Date: Mon, 17 Dec 2001 03:20:51 -0500 (EST) From: Mike Silbersack <silby@silby.com> To: Thomas Zenker <thz@Lennartz-electronic.de> Cc: <stable@freebsd.org>, <net@freebsd.org> Subject: Re: USB ethernet problem Message-ID: <Pine.BSF.4.30.0112170314380.14582-100000@niwun.pair.com> In-Reply-To: <20011217090920.A763@mezcal.tue.le>
next in thread | previous in thread | raw e-mail | index | archive | help
(Moving over to -net, please remove -stable from any cc's) On Mon, 17 Dec 2001, Thomas Zenker wrote: > I allways wondered, why the initial slowstart window is set to one > (well some years I didn't look into the tcp code though). 9 years > ago I had to develope the firmware for a store&foreward radio > network, where I applied a lot of the ideas from the then net/2 tcp > stack. The rtt in such a network is really horrible and packetsizes > have to be taken in account. Anyway the optimal initial window there > was 2. With a window of two there much more probability to get a > connection going, because you send two packets in the beginning, > if the first is lost, the receiption of the second one gets the > first one resent long before the timeout. Otherway round, if the > second is lost... the third is on its way already. With a intital > window of 1 the only recovery is by timeout. The argument against > bigger than two was (at least in my case) not to defeat the intention > of the slowstart. Anyway, in tcp probably something between 2 and > 4 could be considered. > > Thomas RFC 2581 suggests that 4 is a good value (well, not exactly 4, they have a formula which comes out to about 4 in most cases.) I'm inclined to agree that something between 2-4 would be a good value for our non-local slowstart flightsize as well. Maybe after 4.5 is released we can go look into it. (It's too late to be changing stuff now.) Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.BSF.4.30.0112170314380.14582-100000>