W3C | Member Guide

URIs for W3C Namespaces

This is obsolete in favor of a new version of this document circa 2005/2006.

This is a policy and administrative issue for W3C. This policy may be elaborated or extended in the future.

Exceptions to this policy MAY be authorized by the Director.

1. Syntax of Namespace URIs

Namespace URIs in Recommendation Track documents shall start with "http://www.w3.org/" followed by four decimal digits corresponding to the common era year of issue. A group MAY request a specific path component for the rest of the URI, but the Webmaster has final authority over it.

Groups SHOULD use namespace URIs that have the characteristics of uniqueness.

1.1 Rationale for this Syntax

The reason for this is that the W3C support staff must ensure very high level of persistence for these URIs, in terms of the non-reuse and the availability of any online materials (schemata etc).

The "www.w3.org" is used instead of "w3.org" (an internal decision made for the entire site many months ago) because

The form "http://www.w3.org/activity/date/foo" cannot be readily implemented due to the diversity of policies governing each subtree of the W3C site. These policies vary in order to support the diversity of work styles and tools used across the Consortium. Therefore no consistent commitment to persistence can be made in such a sweeping way. Group participants should bear in mind that the W3C Team will be maintaining this Web space long after the groups have become more interested in other topics or have been closed.

2. Allocation and Approval of Namespace URIs

The W3C Webmaster allocates all namespace URIs. Director approval of a namespace URI is NOT REQUIRED when it has the form http://www.w3.org/YYYY/MM/ssss, where ssss is a short string not causing confusion, alarm, or embarrassment. For specifications that are likely to be widely used, the Director MAY authorize a (shorter) namespace URI of the form http://www.w3.org/YYYY/ssss.

For Recommendation Track documents, the persistence policy for the namespace MUST use the template shown below.

W3C provides the service of allocating and maintaining persistent URIs so that those URIs remain stable during discussions. Allocation does not imply any endorsement by W3C of the related specifications. This persistence policy only applies to URIs of the above form, and does not apply to other URIs within w3.org (e.g., those for lists.w3.org).

2.1 Member and Team Submissions

Some Member and Team Submissions are designed to seed work on the Recommendation Track; others simply provide information or serve other purposes.

In all Member and Team Submissions:

  1. Namespace URIs MUST be dereferenceable, and
  2. Namespace Documents must describe the relationship between the defining specification and the Namespace URI

When a Submission is designed to seed work on the Recommendation Track:

  1. Namespace URIs SHOULD follow the conventions for Recommendation Track documents in order to ease the later transition to the Rec Track. If it does not, the URI publisher MUST have clear persistence policy (similar to W3C's, i.e., that the URI publisher will make every effort to service requests for the Namespace Document).

3. Relationship between Defining Specification and Namespace URI

It is important to specify clearly the relationship between the Namespace URI and the specification that defines it. Groups SHOULD explain that relationship in the defining specification and/or schema. To this end, Groups SHOULD use this template, deleting [..] as appropriate.

This namespace name (URI) will only be used to refer to this version of this specification: different URIs will be used for any and all new versions of the specification [except as follows].

  1. [This namespace name may be reused in any update of the specification which is made for the purpose of clarification or bug fixes. These changes will be minor in that they do not (a) change the meaning or validity of existing documents written using the namespace, or (b) affect the operation of existing software written to process such documents.]
  2. [Warning: Until the specification reaches W3C Candidate Recommendation (CR) status, this namespace name may be reused by any update in such a way as to cause documents written using the namespace to become invalid or to change in meaning.]
  3. [Warning: Until the specification reaches W3C CR status, this namespace name may be reused by any update in such a way as to affect the operation of existing software written to process documents written according to this specification.]

Note: To give a specification the necessary stability, provisions two and three of the template MUST NOT be used in a Proposed [Edited] Recommendation or Recommendation.

4. Namespace Document

A Namespace Document describes the namespace, providing directly or by reference information for human and also, ideally, machine consumption. A Namespace Document is available for retrieval using a corresponding Namespace URI.

When a Namespace URI appears in a Recommendation Track document, the responsible group MUST publish a corresponding Namespace Document. In other contexts as well, groups SHOULD publish Namespace Documents. RDFS and/or OWL are used for RDF namespaces.

5. About This Document

This policy was announced to the Chairs on 26 October 1999 (announcement). TimBL writes:

As there has been much lengthy discussion of the philosophy behind this, and it involved much arbitrariness in the decision, I am making this policy clear now so as to let us all get down to the rest of our business as we have enough other stuff to discuss.

Discussion of this policy is appropriate in the uri mailing list and various other lists.

5.1 Background

5.2 Acknowledgments

Thank you Joseph Reagle for providing input for the polices and pointing out that a good policy should make namespace allocation automatic.

Tim Berners-Lee, W3C Director. Send comments to w3t-comm@w3.org.

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