Date: Wed, 12 Jan 2005 21:51:11 -0800 From: Brooks Davis <brooks@one-eyed-alien.net> To: Julian Elischer <julian@elischer.org> Cc: net@freebsd.org Subject: Re: TCP out-of-order packets. Message-ID: <20050113055111.GA11141@odin.ac.hmc.edu> In-Reply-To: <41E5C9D8.4090209@elischer.org> References: <41E5C9D8.4090209@elischer.org>
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[-- Attachment #1 --] On Wed, Jan 12, 2005 at 05:07:36PM -0800, Julian Elischer wrote: > > I have a link which is provided by someone else that is 7 x E1s aggregated. > At leat it looks that way to me when I get to see it. however I have > 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 > packets. > groups of upto 10 packets may appear in random order. (Maybe more, bu tI > have seen 10) > > in fact packets are rarely IN order. > > This plays havoc with the tcp sessions. > > 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, > so that the receiver would > see a stream of IN-order packets, with occasional delays. > > firstly, does anyone have any tools to do this already (why build when > you can borrow) > and secondly, does anyone have any experience with this sort of problem? > > I have no control over or access to the link.. all I have is a promise > that they will deliver > 14Mb/Sec. with approc 300mSec. RTT to me but there is no promise about > packet order. > > 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 -- 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 [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQFB5gxPXY6L6fI4GtQRAm4uAKCeE/xte3E5E3iceWBBjvzd5lpp3ACgiEo3 mF9X3uBOdAHXYB/Nd/1xkQ0= =P+o4 -----END PGP SIGNATURE-----
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