Date: Mon, 22 May 2006 10:22:10 -0400 From: Mark Allman <mallman@icir.org> To: Marcin Jessa <lists@yazzy.org>, mag@intron.ac, freebsd-net@freebsd.org Subject: Re: How to Quicken TCP Re-transmission? Message-ID: <20060522142210.2A8FF77AF5C@guns.icir.org>
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--=_bOundary Content-Type: text/plain Content-Disposition: inline > > > You can take a look at SCPS - http://www.scps.org/ Their protocol is > > used on lossy links with big latency and packet loss (such as > > satellites) and overcomes shortcomings of TCP. It works with divert > > mechanism of FreeBSD and I ported the tap device part as well to both > > NetBSD / FreeBSD (experimental). > > It's not clear to me that this is going to help. Fundamentally, TCP and > SCTP share the same congestion control response. At 30% packet loss > SCTP ought to be as unusable as TCP. Both consider losses to be > indications of network congestion. > > SCTP does have some things built-in that need to be added onto TCP > (e.g., SACK). So, we could expect more consistent behavior from SCTP > across implementations and platforms. But, in the end the performance > of both is proportional to 1/sqrt(p) where p is the loss rate. So, as > the loss rate increases performance decreases. At 30% you're > essentially cooked no matter which you use. Ugh... Monday mornings... You'll note that what I quoted was about "SCPS" and what I wrote about was "SCTP". These are different. Ignore me. allman --=_bOundary Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (FreeBSD) iD8DBQFEcckSWyrrWs4yIs4RAnr/AJ0UfzYCV1aI+b8LtqLk+H4G2GvV3gCcDr/r Tp7JKez5J8y8i66/u+beXEA= =USBM -----END PGP SIGNATURE----- --=_bOundary--
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