From owner-freebsd-mobile  Wed Jun 19  9:41:45 2002
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To: freebsd-mobile@freebsd.org
Subject: Re: wireless lans with multiple accesspoints 
In-reply-to: Your message of "Wed, 19 Jun 2002 11:18:43 EDT."
             <20020619151842.GD23903@pir.net> 
Date: Wed, 19 Jun 2002 09:41:41 -0700
From: "Kevin Oberman" <oberman@es.net>
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> Date: Wed, 19 Jun 2002 11:18:43 -0400
> From: Peter Radcliffe <pir@pir.net>
> Sender: owner-freebsd-mobile@FreeBSD.ORG
> 
> Kevin Oberman <oberman@es.net> probably said:
> > Simply stated, no. Per 802.3, collisions are a local event. There is
> > no way for a switch to "send a collision" and the section of 802.3 on
> > full-duplex is specific that collision detection MUST be disabled. A
> > switch does not divide a broadcast domain, but does divide a collision
> > domain.
> 
> In theory, theory and practice are the same. In practice, they are not.
> 
> Collision detection is not always disabled, collisions do happen if
> they are supposed to or not.

This is simply not true. If any equipment running full-duplex EVER
reports a collision it is BADLY broken. This is cast in stone and
central to the full-duplex spec. I have LOTS of switches and hundreds
of nodes and have never seen a collision on an interface that was
running full-duplex.

R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman@es.net			Phone: +1 510 486-8634

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