Date: Mon, 22 May 2006 10:13:12 -0400 From: Mark Allman <mallman@icir.org> To: Marcin Jessa <lists@yazzy.org> Cc: freebsd-net@freebsd.org, mag@intron.ac Subject: Re: How to Quicken TCP Re-transmission? Message-ID: <20060522141312.5E1D477AF5C@guns.icir.org> In-Reply-To: <20060522153932.1c789788@marcin>
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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. allman --=_bOundary Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (FreeBSD) iD8DBQFEccb4WyrrWs4yIs4RAtCyAKCEVBItiSlfoilRuTjJcF/onorQ+wCeJVng SvLrSgZHNA7rWxeRg9R/g64= =lh/s -----END PGP SIGNATURE----- --=_bOundary--
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