Subject: Re: very strange ethernet problem
To: Mark Abene <email@example.com>
From: Manuel Bouyer <firstname.lastname@example.org>
Date: 10/31/2000 21:52:00
On Tue, Oct 31, 2000 at 05:12:20AM -0500, Mark Abene wrote:
> I have two hubs in two different rooms. The "A" hub has a half-dozen different
> machines, including the sun3. I just did a test, and enabled SQE on the sun3's
> transceiver. Hub "B" is disconnected from hub "A". The throughput of file
> transfers between the sun3 and other machines on the same hub has dramatically
> increased. But between any other two machines on the same hub, it's horrible.
> Tons of collisions. If I disconnect the sun3 from hub "A", everything is
> normal again.
> Now, I connect hub "B" to hub "A", without the sun3. Hub "B" has the sun4, and
> a freebsd/intel machine. While hub "B" is connected to hub "A", there are
> tons of collisions. Whether between machines on hub "A", or machines on hub
> "B" to "A". Reconnecting the sun3 to hub "A" just makes things worse.
> If I disconnect the sun3, and hub "B" from hub "A", all the machines on hub "A"
> are happy. Throughput is wonderful. Introducing either the sun3 OR hub "B"
> into hub "A" trashes the throughput on hub "A". I've tested this extensively.
> Even if the sun4 isn't connected to hub "B", connecting "B" to "A" trashes
> "A". Doesn't make much sense, does it...
This remember me a stupid thing I did some time ago: by mistake I connected
something to both "uplink" and port 1 of a hub. But on this one "uplink" and
port 1 are the same thing, "uplink" is just a crossed plug.
This generated tons of errors and collistions on this hub.
Could it be something like this ?
Manuel Bouyer, LIP6, Universite Paris VI. Manuel.Bouyer@lip6.fr