1

Scope

1.1

General Although ISO/IEC 9594-4 / CCITT X.518 describes the DSA procedures relating to referrals and Search Continuation References, this part of ISO/IEC ISP 10615 does not define the DUA's role in acting upon these procedures.

This part of ISO/IEC ISP 10615 specifies the behaviour of DUAs when they use DAP to access multiple DSAs in the course of making a single original enquiry without human intervention in the formulation of protocol. Multiple enquiries result from receiving continuation references embedded in referrals, list results or search results.

DUAs which do not have the capability of following referrals or Search Continuation References without human intervention in the formulation of protocol are not within the scope of this part of ISO/IEC ISP 10615 for the purposes of conformance, although its recommendations may be of value.

NOTE - The conformance requirements of this part of ISO/IEC ISP 10615 presume the scenario depicted in Figure 1: human intervention (if any) is restricted to the possibility of a ""go/ no-go"" decision; in the case of conformance testing, each such decision is presumed to be ""go"".

The scope of this part of ISO/IEC ISP 10615 is limited to matters of procedure in exercising the DAP protocol, and does not cover enhancements of service. It does not cover any (DAP) protocol encoding issues.

NOTE - In the absence of this part of ISO/IEC ISP 10615, the implementor of a DUA with the capability of following continuation references automatically will need to make design decisions about the behaviour of the DUA when doing so. An aim of this part of ISO/IEC ISP 10615 is to minimise uncertainty and enhance consistency in making design solutions by means of functional standardisation. This part of ISO/IEC ISP 10615 adds no spurious complexity, given that the requirement pre-exists to follow continuation references automatically.

1.2

Position within the taxonomy This part of ISO/IEC ISP 10615 is identified in ISO/IEC TR 10000-2 as ADI31 ""Directory-Distributed Operations - DUA Support of Distributed Operations"".

1.3

Scenario This part of ISO/IEC ISP 10615 profiles the autonomous behaviour of DUAs when Referrals or Search Continuation References are used by the Directory.

A DUA creates an association to a DSA of its choice, and invokes an operation. The DSA may return a referral instead of a result, or the result may contain continuation references. The latter occur in the case of List or Search operations in which the DSA is unwilling or unable to complete the search, but is able to advise which other DSAs may be able to assist.

The possible actions which may then be taken by a DUA, without human intervention except possibly the taking of a ""go/no-go"" decision, are specified in this part of ISO/IEC ISP 10615.