From owner-freebsd-net@FreeBSD.ORG Tue May 23 15:17:39 2006 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id AC9EB16A9A5 for ; Tue, 23 May 2006 15:17:39 +0000 (UTC) (envelope-from bv@bilver.wjv.com) Received: from wjv.com (fl-65-40-24-38.sta.sprint-hsd.net [65.40.24.38]) by mx1.FreeBSD.org (Postfix) with ESMTP id DE39843D5D for ; Tue, 23 May 2006 15:17:32 +0000 (GMT) (envelope-from bv@bilver.wjv.com) Received: from bilver.wjv.com (localhost.wjv.com [127.0.0.1]) by wjv.com (8.13.6/8.13.1) with ESMTP id k4NFHTqZ027585; Tue, 23 May 2006 11:17:29 -0400 (EDT) (envelope-from bv@bilver.wjv.com) Received: (from bv@localhost) by bilver.wjv.com (8.13.6/8.13.1/Submit) id k4NFHMRP027584; Tue, 23 May 2006 11:17:22 -0400 (EDT) (envelope-from bv) Date: Tue, 23 May 2006 11:17:22 -0400 From: Bill Vermillion To: Brian Candler Message-ID: <20060523151722.GF26739@wjv.com> References: <20060522115722.15918F1590@smtp.263.net> <20060522130648.GB33204@uk.tiscali.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060522130648.GB33204@uk.tiscali.com> Organization: W.J.Vermillion / Orlando - Winter Park ReplyTo: bv@wjv.com User-Agent: Mutt/1.5.11 X-Spam-Status: No, score=-4.4 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.1.1 X-Spam-Checker-Version: SpamAssassin 3.1.1 (2006-03-10) on bilver.wjv.com Cc: freebsd-net@freebsd.org, mag@intron.ac Subject: Re: How to Quicken TCP Re-transmission? X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: bv@wjv.com List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 23 May 2006 15:17:44 -0000 "Bits dont fail me now!" was what Brian Candler muttered as he hastily typed this on Mon, May 22, 2006 at 14:06 : > On Mon, May 22, 2006 at 07:51:33PM +0800, mag@intron.ac wrote: > > I want to transmit data between host A and host B. The link between > > these two hosts is really bad: PING reports 30% packet loss > How big are the pings? Try > ping -c100 -s1472 x.x.x.x > > to send 1500-byte pings (20 bytes IP header + 8 bytes ICMP > header + 1472 bytes padding). This will give you a more > realistic indication of packet loss for TCP transfers than the > small pings you get by default. The original poster noted that he had used -s1472 in his tests. I had the same exact problem one time as the OP did. Regular pings would go through, data throughput was terrrible and going with every larger packet sizes I found things really fell apart about 500 byte sizes. In my case it was a bad card in a Cisco 12000 switch at the local Level 3 facility where my servers were. There were only about 6 other clients on that card, and since I made the call about 6AM I was the first to notify them. IOW - while your problem may indeed be somewhere in the link don't discount the fact that the problem could be much closer. Have you tried a traceroute to see if it is at one particular link. If your provider does not block it you might try the -R option to ping the site to help pinpoint the source of the problem. Bill -- Bill Vermillion - bv @ wjv . com