From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-13-ewr.dyndns.com (mxout-138-ewr.mailhop.org [216.146.33.138]) by lists.bufferbloat.net (Postfix) with ESMTP id 1A5F32E044B for ; Fri, 4 Feb 2011 01:36:21 -0800 (PST) Received: from scan-11-ewr.mailhop.org (scan-11-ewr.local [10.0.141.229]) by mail-13-ewr.dyndns.com (Postfix) with ESMTP id 4FADEA4C022 for ; Fri, 4 Feb 2011 09:36:20 +0000 (UTC) X-Spam-Score: 0.0 () X-Mail-Handler: MailHop by DynDNS X-Originating-IP: 213.186.56.95 Received: from witko.kerneis.info (witko.kerneis.info [213.186.56.95]) by mail-13-ewr.dyndns.com (Postfix) with ESMTP id 17053A4BE7F for ; Fri, 4 Feb 2011 09:36:16 +0000 (UTC) Received: from bob75-11-78-249-231-16.fbx.proxad.net ([78.249.231.16] helo=trurl.pps.jussieu.fr) by witko.kerneis.info with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.72) (envelope-from ) id 1PlI5O-0007zw-Um for bloat@lists.bufferbloat.net; Fri, 04 Feb 2011 10:36:15 +0100 Received: from jch by trurl.pps.jussieu.fr with local (Exim 4.72) (envelope-from ) id 1PlI5E-0000d3-2d for bloat@lists.bufferbloat.net; Fri, 04 Feb 2011 10:36:04 +0100 From: Juliusz Chroboczek To: bloat@lists.bufferbloat.net Date: Fri, 04 Feb 2011 10:36:02 +0100 Message-ID: <87mxmcdtvh.fsf@trurl.pps.jussieu.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 78.249.231.16 X-SA-Exim-Mail-From: jch@pps.jussieu.fr X-SA-Exim-Scanned: No (on witko.kerneis.info); SAEximRunCond expanded to false Subject: [Bloat] =?iso-8859-1?q?About_LEDBAT=2C_=B5TP_and_BitTorrent?= 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, 04 Feb 2011 09:36:22 -0000 Hi, In his series of articles, Jim has mostly been concerned about router-based solutions to the delay issues. As you know, people have also been working on end-to-end solutions, mostly within the framework of TCP (people have already mentioned TCP-Vegas on this list). There's a couple things I'd like to add. Linux allows switching congeston controllers on the fly. I've used this in the Transmssion BitTorrent client, which is now able to use TCP-LP (a less aggressive variant of Vegas) on a system that uses the default congestion controller for other TCP connexions [1]. Of particular notice is the LEDBAT congestion controller [2], which, to my knowledge, is the only congestion controller that was explicitly designed to bound delay [3]. It is also the only delay-besed controller that has been deployed on a massive scale -- all recent versions of µTorrent use LEDBAT by default. If you'd like to experiment with LEDBAT under Linux, I've recently ported the µTorrent code to Transmission [4], and I'm told it's also in KTorrent and libtorrent. I'd love to see LEDBAT in the Linux kernel, and I know people who'd love to see it in Windows. If you'd like to either do the work or fund it, please do get in touch. --Juliusz [1] http://www.pps.jussieu.fr/~jch/software/bittorrent/tcp-congestion-control.html [2] http://datatracker.ietf.org/wg/ledbat/charter/ [3] http://forum.bittorrent.org/viewtopic.php?pid=762#p762 [4] https://forum.transmissionbt.com/viewtopic.php?f=1&t=11130