From owner-freebsd-hackers  Fri Sep 27 09:30:42 1996
Return-Path: owner-hackers
Received: (from root@localhost)
          by freefall.freebsd.org (8.7.5/8.7.3) id JAA29330
          for hackers-outgoing; Fri, 27 Sep 1996 09:30:42 -0700 (PDT)
Received: from rah.star-gate.com (rah.star-gate.com [204.188.121.18])
          by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id JAA29293
          for <freebsd-hackers@FreeBSD.ORG>; Fri, 27 Sep 1996 09:30:38 -0700 (PDT)
Received: from rah.star-gate.com (localhost.star-gate.com [127.0.0.1]) by rah.star-gate.com (8.7.6/8.7.3) with ESMTP id JAA04483; Fri, 27 Sep 1996 09:30:26 -0700 (PDT)
Message-Id: <199609271630.JAA04483@rah.star-gate.com>
X-Mailer: exmh version 1.6.9 8/22/96
To: Rohit Dube <rohit@cs.UMD.EDU>
cc: dg@Root.COM, freebsd-hackers@FreeBSD.ORG
Subject: Re: Giant Sized Ethernet Packets 
In-reply-to: Your message of "Fri, 27 Sep 1996 08:59:16 EDT."
             <199609271259.IAA11945@darling.cs.UMD.EDU> 
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Date: Fri, 27 Sep 1996 09:30:26 -0700
From: Amancio Hasty <hasty@rah.star-gate.com>
Sender: owner-hackers@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk

Before I start hacking... Well, you will be non-conformant and some 
equipment will not work. You have to experiment a little and find
out what works. In our case, we had a business reason for trying
it out . I personally had good success with UTP machine to machine;however,
the project call for thin net.

I am sure that Julian can fill in more about TRW's net configuration .


Given that you need a modest increase on the size of the packets,
all what you need is to enable the BIG PACKET option in the driver
and increase the mtu size. My suggestion is to first try two FreeBSD
boxes directly connected with UTP to verify that indeed that
the big packets works.

	Amancio

>From The Desk Of Rohit Dube :
> On Wed, 18 Sep 1996 20:50:52 -0700 dg@root.com writes:
> =>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. It also appears that it is possible to
> =>generate larger than 1500 byte packets, but the frames wouldn't be ethernet
> =>(the type/length field would not be IEEE 802.3) and you'd have to invent yo
ur
> =>own encapsulation. ...that's how I read it, anyway. Perhaps Matt Thomas wil
l
> =>correct me on this.
> =>
> =>-DG
> =>
> =>David Greenman
> =>Core-team/Principal Architect, The FreeBSD Project
> 
> Another quick question before I start hacking : DO hubs have a problem
> with 1500+ bytes packet. I am using an Asante 100BaseTX hub to hook up
> my FreeBSD machines. If the hub is intelligent and drops packets greater
> than 1500 bytes in size, then I would be in trouble even before I start.
> 
> Julian/Amancio : care to share you configuartion?
> 
> Thanks.
> 
> --rohit.
> 
>