From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-31-ewr.dyndns.com (mxout-126-ewr.mailhop.org [216.146.33.126]) by lists.bufferbloat.net (Postfix) with ESMTP id D41F22E018E for ; Thu, 17 Mar 2011 22:51:59 -0700 (PDT) Received: from scan-31-ewr.mailhop.org (scan-31-ewr.local [10.0.141.237]) by mail-31-ewr.dyndns.com (Postfix) with ESMTP id 325256F80FA for ; Fri, 18 Mar 2011 05:51:59 +0000 (UTC) X-Spam-Score: -1.0 (-) X-Mail-Handler: MailHop by DynDNS X-Originating-IP: 74.125.82.171 Received: from mail-wy0-f171.google.com (mail-wy0-f171.google.com [74.125.82.171]) by mail-31-ewr.dyndns.com (Postfix) with ESMTP id 5806F6F72F5 for ; Fri, 18 Mar 2011 05:51:54 +0000 (UTC) Received: by wyb32 with SMTP id 32so4200698wyb.16 for ; Thu, 17 Mar 2011 22:51:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:subject:from:to:cc:in-reply-to:references :content-type:date:message-id:mime-version:x-mailer :content-transfer-encoding; bh=se+DO06evWkA83OPT8PrZiMk/JxPhUPOCVEscRRrhVs=; b=FO7jMuSuDnQod3gBG0eSuq65uD1633EIiQ1V2JsAK2gPza09/iFZdyZIT9aYiwMOJB UkDHu8TRN1ET08bqIktagJRL/PP6I36DhiNDhOxqL2sY900Zz0Gq52nc3wwnHlRUcdcD CWe2MoJkgFjSy6L6uqn7VyqIpTGramoL2eBBc= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=EH+3MC6ga2bHkhF3wf7dLIPTpmxnItp6YFAk1Gg+0QWAQ2dJuza83kStt6LPCz/jhO WsFVAzQZl7Dx3if1okFiehJ1QedPVnW2/M86bJvmBFdirFlaw2zEmbNUh07Vp0ZTaQyQ ZLePc96PZ/d9wf6yh6SfGknDT7iYDVjrBEXy0= Received: by 10.216.142.221 with SMTP id i71mr661972wej.93.1300427513696; Thu, 17 Mar 2011 22:51:53 -0700 (PDT) Received: from [10.150.51.211] (gw0.net.jmsp.net [212.23.165.14]) by mx.google.com with ESMTPS id f30sm1407651wef.7.2011.03.17.22.51.51 (version=SSLv3 cipher=OTHER); Thu, 17 Mar 2011 22:51:52 -0700 (PDT) From: Eric Dumazet To: rick.jones2@hp.com In-Reply-To: <1300400436.2087.2401.camel@tardy> References: <4D7F4121.40307@freedesktop.org> <20110315175942.GA10064@goldfish> <1300212877.2087.2155.camel@tardy> <20110315183111.GB2542@tuxdriver.com> <29B06777-CC5F-4802-8727-B04F58CDA9E3@gmail.com> <20110315205146.GF2542@tuxdriver.com> <219C7840-ED79-49EA-929D-96C5A6200401@gmail.com> <20110316004722.GD28663@tuxdriver.com> <66469263-763A-4D5A-B689-026D0603C170@gmail.com> <1300386132.2087.2345.camel@tardy> <44F5E713-4AB2-4D34-9DD5-97FBE92E401F@gmail.com> <1300400436.2087.2401.camel@tardy> Content-Type: text/plain; charset="UTF-8" Date: Fri, 18 Mar 2011 06:51:48 +0100 Message-ID: <1300427508.2881.2.camel@edumazet-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 8bit Cc: bloat@lists.bufferbloat.net Subject: Re: [Bloat] Random idea in reaction to all the discussion of TCP flavours - timestamps? 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: Fri, 18 Mar 2011 05:52:00 -0000 Le jeudi 17 mars 2011 à 15:20 -0700, Rick Jones a écrit : > I would think that unless the rest of the segments of the connection > will also bypass most of the traffic, the SYN or SYN|ACK should not > bypass - to do so will give the TCP connection a low, unrealistic > initial estimate of the RTT. Given the recent change in Linux upstream > to go to cwnd_init of 10 segments, and the prospect of other stacks > following that lead in implementing the draft RFC, if there is a big > slow queue of traffic that the data segments will not bypass, it would > seem better to have the SYN or SYN|ACK get delayed and retransmitted to > get the cwnd down. > > SYN and SYN|ACK segments should not receive special treatment beyond > what data segments for the same connection would get. Agreed. RFC 3168 (The Addition of Explicit Congestion Notification (ECN) to IP) discuss of this topic, and goes further : SYN packets, or retransmitted packets dont have ECT marker : They have higher probabilities to be dropped by ECN routers than marked and pass the congestion point.