From owner-freebsd-net@FreeBSD.ORG Thu Oct 11 14:34:58 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 CBAF016A419 for ; Thu, 11 Oct 2007 14:34:58 +0000 (UTC) (envelope-from bh@izb.knu.ac.kr) Received: from izb.knu.ac.kr (unknown [IPv6:2002:9be6:9d5d:1::1]) by mx1.freebsd.org (Postfix) with ESMTP id 453D213C44B for ; Thu, 11 Oct 2007 14:34:57 +0000 (UTC) (envelope-from bh@izb.knu.ac.kr) Received: by draba.izb.knu.ac.kr (Postfix, from userid 59) id 75ECE3EA5; Thu, 11 Oct 2007 23:34:55 +0900 (KST) X-Spam-Checker-Version: SpamAssassin 3.2.3 (2007-08-08) on draba.izb.knu.ac.kr X-Spam-Level: X-Spam-Status: No, score=-46.7 required=15.1 tests=ALL_TRUSTED,DKIM_SIGNED, DKIM_VERIFIED autolearn=disabled version=3.2.3 X-Spam-DKIM-Comments: Signing and Verifying with Mail-DKIM and DKIM Proxy ; DKIM? See http://www.google.com/search?btnI&q=DomainKeys+Identified+Mail Received: from izb.knu.ac.kr (localhost.izb.knu.ac.kr [127.0.0.1]) by draba.izb.knu.ac.kr (Postfix) with ESMTP id A49B33EA4; Thu, 11 Oct 2007 23:34:53 +0900 (KST) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=izb.knu.ac.kr; h=subject: from:reply-to:to:cc:in-reply-to:references:content-type: content-transfer-encoding:date:message-id:mime-version; q= dns/txt; s=s1024; bh=VqCypxjshnMTKK9I6dyJQNjQyFc=; b=Ectf+jXBtxQ YsVISZ+5twQwgxwDMM08QSnBvH0NAw43X+2XWlttM+g+NuPqf9Ctst/LKTojJUGw sukhLbTrSJ4CKdjiE8v8IbI1/l+GvOKGebLzIbvpvtTIbKyAmTY5FspNFGMdY//q mVC/s1pVAhpyNJiXwxu4LltecbBvbWGk= Received: from viola.izb.knu.ac.kr (viola.izb.knu.ac.kr [IPv6:2002:9be6:9d5d:3::3]) by draba.izb.knu.ac.kr (Postfix) with ESMTP id 8D1AA3EA3; Thu, 11 Oct 2007 23:34:53 +0900 (KST) Received: by viola.izb.knu.ac.kr (Postfix, from userid 1001) id C2ABE5DFF; Thu, 11 Oct 2007 23:34:53 +0900 (KST) From: Byung-Hee HWANG To: Lawrence Stewart In-Reply-To: <470D88E2.5070707@room52.net> References: <470C2DFD.20109@room52.net> <1192006616.6441.16.camel@viola.izb.knu.ac.kr> <470D88E2.5070707@room52.net> Content-Type: text/plain Content-Transfer-Encoding: 7bit Organization: InZealBomb Date: Thu, 11 Oct 2007 23:34:53 +0900 Message-Id: <1192113293.8383.15.camel@viola.izb.knu.ac.kr> Mime-Version: 1.0 X-Mailer: Evolution 2.8.1.1 FreeBSD GNOME Team Port Cc: James Healy , freebsd-net@freebsd.org Subject: Re: Software for FreeBSD TCP R&D: SIFTR v1.1.4 and DPD v1.0 released X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: bh@izb.knu.ac.kr List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Oct 2007 14:34:58 -0000 On Thu, 2007-10-11 at 12:22 +1000, Lawrence Stewart wrote: > Hi Byung-Hee, > > Byung-Hee HWANG wrote: > > On Wed, 2007-10-10 at 11:42 +1000, Lawrence Stewart wrote: > > > >> Hi All, > >> > >> Just a quick heads up regarding the availability of a new SIFTR > >> (Statistical Information for TCP Research) version and the debut release > >> of DPD (Deterministic Packet Discard). > >> > >> SIFTR v1.1.4 addresses a couple of issues, one of which is applicable to > >> users of SIFTR in FreeBSD 7-CURRENT. Read the changelog and readme for > >> more information. > >> > >> DPD is a new FreeBSD kernel module we developed to further aid us in our > >> ongoing TCP research. It allows for the deterministic dropping of TCP > >> packets from within the FreeBSD kernel via a simple sysctl interface. > >> This is particularly useful for anyone that is interested in observing > >> TCP reacting to packet loss events (e.g. congestion control > >> researchers). Being able to drop the same packet(s) across multiple > >> tests allows for simpler comparisons of TCP behaviour. We've found it > >> particularly useful in evaluating and observing the behaviour of > >> different congestion control mechanisms, and hope it may be of use to > >> others out there. Please refer to the DPD readme for more in-depth > >> information. > >> > >> The software and documentation is freely available under a BSD licence from: > >> > >> http://caia.swin.edu.au/urp/newtcp/tools.html > >> > >> We would be very happy to hear from anyone regarding bugs and > >> suggestions as well. > >> > > > > First of all, I would like to thank you for your good efforts. Its > > almost feature seems like PF(4), however, it's useful to me, maybe. > > > > Thanks! > > w.r.t. PF, as far as I'm aware, it does not allow the user to drop > arbitrary packets identified by number within a TCP flow. Dummynet with > its uniform packet loss pipe configuration is about the closest thing to > DPD that I know of. The problem with Dummynet's uniform packet loss is > that you have no control over which packets get dropped, which makes > analysing TCP behaviour very difficult indeed. That said, I could simply > be blissfully unaware that such functionality exists in PF. > > > Are you willing to support IPv6 for both SIFTR and DPD? > > > In the short term, our research does not entail the use of IPv6 and > there is currently insufficient time available for implementing > functionality that is not immediately useful to us. > > That said, it should be fairly straight-forward work to add IPv6 > support, and I'd be more than happy to give you all the pointers and > tips required to carry out the modifications if you were so inclined. I don't want that my comment can force your thinking for implementing. IPv6 support, it was just my wish list for your software. So never mind. And if I encounter strange problems, then I'll give you email;; Thanks, -- Byung-Hee HWANG "Michael, it's not true, please say it's not true." -- Kay Adams, "Chapter 31", page 434