From owner-freebsd-net@FreeBSD.ORG Tue May 8 11:22:17 2007 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id CDE1816A400 for ; Tue, 8 May 2007 11:22:17 +0000 (UTC) (envelope-from peterjeremy@optushome.com.au) Received: from turion.vk2pj.dyndns.org (c220-239-3-125.belrs4.nsw.optusnet.com.au [220.239.3.125]) by mx1.freebsd.org (Postfix) with ESMTP id 52F8013C45B for ; Tue, 8 May 2007 11:22:17 +0000 (UTC) (envelope-from peterjeremy@optushome.com.au) Received: from turion.vk2pj.dyndns.org (localhost.vk2pj.dyndns.org [127.0.0.1]) by turion.vk2pj.dyndns.org (8.14.1/8.14.1) with ESMTP id l48BMF6G001425; Tue, 8 May 2007 21:22:15 +1000 (EST) (envelope-from peter@turion.vk2pj.dyndns.org) Received: (from peter@localhost) by turion.vk2pj.dyndns.org (8.14.1/8.14.1/Submit) id l48BMFGr001424; Tue, 8 May 2007 21:22:15 +1000 (EST) (envelope-from peter) Date: Tue, 8 May 2007 21:22:15 +1000 From: Peter Jeremy To: suvashrestha@wlink.com.np Message-ID: <20070508112215.GF838@turion.vk2pj.dyndns.org> References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Y5rl02BVI9TCfPar" Content-Disposition: inline In-Reply-To: X-PGP-Key: http://members.optusnet.com.au/peterjeremy/pubkey.asc User-Agent: Mutt/1.5.14 (2007-02-12) Cc: freebsd-net@freebsd.org Subject: Re: bridge query 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, 08 May 2007 11:22:17 -0000 --Y5rl02BVI9TCfPar Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2007-May-08 14:20:27 +0500, suvashrestha@wlink.com.np wrote: >i am using freebox 5.4 as a bridge using dummynet. =2E.. >When I add delay of 250ms and plr of 0.05 (5%), the packet transfer falls >to 80Kbit/s. How are you measuring packet transfer (single TCP socket, multiple TCP sockets or UDP) and what were you expecting? For a TCP connection, the window size needs to be able to handle at least 1 RTT (0.5 second in this case) of data. This translates to a total of 5Mb (~640KB) outstanding data to get 10Mbps throughput. With only a single cnnection, you would need a 640KB window size - which is far larger (an order of magnitude or so) than typical. TCP is also designed to work on a mostly lossless link. I am not sure how much a 5% packet loss will affect it but I would expect it to be significant. I'm not sure how to optimise throughput in this situation. --=20 Peter Jeremy --Y5rl02BVI9TCfPar Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (FreeBSD) iD8DBQFGQF1n/opHv/APuIcRAvewAJsHDb324nYSB4HNqgpPJ8t2lk2YRwCglPhf gMDoyTTeHt6/jPeHtDb7CSs= =Zmpu -----END PGP SIGNATURE----- --Y5rl02BVI9TCfPar--