Subject: RE: WG Charter Proposal v2

From: "Kurt D. Zeilenga" <[email-masked]>
Date: Mon, 31 Mar 2003 23:52:00 -0800

At 10:39 AM 3/31/2003, Chris Apple wrote:
>Comments embedded below.
>Chris.
>
>-----Original Message-----
>From: Kurt D. Zeilenga [mailto:[email-masked]] 
>Sent: Thursday, March 27, 2003 5:12 PM
>To: [email-masked]
>Cc: [email-masked]; John Strassner
>Subject: Re: WG Charter Proposal v2
>
>
>In reading the proposed WG description, I found a discussion
>of this WG "was originally chartered" to deliver but I couldn't
>any statement as what the WG "is chartered" to delivered,
>
>CWA> There is language there which treats this topic as implicit.
>     I have included some additional text below to make the connection
>     between the original WG direction and the new WG direction more
>     explicit. This additional text is incorporated into the WG
>     description as included by you in the posting to which I am
>     replying now.

The added text helps... I'm still a bit confused though.  I
thought this WG concluded that it wasn't going to reach
consensus on LDUP and hence were not going to be able
to complete it and, instead, would publish what it had done
basically "as is" as experimental/informational with an
additional document which detailed the major outstanding
issues as indicated in Proposal 1 (in particular 1B).

This charter appears to have the WG completing LDUP engineering,
albeit producing a complete protocol technical specification.

>nor could I find any statement of what work is considered
>beyond the scope of the WG.
>
>CWA> If you have suggestions for how to phrase what work is
>     out of scope for LDUP in a sentence or two, I'm certainly
>     open to considering its inclusion. Otherwise, without a
>     "second" from a few other WG members, I will have to treat
>     this comment as an isolated one and one that doesn't
>     represent consensus.

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).

I would also like to see some statement which states that WG
intends avoid achieve a speedy conclusion by documenting areas
of contention instead of entering into protracted debate.  For
example,
        The WG intends to achieve a speedy conclusion by
        documenting areas of contention instead of entering
        into protracted debate.

Kurt

---

From: "Chris Apple" <[email-masked]>
Date: Tue, 1 Apr 2003 12:48:14 -0500

Comments embedded below.

Chris.

-----Original Message-----
From: Kurt D. Zeilenga [mailto:[email-masked]] 
Sent: Tuesday, April 01, 2003 2:52 AM
To: [email-masked]
Cc: [email-masked]
Subject: RE: WG Charter Proposal v2

CWA> The WG achieved consensus on Proposal 1. This proposal
     doesn't state that the WG couldn't reach consensus
     on LDUP, it acknowledges that there are certain issues on
     which consensus cannot be established at this time. That
     is different than stating that we cannot establish any
     consensus at all - which is what your words imply above.

     Proposal 1 was one of two proposals for how to conclude
     LDUP's work given that there are known to be certain issues
     around which consensus cannot be established at this time.
     Proposal 1 also was based on the assumption (which was
     validated by the WG achieving consensus on it) that there
     is sufficient value to justify a recommendation to the ADs
     for consideration for publication as largely experimental
     and informational documents in the work on which we have
     achieved consensus. LCUP being a notable exception as
     indicated in Proposal 1.

     Item 1B of that proposal doesn't state that there should
     be a separate document identifying outstanding issues. It
     also doesn't preclude that. The text of 1B implies that
     outstanding issues should be identified within existing
     documents. Item 1B also doesn't require that course of
     action. I left it intentionally fuzzy because I didn't
     want to restrict the WG from handling it the way it saw
     fit while doing the work. As long as the intent and work
     required to address this is reflected somewhere in the
     WG description (I believe they are), we don't need to
     decide now if it should be handled within existing  
     documents or in a separate document.

Well, for starters:

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.

CWA> Same song as above. We need to see agreement posted to
     the mailing list that it be added. Then John and I will
     consider consensus on this issue.

Kurt

---

From: [email-masked] (Mark C Smith)
Date: Tue, 01 Apr 2003 14:32:47 -0500

>      text be included, John and I can consider whether consensus

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.

-Mark Smith
  Netscape

---

From: "Kurt D. Zeilenga" <[email-masked]>
Date: Tue, 01 Apr 2003 18:24:54 -0800

At 11:32 AM 4/1/2003, Mark C Smith wrote:
>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.

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

---

From: "Chris Apple" <[email-masked]>
Date: Wed, 2 Apr 2003 00:58:07 -0500

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of Kurt D. Zeilenga
Sent: Tuesday, April 01, 2003 9:25 PM
To: Mark C Smith
Cc: [email-masked]; [email-masked]
Subject: Re: WG Charter Proposal v2

At 11:32 AM 4/1/2003, Mark C Smith wrote:
>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.

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. 

Kurt

CWA> The WG has always intended to handle LDUP specification with
     LDAPv3 extensibility mechanisms. 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.

CWA> Please point out to the WG which LDUP features are impossible
     or impractical to realize without revising the core LDAPv3
     specifications, which of those specifications need to
     be revised, and how those specifications need to be revised
     for each LDUP feature identified as such. 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.
     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.

Chris Apple - Principal Architect

DSI Consulting, Inc.

mailto:[email-masked]

http://www.dsi-consulting.com

---

From: "Kurt D. Zeilenga" <[email-masked]>
Date: Wed, 02 Apr 2003 10:51:18 -0800

>     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.

>     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

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".

>     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

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.

>     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

---

From: "Chris Apple" <[email-masked]>
Date: Wed, 2 Apr 2003 14:31:43 -0500

-----Original Message-----
From: Kurt D. Zeilenga [mailto:[email-masked]] 
Sent: Wednesday, April 02, 2003 1:51 PM
To: [email-masked]
Cc: [email-masked]
Subject: RE: WG Charter Proposal v2

>>The working group should proceed with caution. If we adopt a statement
such

CWA> I think you may be missing the point of the experimental
     publication path. Part of the point that you make above
     will have to be noted as a known issue in the documents
     that LDUP will seek to progress. You may not agree with
     the working group consensus that such a path is useful
     and indeed you seem to be advocating that an experimental
     LDUP is even harmful if used in the context of multi-master
     replication. There isn't anything wrong per se with your
     holding that viewpoint, but I need to remind you as a
     co-chair that this particular comment/thread is not
     in line with an already established WG consensus on how
     we will proceed.

CWA> Already did.

CWA> Again, it is WG consensus to note such issues as known and
     move on with experimental publication.

CWA> Point noted - it will have to be described with appropriate
     caveats in the experimental documents that are published.

CWA> Without a specific analysis its not possible for anyone to fully
     understand the magnitude or impact of such updates/revisions/etc.
     on experimental/pilot implementations and deployments and how those
     are likely to interact (or not) with standards-based implementations.
     Again, that's behind part of the motivation for pursuing experimental
     rather than standards track publication.

CWA> Which is one thing that LDUP document editors need to
     be aware of as they revise their documents one final time.
     Some documents will need to have statements included that
     identify this as an uncertain/unknown/underspecified area.

Kurt

CWA> I'm sure they do understand this issue. Also, I think that
     Mark Smith used a word in his original reply to this portion
     of the thread. The implication that it may be possible to
     to address the complexity of multi-master replication
     with an extension to rather than a revision of the core
     service model. Perhaps Mark can elaborate a bit to clarify
     his intended meaning?

DSI Consulting, Inc.

---

From: Ted Hardie <[email-masked]>
Date: Wed, 2 Apr 2003 12:06:26 -0800

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

---

From: [email-masked] (Mark C Smith)
Date: Wed, 02 Apr 2003 15:56:41 -0500

Chris Apple wrote:
> ...

I do not remember using any magic word. But in my opinion it is 
sufficient for the LDUP documents to specify what impact deployment of 
LDUP replication might have on LDAP clients and to specify how clients 
can, if neccessary, discover that LDUP replication is in use.

-Mark

---

From: "Kurt D. Zeilenga" <[email-masked]>
Date: Wed, 02 Apr 2003 17:20:12 -0800

At 12:56 PM 4/2/2003, Mark C Smith wrote:
>I do not remember using any magic word. But in my opinion it is sufficient for the LDUP documents to specify what impact deployment of LDUP replication might have on LDAP clients and to specify how clients can, if neccessary, discover that LDUP replication is in use.

With LDUP replication documents being published on the
Experimental track, this likely can be handled by clear,
concise, and prominent note providing appropriate warnings,
disclaimers, restrictions, applicability statements, and
such.  This note should also be supplement with more
detailed discussion of the issues, possibly referencing
the I-D I intend to write.  I would be willing to discuss
(at a later date, ~June) this I-D becoming one of the
supplementary informational WG I-Ds discussed in the
proposed charter.

Kurt

---

From: "Chris Apple" <[email-masked]>
Date: Thu, 3 Apr 2003 02:37:41 -0500

Mark,

Sorry for being obtuse. You used the word extension in
relation to the LDAP models.

"...an argument could be made that any form of 
multimaster replication requires an extension of
the LDAP models..."

I was looking for some clarification about what you
could have meant by extension in this context.

The suggestion below seems quite reasonable for editors to
consider during their final revisions of LDUP documents.

DSI Consulting, Inc.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of Mark C Smith
Sent: Wednesday, April 02, 2003 3:57 PM
To: [email-masked]
Cc: [email-masked]
Subject: Re: WG Charter Proposal v2

-Mark

---

From: [email-masked] (Mark C Smith)
Date: Thu, 03 Apr 2003 09:17:24 -0500

> consider during their final revisions of LDUP documents.

I meant "extension" in the most general sense of the word. I think 
Kurt's point is that if multimaster replication (MMR) is deployed, there 
are certain things that LDAP clients can no longer assume to be true. 
For example, a client can no longer assume that only one writeable copy 
of an entry exists. Because that knowledge may be really important to a 
client, LDUP should perhaps provide a way for clients to discover that 
MMR is in use. But I don't think most proprietary MMR implementations 
both providing such a discovery mechanism so one could argue this is not 
a big problem in practice.

Certainly it seems to me that experimental RFCs are just that: 
experimental. If problems are discovered by the brave implementers and 
deployers who adopt such as RFC, then the specifications can be revised 
or we can all conclude that the experiment was a failure. No one HAS to 
use any of this stuff.

-- 
Mark Smith
Netscape Directory Product Development
My words are my own, not my employer's.