Subject: RE: [Capwap] Taxonomy Recommendations

From: "Yang, Lily L" <[email-masked]>
Date: Wed, 15 Jun 2005 13:19:02 -0700

Hi, Pat and Mani --

I have not read through the entire Taxonomy Recommendations document
yet, but just reading through the first few pages, I believe the authors
are correct in pointing out one of the "inconsistency" (error) in the
taxonomy draft. There was a paragraph in the taxonomy draft Section 5.6:
" The commonalities and differences between Local MAC and Split MAC are
   most clearly seen by comparing Figure 7 to Figure 10.  The
   commonality is that 802.11 control frames are terminated at WTPs in
   both cases.  The main difference between Local MAC and Split MAC is
   that the WTP terminates only the 802.11 control frames in the Split
   MAC, while the WTP may terminate all 802.11 frames in the Local MAC.
   An interesting consequence of this difference is that the Integration
   Service, which essentially refers to bridging between 802.11 and
   802.3 frames, is implemented by the AC in the Split MAC, but can be
   part of either the AC or WTP in the Local MAC."
The last sentence, as pointed out by Pat, Bob and Inderpreet's document,
was incorrect. According to Figure 9, Integration Service, for all the
parties classified as Local MAC, is implemented by WTP. 
Given that we still have about 3 hours remaining in the authors' 48 hour
window, I would like to send a note to RFC Editor suggesting the
following sentence to replace the last sentence in the paragraph:
"An interesting consequence of this difference is that the Integration
   Service, which essentially refers to bridging between 802.11 and
   802.3 frames, is implemented by the AC in the Split MAC and by the
WTP in the Local MAC, as shown in Figure 9 and Figure 12."

Glaring as it is, I believe this error does not carry any far reaching
implication to the entire document and hence it is bug we can fix right
now.

Regarding the comment from the authors that taxonomy draft lacks
conclusion and recommendation and hence the motivation to take it
further to clearly define what Local and Split MAC really mean in terms
of functional split -- I think that is a fair comment -- Personally I
was tempted to take that step in the taxonomy draft with the intention
to help the WG moving forward, but as the editor of the draft, I
received clear instruction from the chairs and the WG that a taxonomy
only goes so far to "document" the reality of the market, not to
"define" any architectures. So the draft deliberately didn't go far into
making any specific functional split recommendation.

As I advocated in both July and Nov IETF meeting last year, I believe
there is indeed a gap between taxonomy draft and objective draft -- the
WG needs a clear definition of the functional split for Local,
especially Split MAC, but that is not the charter of either taxonomy
draft or Objective draft. Some people have the illusion that IEEE 802.11
(specifically the APF ad hoc group) will provide such definition. The
clear answer there is NO, IEEE would not do that. It is up to us in this
group to agree on the split and move on. So if indeed this Taxonomy
Recommendation draft fulfills this purpose, I personally believe it is a
very necessary step to take in order to move forward. However, as I
said, I have not reviewed the entire document yet and so I would reserve
until then to offer any further comments.

But I do want to fix the error in Section 5.6 in Taxonomy draft NOW. 

Lily
-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of Mani, Mahalingam (Mahalingam)
Sent: Wednesday, June 15, 2005 11:14 AM
To: Pat Calhoun; [email-masked]
Subject: RE: [Capwap] Taxonomy Recommendations

Thanks for the joint effort (by authors of two candidate protocols for
eval. as I see it) in making a case for clarification of terminology.

If the changes and clarifications proposed are extensive - comments in
form of I-D is useful to place-hold them.

The WG should (especially the original taxonomy team authors) comment on
these comments (draft): WG has approved the -06 version of the taxonomy
draft. Two of the authors are in this as well :)

It is also important to understand the implications, if any, (on
Objectives draft) if WG agrees to any of the proposed clarifications. It
may turn out to be transparent to the Objectives draft. This needs to
happen soon for Objectives to freeze and let the evaluation team use a
baselined version.

[BTW: the taxonomy draft is in RFC editor's queue - actually just
completed AUTH48].

-mani
======
-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of Pat Calhoun
Sent: Thursday, June 09, 2005 2:28 PM
To: [email-masked]
Subject: [Capwap] Taxonomy Recommendations

All,
 
I wanted to announce the early availability of the CAPWAP taxonomy
recommendation draft that Bob O'Hara Inderpreet Singh and I have been
working on. It can be found at
http://www.capwap.org/draft-calhoun-capwap-taxonomy-recommendation-00.tx
t.

Abstract

   The IETF's CAPWAP working group has documented various product
   architectures and has categorized the Centralized WLAN Architectures
   into two main buckets: Split and Local MAC.  While the document
   contains very relevant and useful information, what it does is list
   the architectural variants of these two buckets, but does not
   unambiguously define either the Split MAC or Local MAC architectures.
   In order for CAPWAP to be successful, it is crucial for the protocol
   evaluation team, and the working group, to agree on unambiguous
   terminology to describe these architectures.

   This document proposes terminology to unambiguously describe the
   relevant architectures found in the taxonomy document, for the
   purpose of initiating a discussion within the working group and to
   allow the protocol evaluation work to come to a fruitful conclusion.
   We conclude in this document that the architectures are very similar
   and could be supported via a single protocol.

Pat Calhoun
CTO, Wireless Networking Business Unit
Cisco Systems

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---

From: "Pat Calhoun" <[email-masked]>
Date: Thu, 16 Jun 2005 06:51:53 -0700

Lily, I agree with your recommended change (and note the RFC editor will
wait for your comments - even past the 48 hour window. Just make sure you
inform them that you have changes and they will hold off).

Further, I would like to stress the point made by Lily where there is a gap
between the current taxonomy document and the objectives. The taxonomy
recommendations is not intended to change any of the objectives per se (to
address Mani's question), but it does attempt to provide a single frame of
reference for the WG in our definitions of Split vs. Local MAC.

Pat Calhoun

> From: Yang, Lily L [mailto:[email-masked]] 
> Sent: Wednesday, June 15, 2005 1:19 PM
> To: Mani, Mahalingam (Mahalingam); Pat Calhoun
> Cc: [email-masked]
> I have not read through the entire Taxonomy Recommendations 
> document yet, but just reading through the first few pages, I 
> believe the authors are correct in pointing out one of the 
> "inconsistency" (error) in the taxonomy draft. There was a 
> paragraph in the taxonomy draft Section 5.6:
> The last sentence, as pointed out by Pat, Bob and 
> Inderpreet's document, was incorrect. According to Figure 9, 
> Integration Service, for all the parties classified as Local 
> MAC, is implemented by WTP. 
> Given that we still have about 3 hours remaining in the 
> authors' 48 hour window, I would like to send a note to RFC 
> Editor suggesting the following sentence to replace the last 
> sentence in the paragraph:
>    802.3 frames, is implemented by the AC in the Split MAC 
> and by the WTP in the Local MAC, as shown in Figure 9 and Figure 12."
> 
> Glaring as it is, I believe this error does not carry any far 
> reaching implication to the entire document and hence it is 
> bug we can fix right now.
> 
> Regarding the comment from the authors that taxonomy draft 
> lacks conclusion and recommendation and hence the motivation 
> to take it further to clearly define what Local and Split MAC 
> really mean in terms of functional split -- I think that is a 
> fair comment -- Personally I was tempted to take that step in 
> the taxonomy draft with the intention to help the WG moving 
> forward, but as the editor of the draft, I received clear 
> instruction from the chairs and the WG that a taxonomy only 
> goes so far to "document" the reality of the market, not to 
> "define" any architectures. So the draft deliberately didn't 
> go far into making any specific functional split recommendation.
> 
> As I advocated in both July and Nov IETF meeting last year, I 
> believe there is indeed a gap between taxonomy draft and 
> objective draft -- the WG needs a clear definition of the 
> functional split for Local, especially Split MAC, but that is 
> not the charter of either taxonomy draft or Objective draft. 
> Some people have the illusion that IEEE 802.11 (specifically 
> the APF ad hoc group) will provide such definition. The clear 
> answer there is NO, IEEE would not do that. It is up to us in 
> this group to agree on the split and move on. So if indeed 
> this Taxonomy Recommendation draft fulfills this purpose, I 
> personally believe it is a very necessary step to take in 
> order to move forward. However, as I said, I have not 
> reviewed the entire document yet and so I would reserve until 
> then to offer any further comments.
> 
> From: [email-masked] 
> [mailto:[email-masked]] On Behalf Of Mani, 
> Mahalingam (Mahalingam)
> Thanks for the joint effort (by authors of two candidate 
> protocols for eval. as I see it) in making a case for 
> clarification of terminology.
> 
> If the changes and clarifications proposed are extensive - 
> comments in form of I-D is useful to place-hold them.
> 
> The WG should (especially the original taxonomy team authors) 
> comment on these comments (draft): WG has approved the -06 
> version of the taxonomy draft. Two of the authors are in this 
> as well :)
> 
> It is also important to understand the implications, if any, 
> (on Objectives draft) if WG agrees to any of the proposed 
> clarifications. It may turn out to be transparent to the 
> Objectives draft. This needs to happen soon for Objectives to 
> freeze and let the evaluation team use a baselined version.
> 
> [BTW: the taxonomy draft is in RFC editor's queue - actually 
> just completed AUTH48].
> 
> -mani
> ======
> From: [email-masked] 
> [mailto:[email-masked]] On Behalf Of Pat Calhoun
> I wanted to announce the early availability of the CAPWAP 
> taxonomy recommendation draft that Bob O'Hara Inderpreet 
> Singh and I have been working on. It can be found at