From owner-freebsd-net@FreeBSD.ORG Fri Jul 29 01:32:24 2005 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id D867F16A420 for ; Fri, 29 Jul 2005 01:32:24 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from pi.codefab.com (pi.codefab.com [199.103.21.227]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2B77A43D49 for ; Fri, 29 Jul 2005 01:32:24 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from localhost (localhost [127.0.0.1]) by pi.codefab.com (Postfix) with ESMTP id 464225E1E; Thu, 28 Jul 2005 21:32:21 -0400 (EDT) Received: from pi.codefab.com ([127.0.0.1]) by localhost (pi.codefab.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 61571-10; Thu, 28 Jul 2005 21:32:19 -0400 (EDT) Received: from [192.168.1.3] (pool-68-161-54-113.ny325.east.verizon.net [68.161.54.113]) by pi.codefab.com (Postfix) with ESMTP id E78FE5DEC; Thu, 28 Jul 2005 21:32:18 -0400 (EDT) Message-ID: <42E98725.1020600@mac.com> Date: Thu, 28 Jul 2005 21:32:21 -0400 From: Chuck Swiger Organization: The Courts of Chaos User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.8) Gecko/20050511 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Daniel O'Connor References: <200507290834.10268.doconnor@gsoft.com.au> <42E97AF1.9060104@elischer.org> <200507291035.46770.doconnor@gsoft.com.au> In-Reply-To: <200507291035.46770.doconnor@gsoft.com.au> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: amavisd-new at codefab.com Cc: freebsd-net@freebsd.org, julian@elischer.org Subject: Re: AltQ + ng_iface 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: Fri, 29 Jul 2005 01:32:25 -0000 Daniel O'Connor wrote: > On Friday 29 July 2005 10:10, Julian Elischer wrote: [ ... ] >>ipfw and dummynet work on ng_iface I believe. > > Well yeah, but dummynet is a little inflexible and can't prioritise ACKs (for > example) Either the "established" or the "tcpflags !syn,ack" keywords in a rule adding matching packets to a high-priority queue ought to do it...? Or perhaps you meant something more specific than just "TCP packets with TH_ACK" set? :-) Anyway, I'm not convinced that trying to classify packets within an established TCP connection in order to place them on different queues is a really good idea, since you're quite likely to reorder the packets by doing so. I'd expect both latency and bandwidth of a TCP connection to suffer very noticably if more than 10% or so of the packets arrive out of order... [ Hmm. I suppose that one could make an exception to the above generalization if URG was set, but the TCP stack already makes an effort to prioritize and deliver out-of-band urgent stuff as quickly as possible, anyway, right? ] -- -Chuck