World Wide Web Consortium Supports the IETF URI Standard and IRI Proposed Standard

Author(s) and publish date


URI Specification Updated, IRIs Allow Internationalized Web Addressing -- 26 January 2005 -- The World Wide Web Consortium (W3C) announces its support for two newly issued publications that are critical to increasing the international reach of the World Wide Web. These publications, coordinated through both the IETF and W3C, are RFC 3986, STD 66 Uniform Resource Identifier (URI): Generic Syntax and RFC 3987 Internationalized Resource Identifiers (IRIs), respectively an Internet Engineering Task Force (IETF) Internet Standard and Proposed Standard.

URIs and IRIs Are the Glue That Holds the Web Together

The World Wide Web is defined as the universal, all-encompassing space containing all Internet - and other - resources referenced by Uniform Resource Identifiers (URIs, sometimes commonly called "URLs").

In Tim Berners Lee's original proposal, and in the initial Web implementation, the Web consisted of relatively few technologies, including the Hypertext Transfer Protocol (HTTP) and the HyperText Markup Language (HTML). Yet perhaps more fundamental than either HTTP or HTML are URIs, which are simple text strings that refer to Internet resources -- documents, resources, people, and indirectly to anything. URIs are the glue that binds the Web together. IRIs extend and strengthen the glue, by allowing people to identify Web resources in their own language.

The IETF Internet Standards Process has produced thousands of publications, including approximately 60 Internet Standards. The URI specification is joining this small group. An Internet Standard (or "Standard") has a high degree of technical maturity and is believed to provide significant benefit to the Internet community. The newer of the two documents, the IRI specification, has been published as a Proposed Standard.

Fundamental Component of the Web Updated

Uniform Resource Identifier (URI): Generic Syntax was written by Tim Berners-Lee (Director, W3C), Roy Fielding (Day Software) and Larry Masinter (Adobe Systems) with involvement of the W3C Technical Architecture Group (TAG). The Standard describes the design, syntax, and resolution of URIs as well as security considerations and normalization and comparison (determining if two URIs are equivalent).

This new Standard replaces the URI specification released in 1998. Among several technical changes, the host component of a URI is now enabled for internationalized domain names. Other technical changes include a rule for absolute URIs with optional fragments, a rewritten section 6 "Normalization and Comparison" by Tim Bray and the W3C TAG, simplified grammar, clarifications for ambiguities, and revisions to the reserved set of characters.

IRIs Allow Internationalized Web Addressing

The Internationalized Resource Identifiers (IRIs) Proposed Standard was developed in part by the W3C Internationalization Working Group, and was written by Martin Dürst (W3C) and Michel Suignard (Microsoft Corporation).

With few exceptions, the natural scripts of the world's languages use characters other than A-Z. By expanding allowed characters from a subset of US-ASCII to the Universal Character Set (Unicode/ISO 10646), IRIs allow content developers and users to identify resources in their own languages. In addition, many W3C specifications - such as XML, RDF, XHTML and SVG - needed a definitive reference for identifiers that support international characters. The IRI specification provides that critical reference.

According to the IRI specification, every URI is already an IRI. As a result, URI users do not need to do anything differently in order to find what they need on the Web. The specification also discusses how to convert an IRI to a URI for resolution on existing systems, the special case of bidirectional IRIs, equivalence between IRIs, IRI use in different situations, security considerations and informative guidelines.

IETF and W3C Cooperation Produces Strong Results

These IETF documents are good examples of the longstanding cooperation between IETF and W3C.

Along with the HTTP specification, the URI specifications pre-date W3C, and are among the earliest documented Web work. As these specifications continue to be useful to many IETF efforts, their standardization continued within the IETF. The W3C URI Activity hosts discussion forums and provides editing resources and coordinates with other W3C Activities on Web technologies.

About the World Wide Web Consortium [W3C]

The W3C was created to lead the Web to its full potential by developing common protocols that promote its evolution and ensure its interoperability. It is an international industry consortium jointly run by the MIT Computer Science and Artificial Intelligence Laboratory (MIT CSAIL) in the USA, the European Research Consortium for Informatics and Mathematics (ERCIM) headquartered in France and Keio University in Japan. Services provided by the Consortium include: a repository of information about the World Wide Web for developers and users, and various prototype and sample applications to demonstrate use of new technology. More than 350 organizations are Members of W3C. For more information see


Contact Americas and Australia --
Janet Daly, <>, +1.617.253.5884 or +1.617.253.2613
Contact Europe, Africa and Middle-East --
Marie-Claire Forgue, <>, +33.492.38.75.94
Contact Asia --
Yasuyuki Hirakawa, <>, +81.466.49.11.70

Related RSS feed