From owner-freebsd-stable Mon Jul 3 20:44:24 2000 Delivered-To: freebsd-stable@freebsd.org Received: from sabre.velocet.net (sabre.velocet.net [198.96.118.66]) by hub.freebsd.org (Postfix) with ESMTP id 7693537BAD0 for ; Mon, 3 Jul 2000 20:44:19 -0700 (PDT) (envelope-from dgilbert@office.tor.velocet.net) Received: from office.tor.velocet.net (trooper.velocet.net [216.126.82.226]) by sabre.velocet.net (Postfix) with ESMTP id 65D89137FBC; Mon, 3 Jul 2000 23:43:27 -0400 (EDT) Received: (from dgilbert@localhost) by office.tor.velocet.net (8.9.3/8.9.3) id XAA38684; Mon, 3 Jul 2000 23:43:27 -0400 (EDT) (envelope-from dgilbert) From: David Gilbert MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <14689.23903.87264.511506@trooper.velocet.net> Date: Mon, 3 Jul 2000 23:43:27 -0400 (EDT) To: Joerg Micheel Cc: David Gilbert , freebsd-stable@FreeBSD.ORG Subject: Re: Ethernet MTUs > 1500? In-Reply-To: <20000704153914.C60136@cs.waikato.ac.nz> References: <14689.22689.894466.908666@trooper.velocet.net> <20000704153914.C60136@cs.waikato.ac.nz> X-Mailer: VM 6.75 under 20.4 "Emerald" XEmacs Lucid Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >>>>> "Joerg" == Joerg Micheel writes: Joerg> 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. Joerg> The limit is 1536. That is hex 0x600, a value of importance if Joerg> using 802.x networks. A value below 0x600 indicates the length Joerg> of an additional header in the EtherType field. If this value Joerg> is above 0x600 it indicates a certain protocol (such as 0x800 Joerg> for IP, 0x806 for IP ARP). Joerg> I would not twiddle with the settings, the extra gain is very Joerg> low and you'll face all sorts of compatibility issues with Joerg> devices not supporting it. Well... all I'm looking for is the ability to set 1504 on the etnernet device so that 1500 byte packets will pass on the VLANs. But at least the "dc" driver ignores MTUs larger than 1500. Dave. -- ============================================================================ |David Gilbert, Velocet Communications. | Two things can only be | |Mail: dgilbert@velocet.net | equal if and only if they | |http://www.velocet.net/~dgilbert | are precisely opposite. | =========================================================GLO================ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message