Re: [Tsvwg] HS-TCP/FAST-TCP: Kind of Packet Loss?

Sally Floyd <floyd@icir.org> Wed, 23 July 2003 21:17 UTC

Received: from optimus.ietf.org (ietf.org [132.151.1.19] (may be forged)) by ietf.org (8.9.1a/8.9.1a) with ESMTP id RAA03169 for <tsvwg-archive@odin.ietf.org>; Wed, 23 Jul 2003 17:17:29 -0400 (EDT)
Received: from localhost.localdomain ([127.0.0.1] helo=www1.ietf.org) by optimus.ietf.org with esmtp (Exim 4.20) id 19fQys-0007Uw-OU for tsvwg-archive@odin.ietf.org; Wed, 23 Jul 2003 17:17:02 -0400
Received: (from exim@localhost) by www1.ietf.org (8.12.8/8.12.8/Submit) id h6NLH2m7028787 for tsvwg-archive@odin.ietf.org; Wed, 23 Jul 2003 17:17:02 -0400
Received: from localhost.localdomain ([127.0.0.1] helo=www1.ietf.org) by optimus.ietf.org with esmtp (Exim 4.20) id 19fQyr-0007TZ-GK; Wed, 23 Jul 2003 17:17:01 -0400
Received: from odin.ietf.org ([132.151.1.176] helo=ietf.org) by optimus.ietf.org with esmtp (Exim 4.20) id 19fQyp-0007TO-OE for tsvwg@optimus.ietf.org; Wed, 23 Jul 2003 17:16:59 -0400
Received: from ietf-mx (ietf-mx.ietf.org [132.151.6.1]) by ietf.org (8.9.1a/8.9.1a) with ESMTP id RAA03163 for <tsvwg@ietf.org>; Wed, 23 Jul 2003 17:16:55 -0400 (EDT)
Received: from ietf-mx ([132.151.6.1]) by ietf-mx with esmtp (Exim 4.12) id 19fQyn-0000tG-00 for tsvwg@ietf.org; Wed, 23 Jul 2003 17:16:57 -0400
Received: from cougar.icir.org ([192.150.187.76]) by ietf-mx with esmtp (Exim 4.12) id 19fQyX-0000t2-00 for tsvwg@ietf.org; Wed, 23 Jul 2003 17:16:41 -0400
Received: from cougar.icir.org (localhost [127.0.0.1]) by cougar.icir.org (8.12.8p1/8.12.3) with ESMTP id h6NLGGe3008199; Wed, 23 Jul 2003 14:16:16 -0700 (PDT) (envelope-from floyd@cougar.icir.org)
Message-Id: <200307232116.h6NLGGe3008199@cougar.icir.org>
To: John Heffner <jheffner@psc.edu>
cc: tsvwg@ietf.org
From: Sally Floyd <floyd@icir.org>
Subject: Re: [Tsvwg] HS-TCP/FAST-TCP: Kind of Packet Loss?
Date: Wed, 23 Jul 2003 14:16:16 -0700
Sender: tsvwg-admin@ietf.org
Errors-To: tsvwg-admin@ietf.org
X-BeenThere: tsvwg@ietf.org
X-Mailman-Version: 2.0.12
Precedence: bulk
List-Unsubscribe: <https://www1.ietf.org/mailman/listinfo/tsvwg>, <mailto:tsvwg-request@ietf.org?subject=unsubscribe>
List-Id: Transport Area Working Group <tsvwg.ietf.org>
List-Post: <mailto:tsvwg@ietf.org>
List-Help: <mailto:tsvwg-request@ietf.org?subject=help>
List-Subscribe: <https://www1.ietf.org/mailman/listinfo/tsvwg>, <mailto:tsvwg-request@ietf.org?subject=subscribe>

>I think packet corruption is not currently the greatest problem.  There
>are a number of other causes of packet loss, including:
>  - intermittent flows starting up (punching holes with slow-start)
>  - misbehaving switches
>  - burstiness, and a small router buffer
>
>When these things cause cwnd to be halved on the order of once every few
>minutes, they can seriously degrade the performance of high-BDP flows.  A
>faster response time can really help, and I think is ultimately necessary
>if we expect end-to-end congestion control to work in messy networks at
>large window sizes.

Yep!  I agree that packet corruption is not the motivating problem here.

- Sally


_______________________________________________
tsvwg mailing list
tsvwg@ietf.org
https://www1.ietf.org/mailman/listinfo/tsvwg