From owner-freebsd-stable Mon Jul 3 20:39:23 2000 Delivered-To: freebsd-stable@freebsd.org Received: from cs.waikato.ac.nz (taupo.cs.waikato.ac.nz [130.217.248.134]) by hub.freebsd.org (Postfix) with ESMTP id 4C59837B5E7 for ; Mon, 3 Jul 2000 20:39:20 -0700 (PDT) (envelope-from joerg@cs.waikato.ac.nz) Received: (from joerg@localhost) by cs.waikato.ac.nz (8.9.3/8.9.3) id PAA61875; Tue, 4 Jul 2000 15:39:14 +1200 (NZST) (envelope-from joerg) Date: Tue, 4 Jul 2000 15:39:14 +1200 From: Joerg Micheel To: David Gilbert Cc: freebsd-stable@FreeBSD.ORG Subject: Re: Ethernet MTUs > 1500? Message-ID: <20000704153914.C60136@cs.waikato.ac.nz> References: <14689.22689.894466.908666@trooper.velocet.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <14689.22689.894466.908666@trooper.velocet.net>; from dgilbert@velocet.ca on Mon, Jul 03, 2000 at 11:23:13PM -0400 Organization: Dept of Computer Science, University of Waikato, Hamilton, New Zealand Project: WAND - Waikato Applied Network Dynamics, DAG Operating-System: ... powered by FreeBSD Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Mon, Jul 03, 2000 at 11:23:13PM -0400, David Gilbert wrote: > But a number of devices seem to allow for MTUs > 1500 on 100Mb > ethernet... and several people have told me that the standard allows > for packets bigger than 1500 bytes. The limit is 1536. That is hex 0x600, a value of importance if using 802.x networks. A value below 0x600 indicates the length of an additional header in the EtherType field. If this value is above 0x600 it indicates a certain protocol (such as 0x800 for IP, 0x806 for IP ARP). I would not twiddle with the settings, the extra gain is very low and you'll face all sorts of compatibility issues with devices not supporting it. Joerg -- Joerg B. Micheel Email: Waikato Applied Network Dynamics Phone: +64 7 8384794 The University of Waikato, CompScience Fax: +64 7 8585095 Private Bag 3105 Pager: +64 868 38222 Hamilton, New Zealand Plan: TINE and the DAG's To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message