From owner-freebsd-hackers Thu Sep 19 12:31:11 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id MAA05052 for hackers-outgoing; Thu, 19 Sep 1996 12:31:11 -0700 (PDT) Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.211]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id MAA05014 for ; Thu, 19 Sep 1996 12:31:07 -0700 (PDT) Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id MAA01280; Thu, 19 Sep 1996 12:29:44 -0700 From: Terry Lambert Message-Id: <199609191929.MAA01280@phaeton.artisoft.com> Subject: Re: Giant Sized Ethernet Packets To: dg@Root.COM Date: Thu, 19 Sep 1996 12:29:44 -0700 (MST) Cc: rohit@cs.UMD.EDU, freebsd-hackers@freebsd.org In-Reply-To: <199609190350.UAA01225@root.com> from "David Greenman" at Sep 18, 96 08:50:52 pm X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > >I was wondering if it is possible to send giant sized ethernet packets (>1500 > >bytes say 1550) using the current 'de' driver for the SMC 10/100 DEC 21140 > >cards. > > No. > > 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). 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). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.