W3C Architecture Domain

Naming and Addressing: URIs, URLs, ...

Links · About URIs · History

This is an overview of W3C materials related to Addressing. The URI Activity Statement explains W3C's work on this topic in more detail.
Standards Track Specifications
Uniform Resource Identifier (URI): Generic Syntax, Internationalized Resource Identifiers (IRIs), BCP for scheme registration process, guidelines for new schemes, IANA's list of URI schemes
Current W3C work on URIs
URI Activity Statement, URI Interest Group
Related W3C work
Technical Architecture Group (TAG), Internationalization, Semantic Web, RDF, Extensible Markup Language (XML)
Related IETF work, supported by W3C

Work on RFC 2396 update (to IETF Standard)

Personal Perspectives
Community Discussion
uri@w3.org, www-talk@w3.org, UriSchemes topic in the ESW Wiki

Learning About URIs

The Web is an information space. Human beings have a lot of mental machinery for manipulating, imagining, and finding their way in spaces. URIs are the points in that space.

Unlike web data formats, where HTML is an important one, but not the only one, and web protocols, where HTTP has a similar status, there is only one Web naming/addressing technology: URIs.

Uniform Resource Identifiers (URIs, aka URLs) are short strings that identify resources in the web: documents, images, downloadable files, services, electronic mailboxes, and other resources. They make resources available under a variety of naming schemes and access methods such as HTTP, FTP, and Internet mail addressable in the same simple way. They reduce the tedium of "log in to this server, then issue this magic command ..." down to a single click.

It is an extensible technology: there are a number of existing addressing schemes, and more may be incorporated over time.

Timeline: News, Events, Publications, and History

This is a publication history, or bibliography collected from IETF documents and W3C Technical Reports as well as a record of events.

Jan 2005
Uniform Resource Identifier (URI): Generic Syntax [RFC3986]
Jan 2005
Internationalized Resource Identifiers (IRIs)
March 2003
Uniform Resource Identifiers (uribof) Bof at IETF 56 in San Francisco
March 2001
Future of URI (FURI) BOF at IETF 50, Minneapolis
Nov 1999
Guidelines for new URL Schemes, November 1999 RFC2718
Nov 1999
Registration Procedures for URL Scheme Names R. Petke, (RFC 2717)
Dec 1998
Hypertext Style: Cool URIs don't change section added to Style Guide for online hypertext
August 1998
Uniform Resource Identifiers (URI): Generic Syntax
(RFC 2396) T. Berners-Lee, R. Fielding, L. Masinter
May 1997
URN Syntax

RFC 2141 R. Moats

Apr 1997
38th IETF: URN WG meeting (research notes)
Dec 1996
San Jose IETF -- URL BOF
Nov 1996
W3C and Digital Libraries, James S. Miller, D-Lib Magazine
Spring 1996
2nd issue of W3J, Key Specifications of the World Wide Web includes URI specs.
July 1995
IETF URI Working Group is closed.
June 1995
RFC 1808 released as Proposed Standard

Relative Uniform Resource Locators R. Fielding


... When embedded within a base document, a URL in its absolute form may contain a great deal of information which is already known from the context of that base document's retrieval, including the scheme, network location, and parts of the url-path. In situations where the base URL is well-defined and known to the parser (human or machine), it is useful to be able to embed URL references which inherit that context rather than re-specifying it in every instance.

This one is both authoritative (i.e. it's been through the IETF proposed standard process) and accurate on the matter of the syntax of URLs. Its grammar is complete and consistent, and there are several clarifying examples.

On the other hand, it does not discuss any of the actual URL schemes (such as HTTP, FTP, ...)

December 1994
(RFC 1738) released as Proposed Standard:

Uniform Resource Locators (URL) T. Berners-Lee, L. Masinter, M. McCahill


This document specifies a Uniform Resource Locator (URL), the syntax and semantics of formalized information for location and access of resources via the Internet.

This one is ratified as an IETF proposed standard, and it discusses each of the URL schemes (known at that time), but its grammar has some mistakes, and it doesn't cover several aspects of URL syntax, such as relative URLs and fragment identifiers

December 1994
RFC 1737, Informational

Functional Requirements for Uniform Resource Names , K. Sollins, L. Masinter


This document specifies a minimum set of requirements for a kind of Internet resource identifier known as Uniform Resource Names (URNs). ...
June 1994
RFC 1630, Informational, is released:

Universal Resource Identifiers in WWW: A Unifying Syntax for the Expression of Names and Addresses of Objects on the Network as used in the World-Wide Web T. Berners-Lee.

This documents the designer's intent, before it was revised by the standards process. It was written by Tim Berners-Lee, but has only informational status in the IETF. It discusses all aspects of URLs (relative, etc.) though it has some mistakes in the grammar etc.
March 94
IETF URI working group is formed
Tim Berners-Lee's original writings on Document Naming, part of Design Issues for the Web

See also:

Dan Connolly
$Revision: 1.58 $ of $Date: 2006/02/27 15:15:52 $
Created 1993 by TimBL

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