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From: "Chris Csanady" <ccsanady@scl.ameslab.gov>
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Date: Wed, 18 Jun 1997 15:34:49 -0500
In-Reply-To: sthaug@nethelp.no
        "Re: Network concurrency problems!?" (Jun 18, 10:18pm)
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To: sthaug@nethelp.no
Subject: Re: Network concurrency problems!?
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On Jun 18, 10:18pm, sthaug@nethelp.no wrote:
> Subject: Re: Network concurrency problems!?
> > Some background..  I have 2 ppro200 machines running 2.2.2 with 4 back
> > to back full duplex 100Mbps connections.  (and 2 10Mbps connections to
> > a real network.)  These are all SMC 10/100 cards, using Matt's 960603
> > drivers.  I am concurrently running NetPIPE over each of the links.  It
> > tests TCP, using a range of increasing block sizes.  (info at
> > http://www.scl.ameslab.gov/netpipe)
> >
> > I don't know if this is a generic problem or driver specific, but when I
> > have 2-4 cards in a machine, I am only able to saturate one link with
> > larger transfer sizes. With 4 cards, at approx 6k, and 16k, two of the
> > pipes are completely starved.  The last runs about 10Mbps slower.  Also,
> > there appear to be hundreds of thousands of collisions on a couple of the
> > interfaces.  (This should be impossible, correct?)
>
> Collisions are a sign that your interfaces are *not* running full duplex.

The cards say they are full duplex.  The little light is on..  A switch also
tells me the same if I plug them in.

> Also, if you expect a PPro-200 to saturate 4 100 Mbps links, I think you
> are a wee bit optimistic. (One link, no problem.)

I don't expect it to.  Although..  I am concerned that when one is saturated,
no packets go through the others.  This is a Bad Thing(tm)..

Chris