DUA Metrics (OSI-DS 33 (v2))
RFC 1431

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Network Working Group                                          P. Barker
Request for Comments: 1431                     University College London
                                                           February 1993

                              DUA Metrics

Status of this Memo

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

Abstract

   This RFC is being distributed to members of the Internet community in
   order to solicit their reactions to the proposals contained in it.
   While the issues discussed may not be directly relevant to the
   research problems of the Internet, they may be interesting to a
   number of researchers and implementers.

   This document defines a set of criteria by which a DUA
   implementation, or more precisely a Directory user interface, may be
   judged.  Particular issues covered include terminal requirements;
   style of interface; target user; default object classes and attribute
   types; use of DAP; error handling.  The focus of the note is on
   "white pages" DUAs: this is a reflection of the current information
   base.  Nevertheless much of the document will be applicable to DUAs
   developed for other types of Directory usage.

   Please send comments to the author or to the discussion group <osi-
   ds@CS.UCL.AC.UK>.

Table of Contents

   1.  Overview................................................       2
   2.  General Information.....................................       3
   3.  Conformance to OSI Standards............................       5
       3.1    Directory protocols..............................       5
       3.2    Protocol stacks..................................       5
       3.3    Schema ..........................................       5
       3.4    DIT structure  ..................................       5
   4.  Conformance to Research Community Standards.............       6
   5.  The General Style of the DUA............................       6
   6.  Schema..................................................       7
       6.1    Object Classes and Attribute Types...............       7
       6.2    DIT structure....................................       8
   7.  Entering queries........................................       9

Barker                                                          [Page 1]
RFC 1431                      DUA Metrics                  February 1993

   8.  Strategy for locating entries...........................       9
   9.  Displaying results......................................      10
   10. Association Handling....................................      11
   11. Suitability for management..............................      12
   12. Query Resolution........................................      13
   13. International Languages.................................      16
   14. User Friendliness.......................................      16
   15. Operational Use.........................................      17
   16. Security Considerations.................................      19
   17. Author's Address........................................      19

1.  Overview

   The purpose of this document is to define some metrics by which DUA
   products can be measured.  It should be first be noted that the use
   of the term "DUA" is rather misleading.  There is an assumption here
   that the DUA is implemented correctly and is able to "talk" valid
   X.500 protocol: this is a sine qua non.  Instead, this document seeks
   to draw out the characteristics of Directory user interfaces.
   However, the term DUA is persisted with as it is used by most people
   when referring to Directory user interfaces.  The format of these DUA
   metrics is essentially a questionnaire which extracts a detailed
   description of a user interface.  DUAs come in very different forms.
   Many make use of windowing environments, offering a "high-tech" view
   of the Directory, while others are designed to work in a terminal
   environment.  Some interfaces offer extensive control over the
   Directory, and thus may be well-suited to Directory managers, while
   others are aimed more at the novice user.  Some interfaces are
   configurable to allow searches for any attribute in any part of the
   DIT, while others lack this generality but are focussed on handling
   the most typical queries well.  In many aspects, it is almost
   impossible to say that one DUA is better than other from looking at
   the responses to question in this document.  A flexible management
   tool will be better for management than a DUA aimed at servicing
   simple look-ups, and vice-versa.  Furthermore, in other areas, there
   are several radically different approaches to a problem, but it is
   not as yet clear whether one approach is better than another.  One
   example of this is the extent to which a DUA provides an abstraction
   of the underlying DIT hierarchy, either emphasising the world as a