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URN standardization work restarted by IETF

A new IETF working group, “Uniform Resource Names, Revised” (urnbis), has been formed, in order to update the key RFC’s describing the URN system (cf. our recent article “Persistent identifiers – an overview” by Juha Hakala).

Uniform Resource Names (URNs) are location-independent, persistent identifiers for Internet information resources.

The current RFCs defining URNs were published in 1997-2001. They rely on old (or even provisional) basic documents on the concepts of URI and URL. Moreover, at that time there was almost no URN implementation experience, so these RFCs are informational or experimental, not true Internet standards.

During the last decade, the URN system has gained significant popularity. Roughly 40 formal URN namespaces have been defined and registered with IANA and hundreds of millions of resources have been assigned URNs. This enables searching of and persistent linking to these documents, artifacts, and other objects. However, the URN system lacks a foundation that is consistent in terminology and formal description with present (Full) Internet Standards.

The core URN RFCs, RFC 2141 (URN Syntax) and RFC 3406 (Namespace Definition Mechanisms), are based on outdated framework documents and understanding of digital archiving. All references in RFC 2141 point to “work in progress” or documents that have been superseded at least once. Both these RFCs and several other URN-related RFCs such as URN namespace registrations for ISBN and ISSN will be updated by the new URN working group.

The lack of a standard definition of the ‘urn’ URI scheme fosters recurring discussions on what URNs are and IETF commitment to them. There is a need to clarify that URNs are specific URIs (namely those using the ‘urn’ URI scheme) and hence all general URI rules apply also to URNs.

There are at least two reasons to update some namespace registrations. In some cases the standards specifying the relevant underlying namespaces (such as International Standard Book Number (ISBN)) have been amended or expanded since the original specification of the related URN namespace. Moreover, the working groups update of the basic URN-related RFCs might introduce/identify inconsistencies or enable new functionality that can be utilized in a given namespace.

The working group is chartered to review and provide advice regarding selected URN namespace specifications including those for International Standard Book Number (ISBN. RFC 3187), National Bibliography Numbers (NBN. RFC 3188) and International Standard Serial Number (ISSN. RFC 3044).

For all document revisions, backward compatibility with previous URN-related RFCs will be retained. Existing URN implementations will remain compliant with the new RFCs, but it will be possible to add new functionality to them.

The working group will produce an updated set of URN-related RFCs, with drafts foreseen during the first half of 2011. All documents will be on the Standards-Track or BCP (Best Current Practice). These updates will provide a normative foundation for URNs and assure uniformity of the URN assignment and resolution concepts and procedures at the abstract level.

For additional information, please contact the working group chairs:
Andrew Newton ( and Alfred Hoenes (

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(This news item is based on information provided by Juha Hakala and text from the IETF Announcement list.)

More information about the author: traugottkoch

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