The Lightweight Directory Access Protocol (LDAP) Intermediate Response Message
RFC 3771
| Document | Type |
RFC - Proposed Standard
(April 2004; No errata)
Updates RFC 2251
|
|
|---|---|---|---|
| Last updated | 2015-10-14 | ||
| Stream | ISE | ||
| Formats | plain text pdf html bibtex | ||
| Stream | ISE state | (None) | |
| Consensus Boilerplate | Unknown | ||
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 3771 (Proposed Standard) | |
| Telechat date | |||
| Responsible AD | Ted Hardie | ||
| Send notices to | (None) | ||
Network Working Group R. Harrison
Request for Comments: 3771 Novell, Inc.
Updates: 2251 K. Zeilenga
Category: Standards Track OpenLDAP Foundation
April 2004
The Lightweight Directory Access Protocol (LDAP)
Intermediate Response Message
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract
This document defines and describes the IntermediateResponse message,
a general mechanism for defining single-request/multiple-response
operations in Lightweight Directory Access Protocol (LDAP). The
IntermediateResponse message is defined in such a way that the
protocol behavior of existing LDAP operations is maintained. This
message is intended to be used in conjunction with the LDAP
ExtendedRequest and ExtendedResponse to define new single-
request/multiple-response operations or in conjunction with a control
when extending existing LDAP operations in a way that requires them
to return intermediate response information.
Harrison & Zeilenga Standards Track [Page 1]
RFC 3771 LDAP Intermediate Response April 2004
1. Introduction
The Lightweight Directory Access Protocol (LDAP), version 3 [RFC3377]
is an extensible protocol. Extended operations ([RFC2251] Section
4.12) are defined to allow for the addition of operations to LDAP,
without requiring revisions of the protocol. Similarly, controls
([RFC2251] Section 4.1.12) are defined to extend or modify the
behavior of existing LDAP operations.
LDAP is a client-request/server-response based protocol. With the
exception of the search operation, the entire response to an
operation request is returned in a single protocol data unit (i.e.,
LDAP message). While this single-request/single-response paradigm is
sufficient for many operations (including all but one of those
currently defined by [RFC3377]), both intuition and practical
experience validate the notion that it is insufficient for others.
For example, the LDAP delete operation could be extended via a
subtree control to mean that an entire subtree is to be deleted. A
subtree delete operation needs to return continuation references
based upon subordinate knowledge information contained in the server
so that the client can complete the operation. Returning references
as they are found, instead of with the final result, allows the
client to perform the operation more efficiently because it does not
have to wait for the final result to get this continuation reference
information.
Similarly, an engineer might choose to design the subtree delete
operation as an extended operation of its own rather than using a
subtree control in conjunction with the delete operation. Once
again, the same continuation reference information is needed by the
client to complete the operation, and sending the continuation
references as they are found would allow the client to perform the
operation more efficiently.
Operations that are completed in stages or that progress through
various states as they are completed might want to send intermediate
responses to the client, thereby informing it of the status of the
operation. For example, an LDAP implementation might define an
extended operation to create a new replica of an administrative area
on a server, and the operation is completed in three stages: (1)
begin creation of replica, (2) send replica data to server, (3)
replica creation complete. Intermediate messages might be sent from
the server to the client at the beginning of each stage with the
final response for the extended operation being sent after stage (3)
is complete.
Harrison & Zeilenga Standards Track [Page 2]
RFC 3771 LDAP Intermediate Response April 2004
As LDAP [RFC3377] is currently defined, there is no general LDAP
message type that can be used to return intermediate results. A
single, reusable LDAP message for carrying intermediate response
information is desired to avoid repeated modification of the
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