From owner-freebsd-net Wed Jun 19 0:49:59 2002 Delivered-To: freebsd-net@freebsd.org Received: from patrocles.silby.com (d182.as20.nwbl0.wi.voyager.net [169.207.139.184]) by hub.freebsd.org (Postfix) with ESMTP id 4756E37B409 for ; Wed, 19 Jun 2002 00:49:53 -0700 (PDT) Received: from patrocles.silby.com (localhost [127.0.0.1]) by patrocles.silby.com (8.12.4/8.12.4) with ESMTP id g5J7pacv024083; Wed, 19 Jun 2002 02:51:36 -0500 (CDT) (envelope-from silby@silby.com) Received: from localhost (silby@localhost) by patrocles.silby.com (8.12.4/8.12.4/Submit) with ESMTP id g5J7pLK2024080; Wed, 19 Jun 2002 02:51:36 -0500 (CDT) X-Authentication-Warning: patrocles.silby.com: silby owned process doing -bs Date: Wed, 19 Jun 2002 02:51:21 -0500 (CDT) From: Mike Silbersack To: ef90b7323131bdf05e Cc: freebsd-net@freebsd.org Subject: Re: How cwnd is set after a loss in FreeBSD TCP? In-Reply-To: <20020618102912.DAA3237B40D@hub.freebsd.org> Message-ID: <20020619024843.D23787-100000@patrocles.silby.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Tue, 18 Jun 2002, ef90b7323131bdf05e wrote: > My explanation to this is that the ssthresh is not exactly half of the cwnd after > detecting the loss. However, the explanation seems contradicts with RFC2581, which > say ssthresh must be no more than max( FlightSize /2, 2*SMSS). The behavior > puzzled me for a while. Is it a bug or just the right behavior? Can anyone help to > explain it? > > I have dump file the the figure of this behavior, if anyone want, I will email > it. > > ************************************** > Lu Guohan It's certainly possible that there's a bug. To explain the behavior, you'll probably have to wander around tcp_output.c a bit. When doing so, also take into consideration new reno (rfc 2582, I think.) If you find something that you believe is a definite problem, please post back to this list. I'd love to help, but I'm busy with other matters at the moment. Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message