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Versions: 02 03                                            Informational
IETF X.500 Schema Task Force                                  Tim Howes
INTERNET-DRAFT                                   University of Michigan
                                                             Ken Rossen
                                                        SHL Systemhouse
                                                      Srinivas Sataluri
                                                 AT&T Bell Laboratories
                                                            Russ Wright
                                           Lawrence Berkeley Laboratory
                                                             June 1995

         Procedures for Formalizing, Evolving, and Maintaining
                  the Internet X.500 Directory Schema
                Filename: draft-howes-x500-schema-03.txt

1.  Status of this Memo

The goal of the X.500 schema task force is to specify a set of pro-
cedures for reviewing, publicizing, and maintaining schema elements for
use in Internet applications using OSI Directory Services (X.500).

This document is an Internet-Draft.  Internet-Drafts are working docu-
ments of the Internet Engineering Task Force (IETF), its areas, and its
working groups.  Note that other groups may also distribute working
documents as Internet-Drafts.

Internet-Drafts are draft documents valid for a maximum of six months.
Internet-Drafts may be updated, replaced, or obsoleted by other docu-
ments at any time.  It is not appropriate to use Internet-Drafts as
reference material or to cite them other than as a ``working draft'' or
``work in progress.''

To learn the current status of any Internet-Draft, please check the
1id-abstracts.txt listing contained in the Internet-Drafts Shadow Direc-
tories on ds.internic.net, nic.nordu.net, ftp.isi.edu, or munnari.oz.au.

This Internet Draft expires December 10th, 1995.

Distribution of this memo is unlimited.  Comments and critiques of this
document, and new or updated schema definitions should be sent to x500-
schema@internic.net. Discussion about the Internet X.500 schema should
be carried out on the OSI-DS mailing list (osi-ds@cs.ucl.ac.uk).

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INTERNET-DRAFT                                                 June 1995

2.  Abstract

The IETF Schema Task Force proposes a set of procedures for reviewing,
publicizing, and maintaining schema elements for use in Internet appli-
cations using OSI Directory Services (X.500).

3.  Goals of the Internet Schema Procedures

The goals embodied in the procedures documented in this memo are four-

-    To identify a repository and appropriate useful formats for publi-
     cizing and distributing schema elements (object classes and attri-
     butes) to the Internet community.

-    To facilitate broad-based experimentation with new applications of
     X.500 by publicizing experimental schema elements.

-    To maintain a stable production schema for the Internet, including
     definitions both for common core of elements and application-
     specific subschemas

-    To avoid the overlap of schema element functionality where possi-

4.  Collection of Schema Elements

The Internet Directory Schema will evolve from the status quo as
represented in a forthcoming RFC documenting the current "baseline"
schema elements.  This baseline is expected to include both those object
classes and attributes with applicability to a wide variety of applica-
tions (the Core Schema), and certain elements arising from specific
applications (subschemas), some of which have been developed in other

In general, within the IETF, the X.500 schema group will concern itself
with evolving the Core schema while encouraging application-specific
subschemas to be developed by experts in the respective applications.

The schema group aims to align schema element definitions where
appropriate between the Internet schema and others within the Directory
community.  The publicizing of the Internet schema for external consump-
tion is one avenue for this, and consideration of schema elements docu-
mented in external sources is another.  Two such external sources are:

-    Standing documents of the North American Directory Forum

-    "F" series International Standard Profiles (ISPs) for use of the

IETF X.500 Schema Task Force  June 8, 1995                      [Page 2]

INTERNET-DRAFT                                                 June 1995

     Directory, developed by the Regional Workshops (AOW, EWOS, OIW) and
     published in ISO/IEC 10616.

5.  Publication of Schema Elements

The schema group recognizes short-term and long-term mechanisms for dis-
tributing definitions of Internet schema elements.  Both mechanisms
involve the use of the InterNIC Directory and Database Services as a

Short-term:Element definitions will be made available from the InterNIC
     via anonymous ftp (ftp://ds.internic.net/pub/src/x500/schema), via
     Gopher (gopher://ds.internic.net/1pub/src/x500/schema), and via the
     WWW (http://www.internic.net/pub/src/x500/schema).  The FTP archive
     will include ASN.1 definitions accompanied by text describing the
     semantics and use of each object class or attribute.  In addition,
     native formats for widely deployed X.500 implementations, particu-
     larly the QUIPU OID Table format, will be included where practical.

Long-term:When 1993 schema publication extensions to the Directory stan-
     dard are implemented widely in the Internet, these facilities will
     be used to distribute element definitions from the InterNIC DSA.
     If slow progress of deployment of schema publication extensions
     impedes this transition, consideration will be given to defining a
     1988-compatible directory schema for interim publication of schema
     elements.  In this case, a migration path to the 1993 format for
     schema publication operational attributes will be a priority.

In addition to the on-line publicizing and maintainance of schema ele-
ments, an informational RFC documenting the Internet schema will be
issued on a six-month update cycle.  This RFC will reflect the state of
the InterNIC schema repository at the time of publication.  The publica-
tion of the current Internet X.500 Schema in the RFC will indicate that
the published version is baselined and an on-line copy of the published
schema will be held on the InterNIC schema repository.  This version
will be available in the directory /pub/src/x500/schema.RFCxxxx on the
InterNIC machine(s) representing the baselined schema and the on-line
version will be in the directory /pub/src/x500/schema.RFC and will
represent the temporary evolving Internet X.500 schema.

Subschemas defined by other IETF WGs or external groups in the Directory
community should be submitted to the schema group for inclusion in the
on-line repository. However, these schema elements should be published
as RFCs using the regular RFC publication process.  Once such RFCs are
published, the schema group will accept these definitions as stable and
will not reproduce them in the regularly updated schema RFC.  Rather,
the schema RFC will contain pointers to documents produced by these
other groups which include the definitions.

IETF X.500 Schema Task Force  June 8, 1995                      [Page 3]

INTERNET-DRAFT                                                 June 1995

Wherever possible, external groups will be encouraged to submit docu-
ments containing their subschemas for publication as RFCs, in order to
allow interested parties to derive the Internet schema entirely from a
reading of the X.500 standard and selected RFCs.

6.  Procedures for Expanding the Internet Schema

The schema group will make available a template for submission of schema
elements for publication and consideration.  The template, to be defined
in a later edition of this document, will request a definition for the
syntax of the object class or attribute, sufficient details on the
schema elements including information about the submitter, date of sub-
mission, mailing-list where discussion is being held, status of the
schema segment, etc.  The template will be simple and will be processed
to produce an ASN.1 definition for the elements.

The completed template will be submitted by e-mail to the alias "x500-

Advancement of an experimental schema element to production status will
follow a period of experimentation and acceptance by the submitting WG,
and acceptance by the schema group. In particular, authors who submit
new schema elements (initially assigned experimental classification)
will be expected to make a good faith effort to progress the schema
using appropriate working-groups and other standards procedures towards
an Internet standard. Results from the period of experimentation, schema
group and WG consensus will be the basis for decisions on advancement of
candidate subschemas.

If it becomes apparent that there is no active experimentation with an
experimental status schema element and/or no efforts to progress them as
Internet standards, the schema elements may be retired after appropriate

In some circumstances, more than one subschema aimed at addressing the
requirements of the same application may be developed.  The schema group
will accept and publicize such overlapping subschemas as experimental.
However, only one competing schema proposal for an application will be
advanced by the schema group to production status.  As with decisions on
advancement to production status, results from the period of experimen-
tation, schema group and WG consensus will be the basis for identifying
the preferred among competing subschemas.

7.  Object Identifiers

The schema group does not aim to align all Internet schema elements
under a single OID arc.  It is appropriate for other groups already hav-
ing registered attributes and object classes under their own respective

IETF X.500 Schema Task Force  June 8, 1995                      [Page 4]

INTERNET-DRAFT                                                 June 1995

OID arcs to retain ownership of those definitions, and advancement of
schema elements from experimental to production status does not imply a
change of OID.  The schema group will advance the registration process
under an Internet arc for elements defined by external groups not wish-
ing to maintain OIDs in the long term.

8.  Security Considerations

Security considerations are not discussed in this memo.

9.  Authors' Addresses

Tim Howes
University of Michigan
ITD Research Systems
535 W William St.
Ann Arbor, MI 48103-4943, USA
(313) 747-4454

Ken Rossen
SHL Systemhouse
10 Williamsville Road
Hubbardston Center, MA
01452-1311 USA
+1 508 928 5368 (voice) 5399 (fax) 5116 (alt fax)

Srinivas R. Sataluri
AT&T Bell Laboratories
Room 1C-429, 101 Crawfords Corner Road
P.O. Box 3030
Holmdel, NJ 07733-3030, USA
(908) 949-7782

Russ Wright
Lawrence Berkeley Laboratory
1 Cyclotron Road
Mail Stop 50B-2258
Berkeley, CA 94720, USA
(510) 486-6965

            This Internet Draft expires December 10th, 1995.

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