From owner-freebsd-net@FreeBSD.ORG Mon Dec 5 12:45:51 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 5F5F816A41F for ; Mon, 5 Dec 2005 12:45:51 +0000 (GMT) (envelope-from saurin@dcs.gla.ac.uk) Received: from mr1.dcs.gla.ac.uk (mr1.dcs.gla.ac.uk [130.209.249.184]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5031943D58 for ; Mon, 5 Dec 2005 12:45:50 +0000 (GMT) (envelope-from saurin@dcs.gla.ac.uk) Received: from ex1.ad.dcs.gla.ac.uk ([130.209.249.157]:25526) by mr1.dcs.gla.ac.uk with esmtp (Exim 4.42) id 1EjFj2-0005GL-De for freebsd-net@freebsd.org; Mon, 05 Dec 2005 12:45:48 +0000 Received: from [130.209.254.20] ([130.209.254.20]) by ex1.ad.dcs.gla.ac.uk over TLS secured channel with Microsoft SMTPSVC(6.0.3790.1830); Mon, 5 Dec 2005 12:45:48 +0000 Mime-Version: 1.0 (Apple Message framework v746.2) Content-Transfer-Encoding: 7bit Message-Id: <79336124-B4D5-43A3-88D2-9FE0D4A4D120@dcs.gla.ac.uk> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed To: freebsd-net@freebsd.org From: Alvaro Saurin Date: Mon, 5 Dec 2005 12:51:56 +0000 X-Mailer: Apple Mail (2.746.2) X-OriginalArrivalTime: 05 Dec 2005 12:45:48.0331 (UTC) FILETIME=[D118E7B0:01C5F999] Subject: Dummynet and fragments 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: Mon, 05 Dec 2005 12:45:51 -0000 Hi, I was wondering if someone could help me with a small problem with dummynet. I have a typical dumbbell configuration where I have a FreeBSD 6.0 machine with dummynet. It is something like this: *----- ubuntu6 | 10.10.3.6 10.10.1.3 10.10.1.4 | ubuntu2 ---[hub]--- ubuntu3------- BSD4------[hub]--- ubuntu5 10.10.2.2 | 10.10.2.3 10.10.3.4 10.10.3.5 | ubuntu1 -----* 10.10.2.1 I want to set the delay, bandwidth, etc. limit in BSD4, using something like > sudo ipfw add 3 pipe 3 all from ubuntu2 to ubuntu6 > sudo ipfw add 4 pipe 4 all from ubuntu6 to ubuntu2 > sudo ipfw pipe 3 config bw 12000Kbit/s queue 17500bytes delay 5ms > sudo ipfw pipe 4 config bw 12000Kbit/s queue 17500bytes delay 5ms for a limit between 'ubuntu2' and 'ubuntu6', leading to a new rule set like > sudo ipfw -a list 00003 0 0 pipe 3 ip from 10.10.2.2 to 10.10.3.6 00004 0 0 pipe 4 ip from 10.10.3.6 to 10.10.2.2 00100 1862 144376 allow ip from any to any via lo0 00200 0 0 deny ip from any to 127.0.0.0/8 00300 0 0 deny ip from 127.0.0.0/8 to any 65000 118952 53165334 allow ip from any to any 65100 0 0 deny log logamount 5000 ip from any to any frag 65535 8 512 deny ip from any to any > sudo ipfw pipe show 00003: 12.000 Mbit/s 5 ms 17 KB 0 queues (1 buckets) droptail 00004: 12.000 Mbit/s 5 ms 17 KB 0 queues (1 buckets) droptail The problem comes here: if I 'ping' between these two machines, everything is fine, but if I 'ping' with a packet size of, ie, 2000, no packets arrive at the receiver. Does it have to do with fragmented packets? Do I have to include any other rule for dealing with fragments? And another question: why do I need to specify a 5ms delay for a total RTT of 40ms? Thanks in advance Alvaro -- Alvaro Saurin