From owner-freebsd-hackers Thu Nov 29 19:28:21 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from ussenterprise.ufp.org (ussenterprise.ufp.org [208.185.30.210]) by hub.freebsd.org (Postfix) with ESMTP id 57B2037B405 for ; Thu, 29 Nov 2001 19:28:15 -0800 (PST) Received: (from bicknell@localhost) by ussenterprise.ufp.org (8.11.1/8.11.1) id fAU3S9X67485; Thu, 29 Nov 2001 22:28:09 -0500 (EST) (envelope-from bicknell) Date: Thu, 29 Nov 2001 22:28:09 -0500 From: Leo Bicknell To: Pierre Beyssac Cc: Josh Paetzel , jc@irbs.com, freebsd-hackers@FreeBSD.ORG Subject: Re: FreeBSD performing worse than Linux? Message-ID: <20011129222809.A67159@ussenterprise.ufp.org> Mail-Followup-To: Pierre Beyssac , Josh Paetzel , jc@irbs.com, freebsd-hackers@FreeBSD.ORG References: <20011128153817.T61580@monorchid.lemis.com> <15364.38174.938500.946169@caddis.yogotech.com> <20011129004234.A16101@exuma.irbs.com> <20011130010354.A21307@fasterix.frmug.org> <20011129184414.F522@twincat.vladsempire.net> <20011130022547.A21889@fasterix.frmug.org> <20011129204225.A63957@ussenterprise.ufp.org> <20011130032345.A23415@fasterix.frmug.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20011130032345.A23415@fasterix.frmug.org>; from pb@fasterix.freenix.org on Fri, Nov 30, 2001 at 03:23:45AM +0100 Organization: United Federation of Planets Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Fri, Nov 30, 2001 at 03:23:45AM +0100, Pierre Beyssac wrote: > I can't reproduce this result, 16K fills a T1 for 11 ms, which is > 22000 km (at 2/3 of light speed), enough to get halfway round the > earth... Your math is a little funny. 4000 km New York to LA c = 300,000 km/sec Speed of light in fiber, approximately .66 c, or 198,000 km/sec. Approximate sum of buffering + serialization delay in the network, is a 15% penalty, or 168,300 kph. total speed. 4000 km one way == 8000 km two way, 8000 / 168300 = 47ms in my book, theoretial optimum. With an RTT of 47ms, you can move 16k per RTT, or or about 340k/sec. * If you find a cross country RTT of 47 ms I'll personally send you $20. around 60-65 is normal for "good circuits", and 70-90 is not wholely unusual. * The 340k/sec assumes perfect network conditions, that is no dropped or delayed packets. Please search the archives. There are reams of information about this. -- Leo Bicknell - bicknell@ufp.org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/ Read TMBG List - tmbg-list-request@tmbg.org, www.tmbg.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message