Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

Re: [8023-CMTF] 802.3ar/D0.9 is available



Kevin,
 
Thanks for the timely response and clarification. I see from the official stated objectives
I was mistaken.
 
I had incorrectly assumed (via informal discussions in the past) that an objective was
to eliminate congestion-related frame drops. The observations were that frame drops
on 802.3 were the primary (and possibly only) reason for using FibreChannel and/or
Infiniband rather than 802.3 links. And, many of the frame drops could be associated
with transient overload conditions.
 
I happened to agree with this informal objective and believed it could be done, without
undue complexity, if the scope was limited to computer-room communications, where
the link distance (measured in time) is less than an MTU.
 
From your email, I assume this is not an official objective, and certainly not the
primary objective. While that will no doubt allow the group to converge quickly,
I'm disappointed that (what I feel is) the most valuable objective will not be met.
 
Since avoiding frame loss (via credits, busy-retry, etc.) is a bit inconsistent with
Ethernet philosophies, this may not be the right area to accomplish this objective.
Perhaps this is better done in other arena, where more backplane designers are
present and/or available for consultation.
 
Respectfully,
DVJ
 
 

From: Kevin Daines [mailto:Kevin.Daines@wwp.com]
Sent: Tuesday, October 25, 2005 11:36 PM
To: David V James; STDS-802-3-CM@listserv.ieee.org
Subject: RE: [8023-CMTF] 802.3ar/D0.9 is available

David,
 
Not sure what you mean by "primary objective". Perhaps you didn't intend to use the "reserved word" objective. The following are the (4) TF objectives:
 
1) Specify a mechanism to limit the rate of transmitted data on an Ethernet link
2)
Specify a mechanism to support the communication of congestion information
3) Preserve the MAC/PLS service interfaces
4) Minimize throughput reduction in non-congested flows
 
The CMTF adopted a proposal to satisfy CMTF objective #1.
 
Recently, proposals related to (backward) congestion notification have been made in 802.1 (related to #2).
 
 
 
Kevin Daines
Chair, P802.3ar TF


From: David V James [mailto:dvj@alum.mit.edu]
Sent: Tuesday, October 25, 2005 11:04 PM
To: Kevin Daines; STDS-802-3-CM@listserv.ieee.org
Subject: RE: [8023-CMTF] 802.3ar/D0.9 is available

Kevin,
 
I would claim that the TF has still not provided any promising
solutions for avoiding dropped frames in a short-distance
(computer room) environment.
 
Thus, since it doesn't currently meet its primary objective,
I would smile (rather than frown) at radical new ideas that
have a chance of meeting the primary objective.
 
DVJ

 
-----Original Message-----
From: Kevin Daines [mailto:Kevin.Daines@WWP.COM]
Sent: Tuesday, October 25, 2005 5:20 PM
To: STDS-802-3-CM@listserv.ieee.org
Subject: Re: [8023-CMTF] 802.3ar/D0.9 is available

Asif,
 
As with any TF meeting pre-D1.0, presentations in support of or related to the TF objectives are welcome and encouraged. Post-D1.0, the TF naturally shifts its focus to perfecting the draft. During that phase, radically new ideas are generally frowned upon.
 
That said, the plans for the meeting are
 
1) Review D0.9 and prepare D1.0. Since we have adopted one proposal in support of one of our objectives, it is the first order of business.
2) Entertain presentations, if any, in support of or related to the TF objectives.  I'll send my customary "Call for presentations" e-mail shortly.
 
Kevin Daines
Chair, P802.3ar TF


From: Asif Hazarika [mailto:ahazarik@FMA.FUJITSU.COM]
Sent: Tuesday, October 25, 2005 5:10 PM
To: STDS-802-3-CM@listserv.ieee.org
Subject: Re: [8023-CMTF] 802.3ar/D0.9 is available

Kevin,
 
Hello. Time to discuss about the plans for the  plenary meeting.
What are the plans? We would like to meet and discuss the draft and get updates.
 
regards
asif
 
-----Original Message-----
From: Kevin Daines [mailto:Kevin.Daines@WWP.COM]
Sent: Tuesday, October 25, 2005 3:51 PM
To: STDS-802-3-CM@listserv.ieee.org
Subject: [8023-CMTF] 802.3ar/D0.9 is available

Congestion Management TF members,
 
At the July 2005 IEEE 802 Plenary meeting in San Francisco, we (the P802.3ar CMTF) passed the following motion:
 
"Adopt changes to Clause 4, Annex 4A & Clause 30 described in barrass_1_0505.pdf as a baseline proposal for 802.3ar/D1.0. The changes to Clause 4 will be made after the
changes to Annex 4A have been solidified in 802.3ar TF review."
 
In order to jumpstart our progress on D1.0, Hugh Barrass and I have prepared P802.3ar/D0.9 for CMTF preview. It may be found here:
 
http://www.ieee802.org/3/ar/public/0511/802.3ar-d0_9.pdf
 
Please note this draft has no official status. It is being made available for TF preview, prior to the November meeting, in order to more efficiently prepare P802.3ar/D1.0 and commence TF ballot after we meet in November. Hope to see you in Vancouver.
 
 
Kevin Daines
Chair, P802.3ar CMTF