URI - Definition

The Uniform Resource Identifier (URI) is the core identification scheme of the Web. URIs are specified as the means to provide identifiers to any concept.

Each schema defines identification of particular Web content types.

Each URI consists of: schema_name:schema_specific_form

URIs are governed by the following principles:

• URIs act as global, unambiguous identifiers for a resource.
• Each URI references a single resource.
• Different URIs cannot reference the same resource.
• URIs consistently refer to the same resource over time.

Uniform Resource Locators (URL) are types of URIs. An URL signifies that the resource referred to has a representation which can be acquired by an appropriate request over the Internet. For instance, http://www.wikipedia.org/ will bring the Wikipedia webpage.

There are many other URI schemes to represent content:

• ftp://ftp.is.co.za/rfc/rfc1808.txt
• gopher://spinaltap.micro.umn.edu/00/Weather/Los%20Angeles
• http://www.math.uio.no/faq/compression-faq/part1.html#sec1
• mailto:mduerst@ifi.unizh.ch
• news:comp.infosystems.www.servers.unix
• telnet://melvyl.ucop.edu
• urn:isbn:n-nn-nnnnnn-n
• fon:+49-838-0