Re: WG Charter Proposal v2

Hi Kurt,
	While I understand that LDUP is currently going through a
re-charter exercise, I believe that this re-charter should be
grounded in the existing charter.  Multi-master replication is
clearly a major task given to LDUP in the existing charter--it
is "bullet one" so to speak.  It seems clear to me that its presence
in the original charter reflects a view of the IETF community
that replication would be a valuable addition to the future
of the LDAP service constellation.
	Requiring that the working group take appropriate care
not to make capricious changes to the core service to which it
applies is appropriate, and I believe the Chairs have been
clear that it is their intent to take due care on this point.  I
assume that you and other working group members will
also be following the work carefully, and that issues which
require broad community review can be coordinated among
the interested parties.
	That coordination should not imply prior restraint, if
you will pardon the borrowing from a different area.
There is a fine line between requiring that due care be taken and
requiring that the working group limit its efforts in ways that
may mean that it cannot produce its deliverables.  From my
perspective, LDUP  has already been chartered to produce
the best replication system it can; after producing it, the WG
can exercise its best judgment as to whether that product is
ready for the standards track or should be documented as
experimental.   That judgment should obviously be informed
by coordination with other groups as and after the replication service
is developed.
	I am happy that you will be writing a draft to document
your concerns.  As you do so, I would personally find it
valuable if you documented what changes to the service
model you believe might be required to bring the LDAP service
model and replication together.  Obviously, no one one
wants to make needless changes, but we do need to be
open to extension in order to ensure that the suite of
LDAP services are as complete as possible as we move forward.
	Thanks again,
					best regards,
						Ted Hardie

On Wednesday, April 2, 2003, at 10:51 AM, Kurt D. Zeilenga wrote:

>
> At 09:58 PM 4/1/2003, Chris Apple wrote:
>
>> -----Original Message-----
>> From: [email protected] 
>> [mailto:[email protected]] On
>> Behalf Of Kurt D. Zeilenga
>> Sent: Tuesday, April 01, 2003 9:25 PM
>> To: Mark C Smith
>> Cc: [email protected]; [email protected]
>> Subject: Re: WG Charter Proposal v2
>>
>>
>>
>> At 11:32 AM 4/1/2003, Mark C Smith wrote:
>>> Chris Apple wrote:
>>>> Well, for starters:
>>>>  The following activities are beyond the scope of this WG:
>>>>        Revising the LDAP "core" technical specification [RFC3377
>>>>        and its normative references] (including its information
>>>>       and service models).
>>>>
>>>> CWA> This is an old discussion based on a perusal of the mailing
>>>>     list archive. However, since views may be different now than
>>>>     in the past. I think its worth waiting for others to weigh
>>>>     in on the issue. If a substantial portion of other WG members
>>>>     state their agreement on the mailing list that the suggested
>>>>     text be included, John and I can consider whether consensus
>>>>     exists on adding it.
>>>
>>> The working group should proceed with caution. If we adopt a 
>>> statement such
>> as suggested above, an argument could be made that any form of 
>> multimaster
>> replication requires an extension of the LDAP models... which means 
>> such a
>> charter statement might prevent the WG from progressing some (most?) 
>> of the
>> LDUP documents.
>>
>> Yes, the current documents being produced by the WG assume
>> this WG is chartered to revise the LDAP "core" technical
>> specification (specifically, LDUP changes the LDAP
>> service model) and that's obviously problematic.
>>
>> CWA> Speaking as a Co-Chair, The WG has achieved consensus
>>     on pursuing an experimental publication path - the documents
>>     (with the exception of LCUP) produced by this WG, if they
>>     actually do *require* changes to the LDAP core specifications
>>     to be considered implementable, would surely lead to 
>> *experimental*
>>     updates and not standards track revisions. So from a process
>>     point of view this situation, if it actually becomes a
>>     reality, is not as problematic as implied above.
>
> I think an experimental LDUP would be even more problematic
> as it update the service model in a way which would break
> non-LDUP-aware clients which excepted standard-track behavior
> from the LDUP-aware LDAP servers they peer with.
>
>> However, if the WG intents to continue under that assumption
>> that it can revise as necessary the LDAP "core" technical
>> specification, then it should say so in its charter.
>>
>> Or say nothing about this in the charter.  That I don't recommend.
>>
>> Kurt
>>
>> CWA> The WG has always intended to handle LDUP specification with
>>     LDAPv3 extensibility mechanisms.
>
> The issue is not what mechanisms is used, but whether or
> not LDUP specifications revise the LDAP information and service
> models in a manner which breaks non-LDUP-aware LDAP implementations.
>
>> Initiating any standards
>>     track revisions or updates to the core LDAP specifications
>>     would be a last resort. So I don't yet buy into your claim
>>     that the existing documents assume that LDUP is chartered
>>     to revise the core LDAPv3 specifications. Speaking as a WG
>>     member, I'll need some justification of that claim to evaluate
>>     it.
>
> I suggest you review the archives of past discussions in this
> area.  Here's one URL on the topic (at the head of this thread
> you will find an example of a conformant (and common) LDAP use
> scenario which LDUP will break.)
>   http://www.imc.org/ietf-ldup/mail-archive/msg00672.html
>
> As folks seem not to get the impact MM will have on current
> conformant LDAP deployments, I will prepare an I-D on the
> subject.  My working title is "Multi-master replication
> considered harmful to LDAP/X.500 directory services".
>
>> CWA> Please point out to the WG which LDUP features are impossible
>>     or impractical to realize without revising the core LDAPv3
>>     specifications,
>
> Multi-master replication without tight data consistency between
> the client issuing the modification and the set of master replicas.
>
>> which of those specifications need to
>>     be revised,
>
> I suspect most would have to be changed.
>
>> and how those specifications need to be revised
>>     for each LDUP feature identified as such.
>
> Basically, they have to ensure that if a modify succeed iff
> the update was made to all masters and if a modify failed,
> no update to any master is made.  That is, the service
> provided to a client in the same regardless of whether there
> is one master or many.
>
> Alternatively, eliminate multi-master support.
>
>> You should also
>>     provide a proof or some justification of why each of these
>>     features is impossible or impractical to realize using an
>>     appropriate combination of LDAPv3 extensibility mechanisms.
>
> As I said above, I will write an I-D will details how the
> introduction of loss-consistency multi-master replication
> will break directory applications.
>
>>     This is the only way for myself or any other WG member to
>>     determine if we agree with your belief that this issue is
>>     significant enough to address in the charter revision.
>
> Unfornately, I doubt I'll be able to produce an I-D before the
> charter revision cutoff.  However, I would hope most LDUP'ers
> understand the LDAP service model issue.  It's been discussed
> repeatedly on this list.
>
> Kurt
>
>