From owner-freebsd-net@FreeBSD.ORG Thu Jan 13 05:48:16 2005 Return-Path: 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 2933F16A4CE for ; Thu, 13 Jan 2005 05:48:16 +0000 (GMT) Received: from odin.ac.hmc.edu (Odin.AC.HMC.Edu [134.173.32.75]) by mx1.FreeBSD.org (Postfix) with ESMTP id F0F3643D31 for ; Thu, 13 Jan 2005 05:48:15 +0000 (GMT) (envelope-from brdavis@odin.ac.hmc.edu) Received: from odin.ac.hmc.edu (localhost.localdomain [127.0.0.1]) by odin.ac.hmc.edu (8.13.0/8.13.0) with ESMTP id j0D5pBnu028459; Wed, 12 Jan 2005 21:51:11 -0800 Received: (from brdavis@localhost) by odin.ac.hmc.edu (8.13.0/8.13.0/Submit) id j0D5pBf0028458; Wed, 12 Jan 2005 21:51:11 -0800 Date: Wed, 12 Jan 2005 21:51:11 -0800 From: Brooks Davis To: Julian Elischer Message-ID: <20050113055111.GA11141@odin.ac.hmc.edu> References: <41E5C9D8.4090209@elischer.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="AhhlLboLdkugWU4S" Content-Disposition: inline In-Reply-To: <41E5C9D8.4090209@elischer.org> User-Agent: Mutt/1.4.1i X-Virus-Scanned: by amavisd-new X-Spam-Status: No, hits=0.0 required=8.0 tests=none autolearn=no version=2.63 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on odin.ac.hmc.edu cc: net@freebsd.org Subject: Re: TCP out-of-order packets. X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 13 Jan 2005 05:48:16 -0000 --AhhlLboLdkugWU4S Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jan 12, 2005 at 05:07:36PM -0800, Julian Elischer wrote: >=20 > I have a link which is provided by someone else that is 7 x E1s aggregate= d. > At leat it looks that way to me when I get to see it. however I have=20 > only been able to get > 60kB.sec across this, despite having a tcp window size of 131072 bytes.. > After investigation it appears that the link is massively re-orderring=20 > packets. > groups of upto 10 packets may appear in random order. (Maybe more, bu tI= =20 > have seen 10) >=20 > in fact packets are rarely IN order. >=20 > This plays havoc with the tcp sessions. >=20 > I was thinking of writing a hacked up version of NATD that > instead of doing NAT, just did a pre-sort on packets from each session,= =20 > so that the receiver would > see a stream of IN-order packets, with occasional delays. >=20 > firstly, does anyone have any tools to do this already (why build when=20 > you can borrow) > and secondly, does anyone have any experience with this sort of problem? >=20 > I have no control over or access to the link.. all I have is a promise=20 > that they will deliver > 14Mb/Sec. with approc 300mSec. RTT to me but there is no promise about=20 > packet order. >=20 > I just get a 100Mb ethernet cable. Have you tried Andre's TCP reassembly rewrite? He says he saw significant improvements in the face of major reordering. http://www.mail-archive.com/freebsd-net@freebsd.org/msg14064.html -- Brooks --=20 Any statement of the form "X is the one, true Y" is FALSE. PGP fingerprint 655D 519C 26A7 82E7 2529 9BF0 5D8E 8BE9 F238 1AD4 --AhhlLboLdkugWU4S Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQFB5gxPXY6L6fI4GtQRAm4uAKCeE/xte3E5E3iceWBBjvzd5lpp3ACgiEo3 mF9X3uBOdAHXYB/Nd/1xkQ0= =P+o4 -----END PGP SIGNATURE----- --AhhlLboLdkugWU4S--