Subject: [Capwap] Taxonomy Recommendations

From: "Pat Calhoun" <[email-masked]>
Date: Thu, 9 Jun 2005 14:27:55 -0700

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.txt.

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: Dan Harkins <[email-masked]>
Date: Thu, 09 Jun 2005 14:49:29 -0700

Pat,

  I'm sure that everyone appreciates the hard work you've done-- I
certainly do-- but I think it is necessary to note that this is
just a personal submission and does not carry any offical weight
in the working group. 

  As Dorothy has pointed out, we're on a tight timeline here. If
we allow random individual submissions to constrain or influence
our work we'll never get done.

  I do not think your draft should be used to bring protocol
evaluation to a fruitful conclusion. 

  Dan.

On Thu, 09 Jun 2005 14:27:55 PDT you wrote

---

From: "Pat Calhoun" <[email-masked]>
Date: Wed, 15 Jun 2005 05:16:30 -0700

All,

I wanted to follow up on the draft that was sent last week, and explain some
of the justification for this draft. 

When Inderpreet (co-author of the CAPWAP CTP submission), Bob O'Hara and I
(co-authors of the CAPWAP LWAPP submission) discussed the differences
between our respective approaches, it became clear that we did not have
agreement on the definitions of Local and Split MAC. In re-reading the
taxonomy specification, it became clear that while the taxonomy document
lists the various approaches surveyed, it really did not provide a
conclusion or recommendation. Therefore, the reader is left with no clear
understanding the CAPWAP Working Group's definition of these two approaches.

For instance, by following the letter of the taxonomy specification, one
will observe that the split in functionality varies greatly from one
implementation of Local MAC to another. The following is figure 9, taken
directly from the document:

                   Arch7   Arch8   Arch9   Arch10   Arch11
                   -----   -----   -----   ------   ------

      Distribution
      Service       AC     AC       WTP      AC      WTP

      Integration
      Service       WTP    WTP      WTP      WTP     WTP

      Beacon
      Generation    WTP    WTP      WTP      WTP     WTP

      Probe
      Response      WTP    WTP      WTP      WTP     WTP

      Power mgmt
      Packet
      Buffering     WTP    WTP      WTP      WTP     WTP

      Fragmentation/
      Defragment.   WTP    WTP      WTP      WTP     WTP

      Association
      Disassoc.
      Reassociation AC     WTP      WTP      WTP     WTP

      WME/11e
      --------------
      classifying   AC                               WTP

      scheduling    WTP    AC/WTP   WTP      WTP     WTP

      queuing       WTP             WTP      WTP     WTP

      Authentication
      and Privacy
      --------------
      802.1x/EAP    AC      AC      AC/WTP   AC       AC/WTP

      Keys
      Management    AC      AC      WTP      AC       AC

      802.11
      Encryption/
      Decryption    WTP     WTP     WTP      WTP      WTP

    Figure 9: Mapping of 802.11 Functions for Local MAC Architecture

Finally, the secion on Local MAC concludes with the following text:

   From Figure 7, Figure 8 and Figure 9, it is clear that differences
   among vendors in the Local MAC Architecture are relatively minor, and
   most of the functional mapping appears to be common across vendors.

The issue with the above paragraph is that while the differences are
restricted to specific functions (e.g., Distribution Service), these small
differences will significantly change how products operate. In the case of
Distribution Service, it will state whether traffic is tunneled to/from the
WTP or not.

Given the above, Inderpreet, Bob and I collaborated together in order to
come to some agreement on what the differences between both approaches were.
I think that the results of our extensive conversations resulted in the
previously mentioned draft. I would urge the WG to take a look at this
document and provide comments. At a minimum, we believe it would be in the
best interest of the working group to at least discuss whether the taxonomy
document is in need of some conclusions in order to set a frame of reference
in the two main approaches.

Thanks,

Pat Calhoun

> -----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