RFC 2396 (rfc2396) - Page 2 of 40
Uniform Resource Identifiers (URI): Generic Syntax
Alternative Format: Original Text Document
RFC 2396 URI Generic Syntax August 1998
1. Introduction
Uniform Resource Identifiers (URI) provide a simple and extensible
means for identifying a resource. This specification of URI syntax
and semantics is derived from concepts introduced by the World Wide
Web global information initiative, whose use of such objects dates
from 1990 and is described in "Universal Resource Identifiers in WWW"
[RFC 1630]. The specification of URI is designed to meet the
recommendations laid out in "Functional Recommendations for Internet
Resource Locators" [RFC 1736] and "Functional Requirements for Uniform
Resource Names" [RFC 1737].
This document updates and merges "Uniform Resource Locators"
[RFC 1738] and "Relative Uniform Resource Locators" [RFC 1808] in order
to define a single, generic syntax for all URI. It excludes those
portions of RFC 1738 that defined the specific syntax of individual
URL schemes; those portions will be updated as separate documents, as
will the process for registration of new URI schemes. This document
does not discuss the issues and recommendation for dealing with
characters outside of the US-ASCII character set [ASCII]; those
recommendations are discussed in a separate document.
All significant changes from the prior RFCs are noted in Appendix G.
1.1 Overview of URI
URI are characterized by the following definitions:
Uniform
Uniformity provides several benefits: it allows different types
of resource identifiers to be used in the same context, even
when the mechanisms used to access those resources may differ;
it allows uniform semantic interpretation of common syntactic
conventions across different types of resource identifiers; it
allows introduction of new types of resource identifiers
without interfering with the way that existing identifiers are
used; and, it allows the identifiers to be reused in many
different contexts, thus permitting new applications or
protocols to leverage a pre-existing, large, and widely-used
set of resource identifiers.
Resource
A resource can be anything that has identity. Familiar
examples include an electronic document, an image, a service
(e.g., "today's weather report for Los Angeles"), and a
collection of other resources. Not all resources are network
"retrievable"; e.g., human beings, corporations, and bound
books in a library can also be considered resources.
Berners-Lee, et. al. Standards Track