RE: Proposed LDUP Charter

[Alan Lloyd <Alan.Lloyd@xxxxxxxxxxxxxxxxxxxx>]

Ed thanks for that - good input. 
Here is a view re MM. I have also got a "impure" paper on our web site
re backbone issues.
some good points.
a) Directory topologies. Replicated directories intermingle with a
distributed directories. ie. One should always design the distributed
components/requirements of a directory system first and then apply
replication components for backup or local access requirements. I have
seen many "replicated" system put together without any consideration for
distribution with the obvious results. High operational costs, low
integrity in the information, and a nightmare to manage if the
information dynamics are high.

With X.500 one can deal with distribution in many ways. ie with Root
level DSA and subordinates, a range of First level DSAs that mulicast
when Root level Search/Lists are performed (these FLDSAs also have
subordinate DSAs if required).
In addition, we can run our DSA without a database as DAP/LDAP, DSP,
DISP router so that multiplexing and interconnection of top level DSAs
can be effected in the most optimum way. In addition we can couple LDAP
servers to our DSAs.

Now given that some components of this system may need replicating for
backup reasons and others for local access, etc. It is fundamental that
knowledge references and naming contexts are dealt with correctly for
Search /List etc and master/replica contexts are known.

The point here is that I think its not very useful to define a
replication protocol/process for directory systems untill one has a firm
grip on the distribution and topology issues. Unless one is just
considering simple server to simple server replication.



b) With serious multi master mode, one needs serious engineering and
that is not a simple protocol. As said we can use the commercial DB
replicators that do very fast, robust replication below the X.500 level
of operations - as well as tools, DISP and LDIF. 
The point here is that if the commercial world wants serious multi
master facilities - I dont think LDAP the way it stands will do the job.
It has no robustness.

just thoughts and regards alan.

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From: Ed Reed
To: ietf-ldup@xxxxxxx; capple@xxxxxxxxxxxxxxxxxxxxxx;
Alan.Lloyd@xxxxxxxxxxxxxxxxxxxx
Sent: 9/25/98 1:25:57 AM
Subject: RE: Proposed LDUP Charter

My take is that X.500 DISP is a likely candidate for another
replication mechanism which might be indicated on 
replication agreements, but it doesn't address the accepted
requirement for multi-master replication.  We know there will
be others defined, but the one we're defining here is the
multi-master mechanism to be standardized.  It's likely that
profile of usage we write which shows how to use this 
mechanism for single-master configurations will map well
onto DISP, but with differences in how things are represented
in transfer and in configuration.

Instructing clients as to how to leverage the new knowledge
about where replicas of data may be found, and indeed, 
which replicas hold which data (for incomplete replicas) is
identified as work that needs to be done, but is outside
the limited scope of LDUP.  I think something informed by
the Hierarchical Operations of X.519, and perhaps NDS, 
needs to be worked in here, in the broader context of
distributed LDAP operations.

Regards,
Ed

----------------------
Ed Reed, Technologist
Novell, Inc.
+1 801 861-3320

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