From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759418AbXGDJL1 (ORCPT ); Wed, 4 Jul 2007 05:11:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756326AbXGDJLU (ORCPT ); Wed, 4 Jul 2007 05:11:20 -0400 Received: from ihemail1.lucent.com ([135.245.0.33]:56208 "EHLO ihemail1.lucent.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755215AbXGDJLT (ORCPT ); Wed, 4 Jul 2007 05:11:19 -0400 Message-ID: <468B642D.9030109@alcatel-lucent.com> Date: Wed, 04 Jul 2007 17:11:09 +0800 From: gshan User-Agent: Thunderbird 1.5.0.10 (X11/20070221) MIME-Version: 1.0 To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Big sized packets have been dropped strangly Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 04 Jul 2007 09:11:14.0456 (UTC) FILETIME=[459B7980:01C7BE1B] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hey Guys, I got a strange problem recently but no ideas, so to post the question here. We have a FPGA what finish ATM AAL5 to ethernet frame, and CPU receives IP packets from it. The interface based on the FPGA (called sar0) has been bound with several IP addresses. When the MTU of the interface is configurated to 1500, trivial packets can be received, but big-sized packets are dropped. If the MTU is increased to 9500, everything is ok except the NFS connection. We mounted with another machine through sar0. When the MTU is 9500, the speed of the NFS becomes very very slow (it almost took 10 minutes to transfer 100KB files). I don't know why it is and how to solve it. Any suggestions are appreciated! Thanks, Gavin