From owner-freebsd-current@FreeBSD.ORG Fri Jan 12 08:02:56 2007 Return-Path: X-Original-To: freebsd-current@FreeBSD.ORG Delivered-To: freebsd-current@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 724B516A503 for ; Fri, 12 Jan 2007 08:02:56 +0000 (UTC) (envelope-from olli@lurza.secnetix.de) Received: from lurza.secnetix.de (lurza.secnetix.de [83.120.8.8]) by mx1.freebsd.org (Postfix) with ESMTP id F36E313C44B for ; Fri, 12 Jan 2007 08:02:55 +0000 (UTC) (envelope-from olli@lurza.secnetix.de) Received: from lurza.secnetix.de (wfwnet@localhost [127.0.0.1]) by lurza.secnetix.de (8.13.4/8.13.4) with ESMTP id l0C82mLd065949; Fri, 12 Jan 2007 09:02:54 +0100 (CET) (envelope-from oliver.fromme@secnetix.de) Received: (from olli@localhost) by lurza.secnetix.de (8.13.4/8.13.1/Submit) id l0C82m8c065948; Fri, 12 Jan 2007 09:02:48 +0100 (CET) (envelope-from olli) Date: Fri, 12 Jan 2007 09:02:48 +0100 (CET) Message-Id: <200701120802.l0C82m8c065948@lurza.secnetix.de> From: Oliver Fromme To: freebsd-current@FreeBSD.ORG, cswiger@mac.com In-Reply-To: <7931EAA6-ED4A-485B-8C3C-FA91E5AD0AAC@mac.com> X-Newsgroups: list.freebsd-current User-Agent: tin/1.8.2-20060425 ("Shillay") (UNIX) (FreeBSD/4.11-STABLE (i386)) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.1.2 (lurza.secnetix.de [127.0.0.1]); Fri, 12 Jan 2007 09:02:54 +0100 (CET) Cc: Subject: Re: squid-2.6.6 + TSO + windows 98 clients X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: freebsd-current@FreeBSD.ORG, cswiger@mac.com List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Jan 2007 08:02:56 -0000 Chuck Swiger wrote: > Denis Shaposhnikov wrote: > > tcpdump of one of failed requests: > > > > 10:35:03.592164 IP 192.168.0.100.1035 > 192.168.0.2.3128: S > > 1423332:1423332(0) win 8192 > > 10:35:03.592274 IP 192.168.0.2.3128 > 192.168.0.100.1035: S > > 2428819522:2428819522(0) ack 1423333 win 0 > > It's interesting that it responds with a zero window size. That is > typically used by the network stack to indicate extreme congestion > and to have the other side wait for some seconds without sending any > more data. > > BTW, why are you using such a small MTU? 576 is Windows' default MTU/MRU for slow PPP (over serial) connections. I think it used to be even less for very slow links (296 bytes, IIRC). The purpose is to reduce the amount of data lost when a spike in the telephone line destroys a packet. That's especially important when using analogue equipment (modems) and old telephone lines. For example, if you have a bad telephone line with an average of one spike (or other kind of glitch) every 2 seconds, that amounts to 16% packet loss on a 38.4k connection with 1500 bytes MTU. With 576 bytes that's only 6% packet loss, and with 296 bytes it's only 3%. Best regards Oliver -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing Dienstleistungen mit Schwerpunkt FreeBSD: http://www.secnetix.de/bsd Any opinions expressed in this message may be personal to the author and may not necessarily reflect the opinions of secnetix in any way. "Being really good at C++ is like being really good at using rocks to sharpen sticks." -- Thant Tessman