Representing Tables and Subtrees in the X.500 Directory
RFC 1837

Document Type RFC - Experimental (August 1995; No errata)
Obsoleted by RFC 2293
Last updated 2013-03-02
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Network Working Group                                           S. Kille
Request for Comments: 1837                              ISODE Consortium
Category: Experimental                                       August 1995

        Representing Tables and Subtrees in the X.500 Directory

Status of this Memo

   This memo defines an Experimental Protocol for the Internet
   community.  This memo does not specify an Internet standard of any
   kind.  Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

Abstract

   This document defines techniques for representing two types of
   information mapping in the OSI Directory [1].

   1.  Mapping from a key to a value (or set of values), as might be
       done in a table lookup.

   2.  Mapping from a distinguished name to an associated value (or
       values), where the values are not defined by the owner of the
       entry.  This is achieved by use of a directory subtree.

   These techniques were developed for supporting MHS use of Directory
   [2], but are specified separately as they have more general
   applicability.

1.  Representing Flat Tables

   Before considering specific function, a general purpose technique for
   representing tables in the directory is introduced.  The schema for
   this is given in Figure 1.

   A table can be considered as an unordered set of key to (single or
   multiple) value mappings, where the key cannot be represented as a
   global name.  There are four reasons why this may occur:

   1.  The object does not have a natural global name.

   2.  The object can only be named effectively in the context of being
       a key to a binding.  In this case, the object will be given a
       natural global name by the table.

Kille                         Experimental                      [Page 1]
RFC 1837                 Representing Subtrees               August 1995

   3.  The object has a global name, and the table is being used to
       associate parameters with this object, in cases where they cannot
       be placed in the objects global entry.  Reasons why they might
       not be so placed include:

        o  The object does not have a directory entry

        o  There is no authority to place the parameters in the global
           entry

        o  The parameters are not global --- they only make sense in the
           context of the table.

   4.  It is desirable to group information together as a performance
       optimisation, so that the block of information may be widely
       replicated.

   A table is represented as a single level subtree.  The root of the
   subtree is an entry of object class Table.  This is named with a
   common name descriptive of the table.  The table will be located
   somewhere appropriate to its function.  If a table is private to an
   MTA, it will be below the MTA's entry.  If it is shared by MTA's in
   an organisation, it will be located under the organisation.

   The generic table entry contains only a description.  All instances
   will be subclassed, and the subclass will define the naming
   attribute.  Two subclasses are defined:

-----------------------------------------------------------------------
table OBJECT-CLASS ::= {
    SUBCLASS OF {top}
    MUST CONTAIN {commonName}
    MAY CONTAIN {manager}
    ID oc-table}

tableEntry OBJECT-CLASS ::= {
    SUBCLASS OF {top}
    MAY CONTAIN {description}                                       10
    ID oc-table-entry}

textTableEntry OBJECT-CLASS ::= {
    SUBCLASS OF {tableEntry}
    MUST CONTAIN {textTableKey}
    MAY CONTAIN {textTableValue}
    ID oc-text-table-entry}

textTableKey ATTRIBUTE ::= {

Kille                         Experimental                      [Page 2]
RFC 1837                 Representing Subtrees               August 1995

    SUBTYPE OF name                                                 20
    WITH SYNTAX DirectoryString {ub-name}
    ID at-text-table-key}

textTableValue ATTRIBUTE ::= {
    SUBTYPE OF name
    WITH SYNTAX  DirectoryString {ub-description}
    ID at-text-table-value}

distinguishedNameTableEntry OBJECT-CLASS ::= {
    SUBCLASS OF {tableEntry}                                        30
    MUST CONTAIN {distinguishedNameTableKey}
    ID oc-distinguished-name-table-entry}

distinguishedNameTableKey ATTRIBUTE ::= {
    SUBTYPE OF distinguishedName
    ID at-distinguished-name-table-key}

                     Figure 1:  Representing Tables

1.  TextEntry, which define table entries with text keys, which may
    have single or multiple values of any type.  An attribute is
    defined to allow a text value, to support the frequent text key to
    text value mapping.  Additional values may be defined.

2.  DistinguishedNameEntry.  This is used for associating information
    with globally defined objects.  This approach should be used where
    the number of objects in the table is small or very sparsely
    spread over the DIT. In other cases where there are many objects
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