Donald,
I didnt know that it wasnt a problem to observe collisions. It
surprised me to see collisions on what is effectively a point-to-point
link. The only two devices on that wire are the card and the cablemodem -
so when I saw collisions, I thought maybe there was some mismatch. Thanks
for the clarification.
I did not understand your statement about a duplex mismatch. Are
you saying that the autonegotiation would have ensured a full duplex
connection and that forcing the card to full_duplex will cause a
problem? Or are you saying that the card may be operating at half-duplex,
but since that is what was negotiated, that is the best setting? I am
unable to tell whether the card is operating at full or half duplex - is
there a way I can find this out?
Thanks,
Kenneth
On Thu, 26 Jul 2001, Donald Becker wrote:
> On Thu, 26 Jul 2001, Kenneth Stephen wrote:
>
> > I am using the 3CSOHO100-TX card from 3Com and the 3c59x driver
> > for it. The card is a 10 / 100 Mbps card, yet when I connect its output to
> > my (Motorla) cablemodem (which should at most require 10 Mbps, right?), I
> > have problems with it. If the insmod is done with no options, I see an
> > error free interface reported by ifconfig, but the number of collisions
> > are non-zero.
>
> Why is that a problem? Collisions ("contention events") are normal with
> Ethernet.
>
> > If I insmod with full_duplex=1, then there are no collisions
> > reported, but I get a huge number of recieve frame errors.
>
> This is exactly what you would expect with a duplex mismatch.
> Forcing full duplex is almost always a mistake.
>
> > Is this a
> > problem card (i.e. should I get another card type) or am I doing something
> > wrong?
>
> Unless there is some problem you haven't reported, the system was
> working correctly.
>
>
> Donald Becker becker@scyld.com
> Scyld Computing Corporation http://www.scyld.com
> 410 Severn Ave. Suite 210 Second Generation Beowulf Clusters
> Annapolis MD 21403 410-990-9993
>
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