From owner-freebsd-stable@FreeBSD.ORG Sat Jan 27 09:57:53 2007 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 94D2C16A400 for ; Sat, 27 Jan 2007 09:57:53 +0000 (UTC) (envelope-from bms@FreeBSD.org) Received: from out4.smtp.messagingengine.com (out4.smtp.messagingengine.com [66.111.4.28]) by mx1.freebsd.org (Postfix) with ESMTP id 6C4AF13C46B for ; Sat, 27 Jan 2007 09:57:53 +0000 (UTC) (envelope-from bms@FreeBSD.org) Received: from out1.internal (unknown [10.202.2.149]) by out1.messagingengine.com (Postfix) with ESMTP id 388EA993E4; Sat, 27 Jan 2007 04:57:53 -0500 (EST) Received: from heartbeat1.messagingengine.com ([10.202.2.160]) by out1.internal (MEProxy); Sat, 27 Jan 2007 04:57:53 -0500 X-Sasl-enc: ufNJq6Ax3CdRifNwmDvvnLqR4et7AhBlV5wG/LzFAo7B 1169891872 Received: from [192.168.123.18] (82-35-112-254.cable.ubr07.dals.blueyonder.co.uk [82.35.112.254]) by mail.messagingengine.com (Postfix) with ESMTP id 25BD6146D9; Sat, 27 Jan 2007 04:57:50 -0500 (EST) Message-ID: <45BB221D.3050508@FreeBSD.org> Date: Sat, 27 Jan 2007 09:57:49 +0000 From: "Bruce M. Simpson" User-Agent: Thunderbird 1.5.0.9 (X11/20070125) MIME-Version: 1.0 To: Luigi Rizzo References: <53B52415C756A84E8A169F0E3673A3290E8BA4@IMCSRV6.MITRE.ORG> <20070124071021.GG874@turion.vk2pj.dyndns.org> <20070124073602.B57678@xorpc.icir.org> In-Reply-To: <20070124073602.B57678@xorpc.icir.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-stable@freebsd.org Subject: Re: Dummynet and simulating random delay X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 27 Jan 2007 09:57:53 -0000 Luigi Rizzo wrote: > On Wed, Jan 24, 2007 at 06:10:21PM +1100, Peter Jeremy wrote: > >> On Tue, 2007-Jan-23 14:22:54 -0500, Andresen, Jason R. wrote: >> >>> I have a project that requires me to simulate a link with varying but >>> well defined delay. The link is guarenteed to deliver packets in >>> order, so I wish to maintain that behavior with Dummynet. >>> >> I don't think dummynet can do this in its current form. Based on >> > > actually dummynet never does reordering within a single pipe, even > if you change the delay on the fly. > > But this said, you should explain "varying but well defined delay", > Hitting up Google reveals someone hacked Dummynet to introduce per-flow randomness in a uniform distribution: http://www.cs.unc.edu/~jeffay/dirt/FAQ/dummynet-modifications.html However, they included entire source files against FreeBSD 4.5; forward-porting should hopefully not be too tedious for an interested party. Regards, BMS