URN

Draft

Definition

• Uniform Resource Names (URNs) are intended to serve as persistent, location-independent, universal resource identifiers (URIs).

• URNs have been formalized in the RFC 2141 and are also addressed in the RFC 3986 URI Syntax specification.

Examples

Today, most popular URNs are probably DOIs (stable URIs used by publishers of scientific articles).

Here are a few URN examples (frankly, I don't understand why the "urn" is needed here - Daniel K. Schneider):

urn:issn:1082-9873
urn:doi:10.1000/1
urn:oasis:names:specification:docbook:dtd:xml:4.1.2

URNs vs. URLs

As everybody knows, URLs change all the time. Web pages move and CMS/Databases are reorganized. Some of the information won't be dead but it will be moved to other places. If information is important (e.g. identification of a scientific article, URN resolvers may be able to find it again).

Example of a URI in both URL and URI form (from RFC 3986):

http://example.com:8042/over/there?name=ferret#nose
     \_/   \______________/\_________/ \_________/ \__/
      |           |            |            |        |
   scheme     authority       path        query   fragment
      |   _____________________|__
     / \ /                        \
     urn:example:animal:ferret:nose

Links

• DOI HomePage

References

Standards

• RFC2141 URN Syntax

Related standards

• RFC 3986 URI Syntax
• RFC 1738 - URL Syntax
• RFC 2288 - Using Existing Bibliographic Identifiers as Uniform Resource Names

Introductory articles

• Dan Connolly (2005). Untangle URIs, URLs, and URNs, Naming and the problem of persistence, IBM developerWorks article, HTML