Last Modified: 2003-10-16
o Multi-Master Replication - A replication model where entries can be written and updated on any of several replica copies, without requiring communication with other masters before the write or update is performed.
o Master-Slave, or Single-Master Replication - A replication model that assumes only one server, the master, allows write access to the replicated data. Note that Master-Slave replication can be considered a proper subset of multi-master replication.
Recently, the WG established consensus on a change of direction to pursue publication of a standards track protocol for LDAPv3 client synchronization, an experimental LDAPv3 replication protocol, and supporting informational documents. Thus the new work program is largely the same as the original work program with one notable exception, the LDAPv3 replication protocol is intended to be an experimental rather than a standards track protocol.
The WG's approach was to first develop a set of requirements for LDAPv3 directory replication and write an applicability statement defining scenarios on which replication requirements are based. An engineering team was formed consisting of different vendors and the co-chairs in order to harmonize the existing approaches into a single standard approach. All of these have been accomplished during the pre-working group stage. It should be noted, however, that replication using heterogeneous servers is dependent on resolving access control issues, which were the domain of other working groups. Because the responsible WG failed to achieve consensus on a standard access control model for LDAPv3, the LDUP WG formed a design team to explore the issue of how to address the lack of such a model in the context of LDAPv3 replication. This design team made recommendations to the working group. The working group considered these recommendations and consensus was established on addressing these recommendations in the context of revising other working group deliverables rather than adding new deliverables specific to access control for replication. Largely because of the lack of a standard access control model for LDAPv3, the working group also established consensus on pursuing an experimental or informational publication path for a majority of working group documents formerly intended to become proposed standards.
The new replication architecture supports all forms of replication mentioned above. Seven areas of working group focus have been identified through LDUP Engineering Team discussions, each leading to one or more documents to be published:
o LDAPv3 Replication Architecture
This documents a general-purpose LDAPv3 replication architecture, defines key components of this architecture, describes how these key components functionally behave, and describes how these components interact with each other when in various modes of operation
o LDAPv3 Replication Information Model
Defines the schema and semantics of information used to operate, administer, maintain, and provision replication between LDAPv3 servers. Specifically, this document will contain common schema specifications intended to facilitate interoperable implementations with respect to:
+ replication agreements
+ consistency models
+ replication topologies
+ managing deleted objects and their states
+ administration and management
o LDAPv3 Replication Information Transport Protocol
LDAPv3 extended operation and control specifications required to allow LDAPv3 to be used as the transport protocol for information being replicated
o LDAPv3 Replica Management
Specifications designed to support administration, maintenance, and provisioning of replicas and replication agreements. These specifications may take the form of definitions for LDAPv3 extended operations, controls, and/or new schema elements.
o LDAPv3 Update Reconciliation Procedures
Procedures for detection and resolution of conflicts between the state of multiple replicas that contain information from the same unit of replication.
o A General Usage Profile of the LDAPv3 Replication Architecture, Information Model, Protocol Extensions, and Update Reconciliation Procedures.
o LDAPv3 Client Update
A protocol that enables an LDAP client to synchronize with the content of a directory information tree (DIT) stored by an LDAP server and to be notified about the changes to that content.
The work being done in the LDUP WG should be coordinated to the closest extent possible with similar work being done in the ITU. This is necessary both because LDAP depends on X.500 and because it makes sense from an operational perspective.
|Done||Submit I-D on LDAPv3 Directory Replication Requirements.|
|Done||Submit Internet-Draft on LDAPv3 Replication Information Model|
|Done||Submit I-D on LDAPv3 Update Reconciliation Procedures.|
|Done||Revise I-D on LDAPv3 Directory Replication Requirements.|
|Done||Revise I-D on LDAPv3 Replication Architecture.|
|Done||Revise I-D on LDAPv3 Replication Information Model.|
|Done||Submit I-D on LDAPv3 Replication Information Transport Protocol.|
|Done||Revise I-D on LDAPv3 Replication Architecture.|
|Done||LDAPv3 Directory Replication Requirements I-D goes to WG Last Call as Informational.|
|Done||Submit I-D on LDAPv3 Mandatory Replica Management.|
|Done||Submit I-D on LDAPv3 Replication General Usage Profile|
|Apr 03||Revise LDAPv3 Replication Information Model I-D|
|Done||Revise LDAPv3 Client Update Protocol I-D|
|Done||LDAPv3 Client Update Protocol I-D goes to WG Last Call as Proposed Standard|
|May 03||Revise LDAPv3 Update Reconciliation Procedures I-D|
|May 03||Revise LDAPv3 Replication Architecture I-D|
|Jun 03||LDAPv3 Replication Information Model I-D goes to WG Last Call as Informational|
|Jun 03||LDAPv3 Replication Architecture I-D goes to WG Last Call as Informational.|
|Jun 03||Revise LDAPv3 Replication General Usage Profile I-D|
|Jul 03||Revise LDAPv3 Replication Information Transport Protocol I-D|
|Jul 03||Revise LDAPv3 Replica Management I-D|
|Jul 03||Evaluate Deliverables Status|
|Aug 03||LDAPv3 Replication Information Transport Protocol I-D goes to WG Last Call as Experimental|
|Aug 03||LDAPv3 Update Reconciliation Procedures I-D goes to WG Last Call as Experimental|
|Aug 03||LDAPv3 Mandatory Replica Management I-D goes to WG Last Call as Experimental|
|Sep 03||LDAPv3 Replication General Usage Profile I-D goes to WG Last Call as Informational|
|RFC3384||I||LDAPv3 Replication Requirements|
LDUP WG Meeting Minutes TUESDAY, November 11, 2003 1415-1515 Afternoon Sessions II Rochester APP ldup LDAP Duplication/Replication/Update Protocols WG Kurt Zeilenga volunteered to take notes for the meeting minutes. Chris Apple chaired the meeting and presented the previously circulate meeting agenda. No changes were requested. Chris gave a presentation on the general WG status that concluded with a recommendation from the chairs that WG Last Call for various documents should proceed in a sequence consistent with the order listed in the WG Charter. Chris also pointed out that this would likely be the last IETF Meeting at which LDUP has a need to meet face-to-face. John McMeeking gave a status update of infomod/mrm/protocol I-Ds. Infomod is ready for WG Last Call. Protocol is close to done. MRM needs some more work. Chris Apple noted that the: + Editors of Information and Architectural Models have requested that a last call be initiated + Editors of General Usage Profile document report being ready for WG Last Call + Editors of URP indicate that the document is ready for WG Last Call Ted Hardie pointed out that some documents seem to be missing from the WG Charter page; Chris Apple replied that they were expired and need to be refreshed. Chris presented a proposal for managing WG last Call that was discussed. After identifying a few issues related to dependencies and remaining work to Be done on certain documents, the following schedule was settled upon: + First Grouping: Information and Architectural Model Documents (2 week duration) + Second Grouping: URP and Protocol (3 week duration) + Third Grouping: General Usage Profile and MRM (3 week duration) The original proposal indicated starting WG Last Call for the first grouping on the first Monday after the IETF Last Call. But it was decided in the meeting that this would happen as soon as possible, but not necessarily on that particular day because John McMeeking noted that there may need to be some changes to infomod. draft-ietf-ldup-infomod-08 might be revised prior to WG Last Call. Chris suggested not deferring the WG Last Call if the changes are minor. No concerns were voiced about this. Ted Hardie asked whether the documents should be subject to IETF-wide last call or not. Chris to consider the issue and ask WG (on the mailing list) for input. The meeting concluded.