From owner-freebsd-net Wed Jan 24 18:35:40 2001 Delivered-To: freebsd-net@freebsd.org Received: from ma4.justnet.ne.jp (ma4p.justnet.ne.jp [133.130.3.12]) by hub.freebsd.org (Postfix) with SMTP id BF6F737B699 for ; Wed, 24 Jan 2001 18:35:19 -0800 (PST) Received: (qmail 11525 invoked from network); Thu, 25 Jan 2001 11:35:15 +0900 Received: (ofmipd 133.1.17.145); Thu, 25 Jan 2001 11:35:15 +0900 Date: Thu, 25 Jan 2001 11:36:42 +0900 Message-Id: <3A6F913A320.7B49GENUINE@ma4.justnet.ne.jp> From: Tatsuhiko Terai To: Garrett Wollman Cc: freebsd-net@freebsd.org Subject: Re: estimation of RTT,RTO from tcpcb parameter In-Reply-To: <200101250133.UAA73836@khavrinen.lcs.mit.edu> References: <3A6F72E71D6.7B48GENUINE@ma4.justnet.ne.jp> <200101250133.UAA73836@khavrinen.lcs.mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver 1.26.02 Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Thank you very much for your kindly advise. >The system timer ticks at a rate of 100 Hz on all IA32 processors. (I >believe on Alphas it ticks at 1024 Hz but I may be imagining it.) >Thus, the period is either 10 ms or 0.98 ms. > >In historic versions of FreeBSD, most TCP timers ticked at 2 Hz while >the others ticked at 5 Hz. This was changed in advance of FreeBSD >4.0. I see. Anyway, it seems to be difficult that estimating RTT, RTO within a LAN envirounment (such as Gigabit connection). Of course, this time scale may be valid for general internet envirounment. I'll study more. Thanks - To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message