A URN Namespace for XML.org
A URN namespace for naming persistent resources in the XML.org repository.
Best, K. and N. Walsh, "A URN Namespace for XML.org", RFC 3120, DOI 10.17487/RFC3120, June 2001, <https://www.rfc-editor.org/info/rfc3120>.
@misc{rfc3120,
series = {Request for Comments},
number = 3120,
howpublished = {RFC 3120},
publisher = {RFC Editor},
doi = {10.17487/RFC3120},
url = {https://www.rfc-editor.org/info/rfc3120},
author = {K. Best and N. Walsh},
title = {{A URN Namespace for XML.org}},
pagetotal = 5,
year = 2001,
month = jun,
} RFC text
Contents
Network Working Group K. Best
Request for Comments: 3120 OASIS, Inc.
Category: Informational 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 (C) 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
Full Copyright Statement
Copyright (C) The Internet Society (2001). All Rights Reserved.
This document and translations of it may be copied and furnished to
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Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
ISO Plain Language
On this page
§1Why XML.org Resources Need URNs
The XML.org Registry is a public repository where XML schemas, DTDs, stylesheets, and other documents can be shared and retrieved. These resources need unique identifiers. XML.org wants to assign Uniform Resource Names (URNs) that give resources unique, permanent names independent of their locations.
RFC 3120 specifies a formal URN namespace with the identifier xmlorg. The memo names OASIS as the registrant and says OASIS is committed to maintaining the accessibility and persistence of resources assigned these URNs.
A resource needs a name that identifies it even if its location changes. RFC 3120 defines a URN namespace for resources stored in the XML.org repository.
§2The Structure of an xmlorg URN
The namespace has one top-level branch, objects. Its names follow this pattern: urn:xmlorg:objects:{type}{:subtype}?:{object-id}. The type identifies the document type, such as a schema, stylesheet, entity, or namespace. The optional subtype adds information about the type, such as a schema or stylesheet language.
The object-id uniquely identifies the document. The Director of Technical Operations at OASIS assigns document types, subtypes, and identifiers. The RFC gives examples such as urn:xmlorg:objects:schema:xmlschema:xcatalog and urn:xmlorg:objects:dtd:xml:docbook:v4.1.2, and says the examples are not guaranteed to be real.
An xmlorg URN includes the resource type and a unique ID. An optional part gives more detail about the type, such as which schema language it uses.
§3Finding a Resource from Its URN
OASIS says it will distribute TR9401 catalogs that map assigned URNs to resource identifiers such as URLs. It may authorize additional resolution services, and at the time of the RFC a more interactive online service was planned. The presence of a URN in a catalog indicates that it is valid; the RFC specifies no separate validation mechanism.
Two URNs are lexically equivalent only when they are lexically identical. The namespace specification adds no special comparison rules. The security section says there are no additional security considerations beyond those normally associated with using and resolving URNs.
A catalog maps a URN to a resource identifier, such as a URL. The RFC says two names match only when they are written identically.