Recommendations for an X.500 Production Directory Service
RFC 1803

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Network Working Group                                          R. Wright
Request for Comments: 1803                  Lawrence Berkeley Laboratory
Category: Informational                                      A. Getchell
                                  Lawrence Livermore National Laboratory
                                                                T. Howes
                                                  University of Michigan
                                                             S. Sataluri
                                                  AT&T Bell Laboratories
                                                                  P. Yee
                                               NASA Ames Research Center
                                                                W. Yeong
                                 Performance Systems International, Inc.
                                                               June 1995

       Recommendations for an X.500 Production Directory Service

Status of this Memo

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

Abstract

   This document contains a set of basic recommendations for a country-
   level X.500 DSA.  These recommendations can only be considered a
   starting point in the quest to create a global production quality
   X.500 infrastructure.  For there to be a true "production quality"
   X.500 infrastructure more work must be done, including a transition
   from the 1988 X.500 (plus some Internet extensions) to the 1993 X.500
   standard (including the '93 replication and knowledge model).  This
   document does not discuss this transition.

1.  Introduction

   The ISO/CCITT X.500 Directory standard enables the creation of a
   single world-wide Directory that contains information about various
   types of information, including people. In the United States, in mid
   1989 NYSERNet (the project was later taken over by Performance
   Systems International - PSI) started a White-pages Pilot Project
   (WPP).  Several organizations in the US joined this project.  The PSI
   WPP provided the c=US root level master Directory System Agent (DSA)
   where organizations that joined the pilot were connected.  In
   November 1990, the PARADISE project was started in Europe to provide
   an international directory service across Europe with international
   connectivity to the rest of the world.  The PARADISE project also
   operated the "root of the world" DSA that connected each of the

Wright, et al                Informational                      [Page 1]
RFC 1803           X.500 Production Directory Service          June 1995

   national pilots into a single world-wide Directory Information Tree
   (DIT), enabling information about people all over the world to be
   obtainable using an Internet DUA (Directory User Agent).

   Much of the criticism of X.500 stems from the lack of a production
   quality infrastructure.  Although there are already well over 500
   organizations and 1,000,000 entries in the the X.500 directory, some
   portions of the directory are still considered a "pilot project".
   Poor availability of portions of the directory and inconsistent
   quality of information are two problems that have not been adequately
   addressed in a number of the X.500 "pilot projects".  One of the
   reasons for this has been a lack of formal service objectives for
   running an X.500 service, and recommendations for achieving them.

   In X.500, the country-level DSAs form the access path for the rest of
   the world to access directory entries associated with that country's
   organizations.  Thus, the availability and performance of the
   country-level DSAs give an upper bound to the quality of service of
   the whole country's part of the Directory.

2. Recommendations for the country-level Master DSA

   We will split the recommendations into three categories:  Operational
   recommendations for the organization running the master DSA (service
   provider), DSA recommendations and personnel recommendations.

2a. Operational recommendations for the country-level master and shadow
    DSAs

   In general, the country-level data should be available for querying
   100% of the time.  Availability for updating is also important, but
   may be slightly reduced in practice, given X.500's single master
   scheme.

   *  The master DSA should be available at least 95% of the time.  This
   means that the DSA must be monitored and supported over the weekend.

   * The Master DSA and its shadows should be positioned to minimize the
   possibility of single points of failure.

   * The master and its shadow DSAs should be disbursed across the
   national network infrastructure in order to distribute the load
   across the network, and to get the information closer to the
   requesters.  This distribution should also minimize the possibility