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Date:      Wed, 07 Oct 1998 17:15:50 -0700
From:      Mike Smith <mike@smith.net.au>
To:        Archie Cobbs <archie@whistle.com>
Cc:        hackers@FreeBSD.ORG
Subject:   Re: How to send data between two network cards directly? 
Message-ID:  <199810080015.RAA03646@dingo.cdrom.com>
In-Reply-To: Your message of "Wed, 07 Oct 1998 17:01:28 PDT." <199810080001.RAA23283@bubba.whistle.com> 

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> Mike Smith writes:
> > > > > I have two machines connected with two network cards directly
> > > > > together via 10Base2. I would like to send data from one
> > > > > machine two the other without doing IP or any other
> > > > > protocol.
> > > > 
> > > > You have to have some protocol, or you can't tell what any given item 
> > > > of data is.
> > > 
> > > OK, maybe I desribed it in a wrong way. I would like to use
> > > the most basic protocol that is available. No overhead,
> > > no error correction, no nothing...
> > 
> > You can't do this.  Ethernet implicitly involves several protocols, 
> > each with their own overheads and error correction.
> 
> Not true.. Ethernet is just synchronous HDLC with a 32 bit checksum.
> You can send and receive raw Ethernet frames using bpf(4).

I see at least two there; the Ethernet protocol (implemented 
substantially in hardware) and the interface to the Ethernet card.

Anyway, my response was to the "no overhead, no error correction, no 
nothing".  Ethernet has mandatory overhead, mandatory (usually hardware) 
error detection, and no "no nothing". 

I think I was right. 8)
-- 
\\  Sometimes you're ahead,       \\  Mike Smith
\\  sometimes you're behind.      \\  mike@smith.net.au
\\  The race is long, and in the  \\  msmith@freebsd.org
\\  end it's only with yourself.  \\  msmith@cdrom.com



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