From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Furniss Subject: Controlling TCP window size Date: Tue, 16 May 2006 12:06:57 +0100 Message-ID: <4469B251.3050901@andyfurniss.entadsl.com> Reply-To: lists@andyfurniss.entadsl.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from s2.ukfsn.org ([217.158.120.143]:2789 "EHLO mail.ukfsn.org") by vger.kernel.org with ESMTP id S1751775AbWEPLFh (ORCPT ); Tue, 16 May 2006 07:05:37 -0400 Received: from [192.168.0.3] (unknown [87.127.23.106]) by mail.ukfsn.org (Postfix) with ESMTP id 19633E7029 for ; Tue, 16 May 2006 11:58:42 +0100 (BST) To: netdev@vger.kernel.org Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org I've been doing some testing of my new wan connection and noticed that when I specify a window with ip route it still changes after a while. Using 2.6.16.11 and latest iproute2. ip ro del default ip ro add default via 192.168.0.1 window 28000 ip ro ls 192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.3 default via 192.168.0.1 dev eth0 window 28000 timestamps and window scaling are off using reno. Downloading a 5 meg file I advertise the correct window - the whole multiple of my mss below 28000 = 27322. After about 1300 lines of the dump the window creeps back up to 32767. 001959 IP 81.31.115.186.80 > 192.168.0.3.42305: . 1051979:1053417(1438) ack 123 win 57520 000011 IP 192.168.0.3.42305 > 81.31.115.186.80: . ack 1053417 win 27322 002030 IP 81.31.115.186.80 > 192.168.0.3.42305: . 1053417:1054855(1438) ack 123 win 57520 001962 IP 81.31.115.186.80 > 192.168.0.3.42305: . 1054855:1056293(1438) ack 123 win 57520 000011 IP 192.168.0.3.42305 > 81.31.115.186.80: . ack 1056293 win 27322 003020 IP 81.31.115.186.80 > 192.168.0.3.42305: . 1056293:1057731(1438) ack 123 win 57520 001968 IP 81.31.115.186.80 > 192.168.0.3.42305: . 1057731:1059169(1438) ack 123 win 57520 000012 IP 192.168.0.3.42305 > 81.31.115.186.80: . ack 1059169 win 30198 002024 IP 81.31.115.186.80 > 192.168.0.3.42305: . 1059169:1060607(1438) ack 123 win 57520 000012 IP 192.168.0.3.42305 > 81.31.115.186.80: . ack 1060607 win 32767 001980 IP 81.31.115.186.80 > 192.168.0.3.42305: . 1060607:1062045(1438) ack 123 win 57520 000011 IP 192.168.0.3.42305 > 81.31.115.186.80: . ack 1062045 win 32767 Andy.