RFC 1803 (rfc1803) - Page 2 of 8

Recommendations for an X

Alternative Format: Original Text Document


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
   of a single point of failure, increasing availability.






Wright, et al                Informational

Web Standards & Support: