From owner-freebsd-net Tue Aug 3 13:32:25 1999 Delivered-To: freebsd-net@freebsd.org Received: from fever.semiotek.com (H253.C225.tor.velocet.net [209.167.225.253]) by hub.freebsd.org (Postfix) with ESMTP id CB1B014D85 for ; Tue, 3 Aug 1999 13:32:09 -0700 (PDT) (envelope-from jread@fever.semiotek.com) Received: (from jread@localhost) by fever.semiotek.com (8.8.8/8.8.7) id QAA18930 for freebsd-net@freebsd.org; Tue, 3 Aug 1999 16:31:57 -0400 (EDT) (envelope-from jread) Message-ID: <19990803163157.C17569@semiotek.com> Date: Tue, 3 Aug 1999 16:31:57 -0400 From: Justin Wells To: freebsd-net@freebsd.org Subject: how to configure FreeBSD for unreliable network Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.93.1i Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org I have a FreeBSD 3.2 box sitting on a network that has a reasonably fast connection to the outside world. Linux boxes on this network get 30-40k/sec, but my FreeBSD box gets less than 1k/sec on the same link. The link has fairly good bandwidth (2-3 Mbit) but horrible reliability (sometimes up to 20-30% packet loss). Basically it's an ADSL link operating a little too far away from the CO, so the cable length is longer than the spec says it should be--the consequence being a fast, but not very reliable link. Nevertheless, FreeBSD gets 1k/sec whereas Linux gets 30-40k/sec. (Actually, only recent Linux kernels perform well, older ones suffer the same way that FreeBSD does, making me think it's a tcp stack issue.) It seems that what's happening is that there's a long retry in FreeBSD, and a nearly instantaneous one in Linux. So while FreeBSD stops and waits for nearly a full second before retrying, Linux recovers and resumes. This is just my theory and may be full of BS. I don't really totally know what's going on--I do know that I can start a huge number of these 1k/sec transfers without slowing any of them down any further, so the bandwidth is obviously there. At any rate--what can I do to configure my FreeBSD boxes to work well across this lousy link? It's embarassing that Linux is showing better network performance ;-) Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message