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To: Sten Daniel Soersdal <netslists@gmail.com>
From: Mike Karels <karels@karels.net>
In-reply-to: Your message of Sat, 20 Oct 2007 00:34:58 +0200.
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Date: Fri, 19 Oct 2007 18:55:39 -0500
Sender: karels@karels.net
Cc: Len Gross <sandiegobiker@gmail.com>, freebsd-net@freebsd.org
Subject: Re: Disable Exponential Backoff (retry) on Ethernet? 
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> Len Gross wrote:
> > Thanks so much for the response.  Here is some additional information.
> > 
> > I'm trying to emulate an RF network where there are colisions (e.g. "Aloha"
> > type protocol) so I actually need collisions!  I had forgotten that modern
> > hardware
> > essentially eliminated them.  So, lets say I can find/use an "old hub",
> > can I control the number of retries?  Maybe I have to find some old NICs and
> > old drivers?

> That would be very NIC specific. Retries are done in NIC hardware as far 
> as i know.

The last NICs that I remember with control over retries were some
of the original 3Com NICs.  They supported only 10Base5, the original
thick coax Ethernet (remember vampire taps?).  They plugged into a
Unibus on a VAX, or a PDP-11 I suppose.  I think they were about
$3000 each at the time.

		Mike