namespaces in XML", January 1999,
       <http://www.w3.org/TR/REC-xml-names>.
   
   [4] OASIS, Entity Mgmt. TC, "Entity Management: OASIS Technical
       Resolution 9401:1997 (Amendment 2 to TR 9401)", January 1994,
       <http://www.oasis-open.org/html/a401.htm>.

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

   [6] Mealling, M. and R. Daniel, "URI Resolution Services Necessary
       for URN Resolution", RFC 2483, January 1999.

Authors' Addresses

   Karl Best
   OASIS, Inc.
   P.O. Box 455
   Billerica, MA  01821
   US
   
   EMail: karl.best@oasis-open.org
   
   Norman Walsh
   Sun Microsystems, Inc.
   One Network Drive
   MS UBUR02-201
   Burlington, MA  01803-0902
   US
   
   EMail: Norman.Walsh@East.Sun.COM

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Acknowledgement

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