Date: Sat, 10 Aug 2002 21:58:27 -0500 (CDT) From: Mike Silbersack <silby@silby.com> To: Oleg Polyakov <opolyakov@yahoo.com> Cc: freebsd-net@freebsd.org Subject: Re: Initial congestion window increase Message-ID: <20020810215044.O62906-100000@patrocles.silby.com> In-Reply-To: <20020809201429.56558.qmail@web10407.mail.yahoo.com>
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On Fri, 9 Aug 2002, Oleg Polyakov wrote: > Here is a patch allowing to increase TCP's initial congestion > window up to 4 mss but less then 4380 bytes as specified in > experimental RFC 2414 and draft-ietf-tsvwg-initwin-04.txt. > It doesn't touch idle congestion window as per draft. Despite this change being in an RFC, I'm not sure that it's really worth implementing. While increasing the slowstart flightsize might do wonders for benchmarks of short connections, the actual effect on real world tests seems much more murky. I believe that there _is_ an argument for using mss * 2 as the default flightsize, however. Supposedly, some OSes using delayed ACKs will delay the first ack, causing a 200ms delay which can really slow down the transfer of small web pages / etc. If you can find (tcpdump) evidence to back this up, I could agree with raising the value to 2 * mss. Beyond that, however, seems like a cheap way to inflate benchmarks and cause congestion. Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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