From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-12-ewr.dyndns.com (mxout-055-ewr.mailhop.org [216.146.33.55]) by lists.bufferbloat.net (Postfix) with ESMTP id 6BFE72E04AC for ; Tue, 8 Feb 2011 11:57:01 -0800 (PST) Received: from scan-12-ewr.mailhop.org (scan-12-ewr.local [10.0.141.230]) by mail-12-ewr.dyndns.com (Postfix) with ESMTP id 02F5393545D for ; Tue, 8 Feb 2011 19:57:00 +0000 (UTC) X-Spam-Score: 0.0 () X-Mail-Handler: MailHop by DynDNS X-Originating-IP: 134.157.0.129 Received: from shiva.jussieu.fr (shiva.jussieu.fr [134.157.0.129]) by mail-12-ewr.dyndns.com (Postfix) with ESMTP id 7529E9353E0 for ; Tue, 8 Feb 2011 19:56:59 +0000 (UTC) Received: from hydrogene.pps.jussieu.fr (hydrogene.pps.jussieu.fr [134.157.168.1]) by shiva.jussieu.fr (8.14.4/jtpda-5.4) with ESMTP id p18JuUjj076253 ; Tue, 8 Feb 2011 20:56:43 +0100 (CET) X-Ids: 165 Received: from lanthane.pps.jussieu.fr (lanthane.pps.jussieu.fr [134.157.168.57]) by hydrogene.pps.jussieu.fr (8.13.4/jtpda-5.4) with ESMTP id p18JuRCC022912 ; Tue, 8 Feb 2011 20:56:29 +0100 Received: from jch by lanthane.pps.jussieu.fr with local (Exim 4.72) (envelope-from ) id 1Pmtfn-0004Yx-6E; Tue, 08 Feb 2011 20:56:27 +0100 From: Juliusz Chroboczek To: d@taht.net (Dave =?iso-8859-1?Q?T=E4ht?=) References: <87oc6pf4bc.fsf@cruithne.co.teklibre.org> Date: Tue, 08 Feb 2011 20:56:27 +0100 In-Reply-To: <87oc6pf4bc.fsf@cruithne.co.teklibre.org> ("Dave =?iso-8859-1?Q?T=E4ht=22's?= message of "Sun, 06 Feb 2011 10:41:59 -0700") Message-ID: <7ihbcecnbo.fsf@lanthane.pps.jussieu.fr> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Miltered: at jchkmail.jussieu.fr with ID 4D519FEE.002 by Joe's j-chkmail (http : // j-chkmail dot ensmp dot fr)! X-j-chkmail-Enveloppe: 4D519FEE.002/134.157.168.1/hydrogene.pps.jussieu.fr/hydrogene.pps.jussieu.fr/ Cc: bloat Subject: Re: [Bloat] The wireless problem in a nutshell X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Feb 2011 19:57:01 -0000 > what you are also doing is dividing the TCP streams into two pieces - > the wireless piece is VERY short - and congestion control then works > correctly using existing techniques on the wired and unwired portions > of the connection. You've reinvented a useful technique, called "split-TCP". It's commonly used by the "WAN accelerators" that you can buy in order to get Microsoft protocols working across the Internet. The downside of split-TCP, of course, is that it breaks e2e, and hence fate sharing, i.e. it introduces a new point of failure and makes your network more brittle. The challenge is to make TCP efficient without the need for split-TCP, which requires differentiating between congestion-induced loss and wireless loss. --Juliusz