The COSINE and Internet X.500 Schema
RFC 1274

Document Type RFC - Proposed Standard (November 1991; No errata)
Obsoleted by RFC 4524
Last updated 2013-03-02
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Network Working Group                                          P. Barker
Request for Comments: 1274                                      S. Kille
                                               University College London
                                                           November 1991

                  The COSINE and Internet X.500 Schema

Status of this Memo

   This RFC specifies an IAB standards track protocol for the Internet
   community, and requests discussion and suggestions for improvements.
   Please refer to the current edition of the "IAB Official Protocol
   Standards" for the standardization state and status of this protocol.
   Distribution of this memo is unlimited.


   This document suggests an X.500 Directory Schema, or Naming
   Architecture, for use in the COSINE and Internet X.500 pilots.  The
   schema is independent of any specific implementation.  As well as
   indicating support for the standard object classes and attributes, a
   large number of generally useful object classes and attributes are
   also defined.  An appendix to this document includes a machine
   processable version of the schema.

   This document also proposes a mechanism for allowing the schema to
   evolve in line with emerging requirements.  Proformas to support this
   process are included.

   Corrections and additions to the schema should be sent to na- list, as described within.

1.  Introduction

   Directory Services are a fundamental requirement of both human and
   computer communications' systems.  Human users need to be able to
   look up various details about other people: for example, telephone
   numbers, facsimile numbers and paper mail addresses.  Computing
   systems also need Directory Services for several purposes: for
   example, to support address look-ups for a variety of services, and
   to support user-friendly naming and distribution lists in electronic
   mail systems.

   Directory Services have recently been standardised and published as
   the 1988 CCITT X.500 / ISO IS9594 recommendations [1].  The standard
   provides a good basis for the provision of real services, and a
   considerable amount of Directory Service piloting activity is

Barker & Kille                                                  [Page 1]
RFC 1274            COSINE and Internet X.500 Schema       November 1991

   currently underway.  In the U.S., the PSI White Pages Pilot [4] has
   stimulated use of X.500 on the Internet.  In Britain, the U.K.
   Academic Community Directory Pilot [5] is similarly promoting use of

2.  Motivation and aims of this document

   In a number of areas the X.500 standard only provides a basis for
   services.  One such area is the Directory's Schema or Naming
   Architecture.  The standard defines a number of useful object
   classes, in X.521, and attribute types, in X.520.  These are intended
   to be generally useful across a range of directory applications.
   However, while these standard definitions are a useful starting
   point, they are insufficient as a basis for a large scale pilot

   While it is possible for directory administrators to define their own
   sets of additional attribute types and object classes, this is
   undesirable for some common attributes and objects.  The same objects
   and attribute types would be privately defined many times over.  This
   would result in the directory's generality being diminished as remote
   systems would be unable to determine the semantics of these privately
   defined data types.

   A number of useful additions to the standard definitions were made in
   this note's forerunner, "The THORN and RARE Naming Architecture" [2].
   These have been heavily used in early X.500 piloting activities.
   Furthermore, both the THORN and Quipu X.500 implementations have made
   use of these definitions.

   Since the afore-mentioned note was issued, a number of further
   requirements have come to light as the volume and variety of piloting
   activity has increased.  Yet further requirements seem likely as the
   scale of X.500 pilot services increases.  Thus, it is argued that it
   is not sufficient to merely reissue an updated version of the
   original note. The schema is a "living document" that needs
   procedures for:

      - Allowing submission of requests for new attributes and
        object classes to be added into the schema;

      - Allowing groups of object classes and attribute types
        defined elsewhere to be integrated into the schema.

      - Checking for the redundancy of any previously defined
        attribute types and object classes.

   This document attempts to establish procedures to allow for the

Barker & Kille                                                  [Page 2]
RFC 1274            COSINE and Internet X.500 Schema       November 1991

   continual updating of the schema.  Two proformas are set out for this
   purpose.  In addition, descriptive detail is provided for the
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