From owner-freebsd-net@FreeBSD.ORG Fri Oct 17 15:45:55 2003 Return-Path: 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 D5B1E16A4B3 for ; Fri, 17 Oct 2003 15:45:55 -0700 (PDT) Received: from smtp.netli.com (ip2-pal-focal.netli.com [66.243.52.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id D9D8943FE0 for ; Fri, 17 Oct 2003 15:45:54 -0700 (PDT) (envelope-from vlm@netli.com) Received: (qmail 11472 invoked by uid 84); 17 Oct 2003 22:45:54 -0000 Received: from vlm@netli.com by l3-1 with qmail-scanner-0.96 (uvscan: v4.1.40/v4121. . Clean. Processed in 0.163551 secs); 17 Oct 2003 22:45:54 -0000 Received: from unknown (HELO netli.com) (172.17.1.12) by mx01-pal-lan.netli.lan with SMTP; 17 Oct 2003 22:45:54 -0000 Message-ID: <3F907152.3080706@netli.com> Date: Fri, 17 Oct 2003 15:46:42 -0700 From: Lev Walkin Organization: Netli, Inc. User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.4) Gecko/20030820 X-Accept-Language: ru, en-us, en MIME-Version: 1.0 To: Carl Mascott References: <200310171830.h9HIUnSr000572@callisto.local> In-Reply-To: <200310171830.h9HIUnSr000572@callisto.local> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit cc: freebsd-net@freebsd.org Subject: Re: TCP window size issues X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 17 Oct 2003 22:45:56 -0000 Carl Mascott wrote: > I have a few TCP window size issues. [skip] > 3. RFC 793 (TCP) says that shrinking the receive window after > connection is established is "strongly discouraged". I'm > currently shrinking the receive window on my default route > (PPP link) from 32 KB to 4 KB with settings in > /etc/ppp/ppp.conf. (Had to back out patch in PR 11966.) [skip] > How likely am I to get into trouble by shrinking the TCP > receive window? Likely enough that I should make the RFC793 has nothing to do with the defaults you're setting in ppp.conf. RFC merely says that the TCP implementation _itself_ should not shrink window after establishing a TCP connection. If the default dictates 4k, the TCP implementation will use 4k and will not advertise a much smaller window without having accepted that much data. -- Lev Walkin vlm@netli.com