From owner-freebsd-hackers Thu Sep 19 13:49:40 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id NAA11297 for hackers-outgoing; Thu, 19 Sep 1996 13:49:40 -0700 (PDT) Received: from mail12.digital.com (mail12.digital.com [192.208.46.20]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id NAA11248 for ; Thu, 19 Sep 1996 13:49:33 -0700 (PDT) Received: from muggsy.lkg.dec.com by mail12.digital.com (8.7.5/UNX 1.2/1.0/WV) id QAA18708; Thu, 19 Sep 1996 16:35:31 -0400 (EDT) Received: from whydos.lkg.dec.com by muggsy.lkg.dec.com (5.65/DEC-Ultrix/4.3) with SMTP id AA27107; Thu, 19 Sep 1996 16:35:29 -0400 Received: from localhost.lkg.dec.com (localhost.lkg.dec.com [127.0.0.1]) by whydos.lkg.dec.com (8.6.12/8.6.12) with SMTP id QAA26304; Thu, 19 Sep 1996 16:38:09 GMT Message-Id: <199609191638.QAA26304@whydos.lkg.dec.com> X-Authentication-Warning: whydos.lkg.dec.com: Host localhost.lkg.dec.com didn't use HELO protocol X-Mailer: exmh version 1.6.5 12/11/95 To: Terry Lambert Cc: freebsd-hackers@freebsd.org Subject: Re: Giant Sized Ethernet Packets In-Reply-To: Your message of "Thu, 19 Sep 1996 12:29:44 MST." <199609191929.MAA01280@phaeton.artisoft.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 19 Sep 1996 16:38:09 +0000 From: Matt Thomas Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk In <199609191929.MAA01280@phaeton.artisoft.com>, Terry Lambert wrote: > > The answer to this is complicated, but it basically ends up being "no". > > I just spent about 15 minutes looking over the DC21140 hardware reference > > manual. It appears that the chip can except larger frames, but it signals > > an error condition when this occurs, so I don't think you could do this > > as a normal mode of operation. > > I would find this suprising, since it would imply that DEC's cards can't > run DECNet (which has a nasty habit of shoving huge frames around). That is *complete* and *utter* bullsh*t. DECnet uses standard size Ethernet frames. Always has, always will. > I believe huge frames are technically illegal (according to Xerox), > so you should epect that there are hardware limitations which will > be biting you somewhere. This doesn't stop DEC from using them, though, > so I suspect any card capable of DECNet/LAT/MOP/etc. *should* be > physically capable of supporting it. AMD LANCE-based cards should > have no problem (except, as you note, potentially in the driver). Again, no DEC developed protocol uses over-sized Ethernet frames. Why do I know this? Because for the last several years I (as a Digital employee) have owned (and continure to own) all the DECnet specifications. In fact, I implemented most of them as well. -- Matt Thomas Internet: matt@3am-software.com 3am Software Foundry WWW URL: http://www.3am-software.com/bio/matt.html Westford, MA Disclaimer: I disavow all knowledge of this message