3c996

[jim fixit]

Has anyone worked with this card? Are you aware of any settings to turn
off early transmit or does it even support that feature?

We have nw6 sp3, using an old 3c985 gb fiber nic. Server is really
slow. Examining packets I can see that they get smaller in size and
fewer in number prior to acks coming back, but the sliding window value
does not change so I don't know what would make the server do this.

Anyway, since the 3c985 is old and has no driver for nw6, we are in fact
using the 3c996 driver for it, I decided to replace that card and see if
it would help. The current available option seems to be the 3c996.
But I've read that the problem we have can also be caused by the 'early
transmit' feature of some of the 3com cards. I don't see in my
documentation that either the old 3c985 or this new 3c996 has such a
beast. Does anyone know how to turn that off if it does infact exist?

Maybe I don't need to replace my nic, maybe I just need to tell it not
to do that early transmit thing.

Ideas, comments? Anyone using 3c996 have recommendations for best
practices when setting it up?

[Marcel Cox]

Jim,

It is my understanding that the 3c996 cards are actually cards using
Broadcom gigabit chips and using the standard b57.lan Broadcom driver.
If this is the case, these cards will be quite different in architecture
from the "native" 3Com cards and the typical settings you may find for
3Com cards may not apply for Broadcom cards.

As for your actual problem, your vague description rather points to an
application level problem, or maybe the switch is dropping packets. I have
the impression the card might not the real source of your slowness.

Maybe a more detailed descriptions of your whole configuration, and the
tests you did to analyse your slowness might be of help to diagnose the
problem.

--
Marcel Cox
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[jim fixit]

Marcel

Thanks for that input. Yeah it was the Nic, which I was fairly sure of.
Basically folks going into that server using that nic were dog slow,
but if I put the same workstations on another segment (thus using
another nic into the server) the response was cut to 1/4 of the time for
the same operations. I could see in the packet traces that as long as a
user was going in through the old GB nic the packets were small and
numerous whereas going in via the other nic, they were large and
efficient. Replacing the nic solved the issue. However, you are right
about the 3c996...it does use B57 and Broadcom chip set and, my compaq
didn't like it one bit. Broadcom makes the chip set on Compaq (oh, I
mean HP's) latest GB nics but, the q57 driver won't load either. I
ended up sending 3c3996 back and buying a bonafide compaq card which
worked fine. Yesh! But all's well that ends well, users are happy,
that's the finish line.

[Marcel Cox]

Jim,

I'm glad you found a workaround for your problem.
Thanks for the report back.