Re: HTTP/2 and TCP CWND

Wesley Eddy <wes@mti-systems.com> Wed, 17 April 2013 16:50 UTC

Return-Path: <ietf-http-wg-request@listhub.w3.org>
X-Original-To: ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com
Delivered-To: ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id B714D21F8AA8 for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Wed, 17 Apr 2013 09:50:37 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -10.599
X-Spam-Level:
X-Spam-Status: No, score=-10.599 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, RCVD_IN_DNSWL_HI=-8]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 05ktR-lvSY42 for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Wed, 17 Apr 2013 09:50:37 -0700 (PDT)
Received: from frink.w3.org (frink.w3.org [128.30.52.56]) by ietfa.amsl.com (Postfix) with ESMTP id 320B821F8A8A for <httpbisa-archive-bis2Juki@lists.ietf.org>; Wed, 17 Apr 2013 09:50:37 -0700 (PDT)
Received: from lists by frink.w3.org with local (Exim 4.72) (envelope-from <ietf-http-wg-request@listhub.w3.org>) id 1USVXt-0002OW-07 for ietf-http-wg-dist@listhub.w3.org; Wed, 17 Apr 2013 16:49:21 +0000
Resent-Date: Wed, 17 Apr 2013 16:49:21 +0000
Resent-Message-Id: <E1USVXt-0002OW-07@frink.w3.org>
Received: from maggie.w3.org ([128.30.52.39]) by frink.w3.org with esmtp (Exim 4.72) (envelope-from <wes@mti-systems.com>) id 1USVXq-0002Nr-BN for ietf-http-wg@listhub.w3.org; Wed, 17 Apr 2013 16:49:18 +0000
Received: from atl4mhob06.myregisteredsite.com ([209.17.115.44]) by maggie.w3.org with esmtp (Exim 4.72) (envelope-from <wes@mti-systems.com>) id 1USVXo-0000DZ-Gw for ietf-http-wg@w3.org; Wed, 17 Apr 2013 16:49:18 +0000
Received: from mail.hostingplatform.com ([10.30.71.204]) by atl4mhob06.myregisteredsite.com (8.14.4/8.14.4) with ESMTP id r3HGmtUm006395 for <ietf-http-wg@w3.org>; Wed, 17 Apr 2013 12:48:55 -0400
Received: (qmail 14424 invoked by uid 0); 17 Apr 2013 16:48:55 -0000
Received: from unknown (HELO ?192.168.1.100?) (wes@mti-systems.com@69.81.143.143) by 0 with ESMTPA; 17 Apr 2013 16:48:55 -0000
Message-ID: <516ED26E.5010608@mti-systems.com>
Date: Wed, 17 Apr 2013 12:48:46 -0400
From: Wesley Eddy <wes@mti-systems.com>
Organization: MTI Systems
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130328 Thunderbird/17.0.5
MIME-Version: 1.0
To: Eliot Lear <lear@cisco.com>
CC: Patrick McManus <mcmanus@ducksong.com>, Gabriel Montenegro <Gabriel.Montenegro@microsoft.com>, Roberto Peon <grmocg@gmail.com>, "Simpson, Robby (GE Energy Management)" <robby.simpson@ge.com>, Robert Collins <robertc@squid-cache.org>, Jitu Padhye <padhye@microsoft.com>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>, "Brian Raymor (MS OPEN TECH)" <Brian.Raymor@microsoft.com>, Rob Trace <Rob.Trace@microsoft.com>, Dave Thaler <dthaler@microsoft.com>, Martin Thomson <martin.thomson@skype.net>, "Eggert, Lars" <lars@netapp.com>, Martin Stiemerling <martin.stiemerling@neclab.eu>
References: <516B8824.8040904@cisco.com> <DF8F6DB7E5D58B408041AE4D927B2F48CBB88103@CINURCNA14.e2k.ad.ge.com> <CAP+FsNfeUtKfOMPKriYP7Ak_YzsjEFKvprJOAQaxYP7_BxTBsw@mail.gmail.com> <cf53405c48dc431693573a9148776c8a@BN1PR03MB072.namprd03.prod.outlook.com> <CAOdDvNpidZwfMS_y_Hy56UjOaD9uNi-s=B9MErQSq4Msd3oBKw@mail.gmail.com> <516D51BE.1080402@cisco.com>
In-Reply-To: <516D51BE.1080402@cisco.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Received-SPF: none client-ip=209.17.115.44; envelope-from=wes@mti-systems.com; helo=atl4mhob06.myregisteredsite.com
X-W3C-Hub-Spam-Status: No, score=0.0
X-W3C-Hub-Spam-Report: RCVD_IN_DNSWL_NONE=-0.0001
X-W3C-Scan-Sig: maggie.w3.org 1USVXo-0000DZ-Gw 6b476a31cc834cda316021c4b03853e6
X-Original-To: ietf-http-wg@w3.org
Subject: Re: HTTP/2 and TCP CWND
Archived-At: <http://www.w3.org/mid/516ED26E.5010608@mti-systems.com>
Resent-From: ietf-http-wg@w3.org
X-Mailing-List: <ietf-http-wg@w3.org> archive/latest/17290
X-Loop: ietf-http-wg@w3.org
Resent-Sender: ietf-http-wg-request@w3.org
Precedence: list
List-Id: <ietf-http-wg.w3.org>
List-Help: <http://www.w3.org/Mail/>
List-Post: <mailto:ietf-http-wg@w3.org>
List-Unsubscribe: <mailto:ietf-http-wg-request@w3.org?subject=unsubscribe>

On 4/16/2013 9:27 AM, Eliot Lear wrote:
> 
> On 4/16/13 3:45 AM, Patrick McManus wrote:
> 
>> Part of what you inject is traditional L4 information (what was our
>> CWND before) which is much more interesting than a constant,
> 
> Much more interesting.  That much we agree on.  Whether it is
> information or misinformation is the real question.
> 


It's definitely misinformation given the dynamic nature of the
CWND variable in TCP.  This is not a path property like MTU that
can be thought of as relatively static, and it can change on short
timescales with high granularity.


-- 
Wes Eddy
MTI Systems