Subject: [Capwap] Issue 244: Preamble Header Optimization moved from Wish List to Active Issues Database

From: <[email-masked]>
Date: Wed, 4 Apr 2007 13:32:09 -0500

Dear WG,

While reviewing the recently closed issues, it appears that Issue 244,
Preamble Header Optimization, was mistakenly moved to the Wish list
without a clear decision from the WG to do so.  As a result, we'll be
moving issue 244 from the Wish list back into the "features" section of
the database, so that the WG can further discuss this issue and decide
what to do about it.  Issue 244 should be considered an open issue
against the CAPWAP drafts. 

Issue 244 was discussed on the list under issue 224 before the interim
meeting, during the Interim meeting and again further discussed on the
WG list.  The proposed solution was sent to the list on Jan 31, 2007 in
this message:  http://lists.frascone.com/pipermail/capwap/msg04161.html

It does not appear that the WG made a decision on this issue either way,
before it was moved to the Wish list, possibly because the discussion
was lost inside a discussion of related issues.

The WG should consider the proposed solution for Issue 244, and discuss
the following alternatives on the WG list: 

1) Adopt the proposed optimizations
2) Reject the proposed optimizations
3) Move Issue 244 to the Wish list (as this is an optimization, not a
bug fix) for future consideration.

Best Regards,
Mani, Margaret and Dorothy

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---

From: Jim Murphy <[email-masked]>
Date: Wed, 04 Apr 2007 17:10:13 -0700

I support adopting the proposed optimizations.

Thanks,

Jim

[email-masked] wrote:
> this message:  _http://lists.frascone.com/pipermail/capwap/msg04161.html_
> 
> ------------------------------------------------------------------------
>

---

From: "Sudhanshu" <[email-masked]>
Date: Thu, 5 Apr 2007 09:06:10 -0700

I also support for adopting the propose optimization. 

I agree, it is not a bug but an optimization. But since it related to the
data path, it should be considered as important item to address. Moreover
propose solution apply transparently to both data plane as well control
plane and make overall protocol more flexible.

Also it should address the concern of those people who wanted to make data
plane and control plane processing similar.

_Suds

-----Original Message-----
From: Jim Murphy [mailto:[email-masked]] 
Sent: Wednesday, April 04, 2007 5:10 PM
To: [email-masked]
Cc: [email-masked]; [email-masked]; [email-masked]
Subject: Re: [Capwap] Issue 244: Preamble Header Optimization moved from
Wish List to Active Issues Database

Thanks,

Jim

---

From: "Puneet Agarwal" <[email-masked]>
Date: Thu, 5 Apr 2007 14:44:19 -0700

I support optimizations of the preamble hdr.

Thanks.

-Puneet 

-----Original Message-----
From: Sudhanshu [mailto:[email-masked]] 
Sent: Thursday, April 05, 2007 9:06 AM
To: 'Jim Murphy'; [email-masked]
Cc: [email-masked]; [email-masked]; [email-masked]
Subject: Re: [Capwap] Issue 244: Preamble Header Optimization moved from

I agree, it is not a bug but an optimization. But since it related to
the data path, it should be considered as important item to address.
Moreover propose solution apply transparently to both data plane as well
control plane and make overall protocol more flexible.

Also it should address the concern of those people who wanted to make
data plane and control plane processing similar.

_Suds

-----Original Message-----
From: Jim Murphy [mailto:[email-masked]]
Sent: Wednesday, April 04, 2007 5:10 PM
To: [email-masked]
Cc: [email-masked]; [email-masked]; [email-masked]
Subject: Re: [Capwap] Issue 244: Preamble Header Optimization moved from

Thanks,

Jim

> moving issue 244 from the Wish list back into the "features" section 
> of the database, so that the WG can further discuss this issue and 
> decide what to do about it.  Issue 244 should be considered an open 
> issue against the CAPWAP drafts.
> 

> WG list.  The proposed solution was sent to the list on Jan 31, 2007 
> in this message:  
> _http://lists.frascone.com/pipermail/capwap/msg04161.html_
> 
> It does not appear that the WG made a decision on this issue either 
> way, before it was moved to the Wish list, possibly because the 
> discussion was lost inside a discussion of related issues.
> 
> The WG should consider the proposed solution for Issue 244, and 
> discuss the following alternatives on the WG list:
>

---

From: "Abhijit Choudhury (achoudhu)" <[email-masked]>
Date: Thu, 5 Apr 2007 15:12:27 -0700

Hi Dorothy,
 
We had discussed this earlier and agreed that this was a "nice to have"
and not a bug.  I recall we received very clear direction from our 
Area Director to focus on fixing real issues, and not deal with
optimizations:
http://lists.frascone.com/pipermail/capwap/msg04168.html
 
I thought that is why we had put it on our wish list.  
I'm not clear why we are opening up items that we have 
previously decided items for discussion again.
 
Thanks,
Abhijit

________________________________

From: [email-masked] [mailto:[email-masked]] 
Sent: Wednesday, April 04, 2007 11:32 AM
To: [email-masked]
Cc: [email-masked]; [email-masked]
Subject: [Capwap] Issue 244: Preamble Header Optimization moved from
WishList to Active Issues Database

Dear WG, 

<http://lists.frascone.com/pipermail/capwap/msg04161.html> 

Best Regards,

---

From: <[email-masked]>
Date: Thu, 5 Apr 2007 19:19:22 -0500

Hi Abhijit-
 
The confusion regarding this issue and the reason its being reconsidered
as an open issue is that based on the disucsssions during the interim
meeting,  the Chairs asked for this issue be discussed further on the
list.  Also during the interim its was suggested that we close new
feautures and optimizations, as David Kessens email posted after the
interim indicates.   Some members of the WG believe this issue was not
meant to go on the Wish List.   All the chairs agree that direction for
this issue and the timing of the Optimization freeze, was not clear to
the WG.  
 
Since the timing is unclear, we are revisiting this on the WG list.
We were hoping the WG membership would clearly indicate if they want to
adopt the optimization, reject the optimization or put this on the Wish
List.    Note also, that this issue is not part of the April 9th
consensus check deadline and should be considered outside the the call.
 
Do you care to voice your choice of alternatives?  This may encourage
others to do so also.   We have a few opinions, but not much to base
rough consensus on yet.
 
Best Regards,
Dorothy

	From: ext Abhijit Choudhury (achoudhu)
[mailto:[email-masked]] 
	Sent: Thursday, April 05, 2007 3:12 PM
	To: Gellert Dorothy (Nokia-SIR/MtView); [email-masked]
	Cc: [email-masked]; [email-masked]
	Subject: RE: [Capwap] Issue 244: Preamble Header Optimization
moved from WishList to Active Issues Database

	Hi Dorothy,
	 
	We had discussed this earlier and agreed that this was a "nice
to have"
	and not a bug.  I recall we received very clear direction from
our 
	Area Director to focus on fixing real issues, and not deal with
	optimizations:
	http://lists.frascone.com/pipermail/capwap/msg04168.html

	Thanks,
	Abhijit

	From: [email-masked]
[mailto:[email-masked]] 
	Sent: Wednesday, April 04, 2007 11:32 AM
	To: [email-masked]
	Cc: [email-masked]; [email-masked]
	Subject: [Capwap] Issue 244: Preamble Header Optimization moved
from WishList to Active Issues Database

	Dear WG, 

	While reviewing the recently closed issues, it appears that
Issue 244, Preamble Header Optimization, was mistakenly moved to the
Wish list without a clear decision from the WG to do so.  As a result,
we'll be moving issue 244 from the Wish list back into the "features"
section of the database, so that the WG can further discuss this issue
and decide what to do about it.  Issue 244 should be considered an open
issue against the CAPWAP drafts. 

	Issue 244 was discussed on the list under issue 224 before the
interim meeting, during the Interim meeting and again further discussed
on the WG list.  The proposed solution was sent to the list on Jan 31,
2007 in this message:
http://lists.frascone.com/pipermail/capwap/msg04161.html
<http://lists.frascone.com/pipermail/capwap/msg04161.html> 

	It does not appear that the WG made a decision on this issue
either way, before it was moved to the Wish list, possibly because the
discussion was lost inside a discussion of related issues.

	1) Adopt the proposed optimizations 
	2) Reject the proposed optimizations 
	3) Move Issue 244 to the Wish list (as this is an optimization,
not a bug fix) for future consideration. 

	Best Regards,

---

From: "Abhijit Choudhury (achoudhu)" <[email-masked]>
Date: Thu, 5 Apr 2007 19:09:06 -0700

Hi Dorothy,
 
I oppose this change because of its timing. I would support 
option 3 - to move it to the wish list.
 
At this late stage, the only changes we should be considering
are bug fixes, omissions and issues where more clarity is needed.
This is a time when we should be converging on a final spec and 
cleaning it up to send to WGLC.  This is hardly the time to be  
changing something fundamental like the data frame format for 
some minor gains.  If we want to optimize and fine 
tune, I'm sure this issue isn't the only one.  We need to keep
our eye on the schedule, otherwise we could be at this for a 
very long time.
 
Regards,
Abhijit

From: [email-masked] [mailto:[email-masked]] 
Sent: Thursday, April 05, 2007 5:19 PM
To: Abhijit Choudhury (achoudhu); [email-masked]
Cc: [email-masked]; [email-masked]
Subject: RE: [Capwap] Issue 244: Preamble Header Optimization moved from
WishList to Active Issues Database

Hi Abhijit-

 
 
Best Regards,
Dorothy

	Hi Dorothy,

	 
	Thanks,
	Abhijit

	Dear WG, 

	Best Regards,

---

From: "Pat Calhoun (pacalhou)" <[email-masked]>
Date: Fri, 6 Apr 2007 12:16:59 -0700

Jim,

I have a question about the proposal. One of the issues discussed two
IETF face to face meetings ago, was that before the version field was in
the clear, an attack could be mounted that would allow the changing of
the outer version. It is for this reason that the version field was
replicated in the capwap header, since it was protected by DTLS. 

The proposal in issue 244 suffers from the above problem.

I also presume that the "Reserved" field you show when DTLS is used
would include the actual DTLS header, correct? Or are you instead
proposing that the reserved field is optionally present, depending upon
the value of the type field.

PatC 

-----Original Message-----
From: Jim Murphy [mailto:[email-masked]] 
Sent: Wednesday, April 04, 2007 5:10 PM
To: [email-masked]
Cc: [email-masked]; [email-masked]; [email-masked]
Subject: Re: [Capwap] Issue 244: Preamble Header Optimization moved from

Thanks,

Jim

---

From: Jim Murphy <[email-masked]>
Date: Fri, 06 Apr 2007 12:32:37 -0700

For a DTLS encrypted packet the format would look like this:

         0                   1                   2                   3
         0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |Version| Type  |                    Reserved                   |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |      DTLS hdr                                                 |
        .                                                               .
        .                                                               .
        |                                                               |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |Version|  Type |  HLEN   |  RID    | WBID   |T|F|L|W|M|K|Flags |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |          Fragment ID          |     Frag Offset         |Rsvd |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                 (optional) Radio MAC Address                  |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |            (optional) Wireless Specific Information           |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                        Payload ....                           |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Which is exactly the same as the -05 draft.

For a Non-DTLS encrypted packet the format would look like this:

         0                   1                   2                   3
         0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |Version|  Type |  HLEN   |  RID    | WBID   |T|F|L|W|M|K|Flags |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |          Fragment ID          |     Frag Offset         |Rsvd |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                 (optional) Radio MAC Address                  |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |            (optional) Wireless Specific Information           |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                        Payload ....                           |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Note, in all these figures "|Version|  Type |" is replaced with
"|CAPWAP Preamble|" in the email referenced by Dorothy below.

So, no the proposal in issue 244 does not suffer from the above problem
since when DTLS is used it is exactly the same the -05 draft. The
version appears in both the shim and the encrypted CAPWAP header so
its value may be validated.

Thanks,

Jim

---

From: "Pat Calhoun (pacalhou)" <[email-masked]>
Date: Fri, 6 Apr 2007 13:13:38 -0700

OK, thanks.

While I am not a complete fan of the proposal, in the spirit of
collaboration and moving spec forward, I am willing to be supportive of
the proposed change.

PatC 

-----Original Message-----
From: Jim Murphy [mailto:[email-masked]] 
Sent: Friday, April 06, 2007 12:33 PM
To: Pat Calhoun (pacalhou)
Cc: [email-masked]; [email-masked];
[email-masked]; [email-masked]
Subject: Re: [Capwap] Issue 244: Preamble Header Optimization moved from
Wish List to Active Issues Database

         0                   1                   2                   3
 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |Version| Type  |                    Reserved
|
 
        |      DTLS hdr
|
        .
.
        .
.
        |
|
 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |Version|  Type |  HLEN   |  RID    | WBID   |T|F|L|W|M|K|Flags
|
 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |          Fragment ID          |     Frag Offset         |Rsvd
|
 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                 (optional) Radio MAC Address
|
 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |            (optional) Wireless Specific Information
|
 
        |                        Payload ....
|

         0                   1                   2                   3
 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |Version|  Type |  HLEN   |  RID    | WBID   |T|F|L|W|M|K|Flags
|
 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |          Fragment ID          |     Frag Offset         |Rsvd
|
 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                 (optional) Radio MAC Address
|
 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |            (optional) Wireless Specific Information
|
 
        |                        Payload ....
|

Note, in all these figures "|Version|  Type |" is replaced with "|CAPWAP
Preamble|" in the email referenced by Dorothy below.

So, no the proposal in issue 244 does not suffer from the above problem
since when DTLS is used it is exactly the same the -05 draft. The
version appears in both the shim and the encrypted CAPWAP header so its
value may be validated.

Thanks,

Jim

Pat Calhoun (pacalhou) wrote:
> IETF face to face meetings ago, was that before the version field was 
> in the clear, an attack could be mounted that would allow the changing

> of the outer version. It is for this reason that the version field was

> proposing that the reserved field is optionally present, depending 
> upon the value of the type field.
> 
> PatC
> 
> Subject: Re: [Capwap] Issue 244: Preamble Header Optimization moved 
> from Wish List to Active Issues Database
> 

>> interim

>> ---------------------------------------------------------------------
>> -
>> --
>>