Uniform Resource Name

From Well Designed Urls WiKi

A Uniform Resource Name (URN) is a Uniform Resource Identifier (URI) that uses the urn Scheme, and does not imply availability of the identified Resource. Both URNs (names) and URLs (locators) are URIs, and a particular URI may be a name and a locator at the same time.

The Functional Requirements for Uniform Resource Names are described in RFC 1737. The URNs are part of a larger Internet information architecture which is composed of URNs, Uniform Resource Characteristics (URCs), and Uniform Resource Locators (URLs). Each plays a specific role:

• URNs are used for identification,
  • URCs for including meta-information.
    • URLs for locating or finding resources.

RFC 2141 says:

Uniform Resource Names (URNs) are intended to serve as persistent, location-independent resource identifiers and are designed to make it easy to map other namespaces (that share the properties of URNs) into URN-space. Therefore, the URN syntax provides a means to encode character data in a form that can be sent in existing protocols, transcribed on most keyboards, etc.

Read more about URNs on Wikipedia.