From owner-freebsd-net@FreeBSD.ORG Tue Dec 18 06:09:07 2007 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id BA7CA16A41A for ; Tue, 18 Dec 2007 06:09:07 +0000 (UTC) (envelope-from lastewart@swin.edu.au) Received: from swin.edu.au (gpo4.cc.swin.edu.au [136.186.1.224]) by mx1.freebsd.org (Postfix) with ESMTP id 395A913C455 for ; Tue, 18 Dec 2007 06:09:05 +0000 (UTC) (envelope-from lastewart@swin.edu.au) Received: from [136.186.229.95] (lstewart.caia.swin.edu.au [136.186.229.95]) by swin.edu.au (8.13.6.20060614/8.13.1) with ESMTP id lBI4sftq018598; Tue, 18 Dec 2007 15:54:42 +1100 Message-ID: <47675291.5070101@swin.edu.au> Date: Tue, 18 Dec 2007 15:54:41 +1100 From: Lawrence Stewart User-Agent: Thunderbird 1.5.0.9 (X11/20070123) MIME-Version: 1.0 To: "freebsd-net@freebsd.org" , Iccrg@cs.ucl.ac.uk, tmrg-interest@ICSI.Berkeley.EDU, end2end-interest@postel.org Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-1.4 required=5.0 tests=ALL_TRUSTED autolearn=disabled version=3.1.9 X-Spam-Checker-Version: SpamAssassin 3.1.9 (2007-02-13) on gpo4.cc.swin.edu.au X-Mailman-Approved-At: Tue, 18 Dec 2007 12:21:44 +0000 Cc: James Healy , grenville armitage , David Malone , Randall Stewart , Fred Baker , Douglas Leith , Robert Shorten , Larry Dunn Subject: Modular/Pluggable TCP Congestion Control for FreeBSD X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Dec 2007 06:09:07 -0000 Hi all, We've been involved in a research project to implement and test an emerging TCP congestion control algorithm under FreeBSD. As a part of this, we've put together a patch for FreeBSD 7.0-BETA4 that modularises the congestion control code in the TCP stack. It allows for new congestion control algorithms to be developed as loadable kernel modules. This improves FreeBSD's usefulness as a TCP research platform and makes it easier to customise the stack for specific scenarios like high bandwidth, long delay paths. There is an accompanying technical report "Light-Weight Modular TCP Congestion Control for FreeBSD 7" [1] that covers the design, features, kernel interface and usage of the framework. Also on our website is a beta release of a module that implements the H-TCP[2] congestion control algorithm proposed by the Hamilton Institute. We believe that modular congestion control is a worthwhile addition to FreeBSD. We've performed significant internal testing and there are currently no known issues or regressions with the implementation compared to a 'vanilla' FreeBSD 7.0-BETA4 kernel. We would welcome further review and testing from the wider community in the hope of getting this patch folded into FreeBSD 8-CURRENT. SIFTR [3], our tool for monitoring FreeBSD kernel TCP connection state, has also received a minor update to v1.1.5, with the addition of 6 new, useful variables. All code and documentation is available on our website[3]. Cheers, Jim and Lawrence http://caia.swin.edu.au [1] http://caia.swin.edu.au/reports/071218A/CAIA-TR-071218A.pdf [2] http://www.hamilton.ie/net/htcp3.pdf [3] http://caia.swin.edu.au/urp/newtcp/tools.html