Functional Requirements for Uniform Resource Names
RFC 1737

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 00

Network Working Group                                         K. Sollins
Request for Comments: 1737                                       MIT/LCS
Category: Informational                                      L. Masinter
                                                       Xerox Corporation
                                                           December 1994

           Functional Requirements for Uniform Resource Names

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

1.  Introduction

   This document specifies a minimum set of requirements for a kind of
   Internet resource identifier known as Uniform Resource Names (URNs).
   URNs fit within a larger Internet information architecture, which in
   turn is composed of, additionally, Uniform Resource Characteristics
   (URCs), and Uniform Resource Locators (URLs).  URNs are used for
   identification, URCs for including meta-information, and URLs for
   locating or finding resources.  It is provided as a basis for
   evaluating standards for URNs.  The discussions of this work have
   occurred on the mailing list uri@bunyip.com and at the URI Working
   Group sessions of the IETF.

   The requirements described here are not necessarily exhaustive; for
   example, there are several issues dealing with support for
   replication of resources and with security that have been discussed;
   however, the problems are not well enough understood at this time to
   include specific requirements in those areas here.

   Within the general area of distributed object systems design, there
   are many concepts and designs that are discussed under the general
   topic of "naming". The URN requirements here are for a facility that
   addresses a different (and, in general, more stringent) set of needs
   than are frequently the domain of general object naming.

   The requirements for Uniform Resource Names fit within the overall
   architecture of Uniform Resource Identification.  In order to build
   applications in the most general case, the user must be able to
   discover and identify the information, objects, or what we will call
   in this architecture resources, on which the application is to
   operate.  Beyond this statement, the URI architecture does not define
   "resource."  As the network and interconnectivity grow, the ability
   to make use of remote, perhaps independently managed, resources will

Sollins & Masinter                                              [Page 1]
RFC 1737        Requirements for Uniform Resource Names    December 1994

   become more and more important.  This activity of discovering and
   utilizing resources can be broken down into those activities where
   one of the primary constraints is human utility and facility and
   those in which human involvement is small or nonexistent.  Human
   naming must have such characteristics as being both mnemonic and
   short.  Humans, in contrast with computers, are good at heuristic
   disambiguation and wide variability in structure.  In order for
   computer and network based systems to support global naming and
   access to resources that have perhaps an indeterminate lifetime, the
   flexibility and attendant unreliability of human-friendly names
   should be translated into a naming infrastructure more appropriate
   for the underlying support system.  It is this underlying support
   system that the Internet Information Infrastructure Architecture
   (IIIA) is addressing.

   Within the IIIA, several sorts of information about resources are
   specified and divided among different sorts of structures, along
   functional lines.  In order to access information, one must be able
   to discover or identify the particular information desired,
   determined both how and where it might be used or accessed.  The
   partitioning of the functionality in this architecture is into
   uniform resource names (URN), uniform resource characteristics (URC),
   and uniform resource locators (URL).  A URN identifies a resource or
   unit of information.  It may identify, for example, intellectual
   content, a particular presentation of intellectual content, or
   whatever a name assignment authority determines is a distinctly
   namable entity.  A URL identifies the location or a container for an
   instance of a resource identified by a URN.  The resource identified
   by a URN may reside in one or more locations at any given time, may
   move, or may not be available at all.  Of course, not all resources
   will move during their lifetimes, and not all resources, although
   identifiable and identified by a URN will be instantiated at any
   given time.  As such a URL is identifying a place where a resource
   may reside, or a container, as distinct from the resource itself
   identified by the URN.  A URC is a set of meta-level information
   about a resource.  Some examples of such meta-information are: owner,