By nature, a hub is half-duplex - it's a repeater.

Besides, misconfigured duplex will not cause CRC errors.

C.

-----Original Message-----
From: David G. Andersen [mailto:dga@lcs.mit.edu]
Sent: Tuesday, January 07, 2003 2:08 PM
To: Drew Weaver
Cc: 'nanog@merit.edu'
Subject: Re: Weird networking issue.

Rule number 1 with any ethernet:  Check to make sure you have the duplex
and rate statically configured, and configured identically on both ends of
the connection.

I'd wager you've got half duplex set on one side, and full on the other...

  -Dave

On Tue, Jan 07, 2003 at 02:19:10PM -0500, Drew Weaver mooed:
>
> Hi, this is kind of a newbie question but this doesn't make a whole lot of
> sense :P
>
> I have an etherstack hub connected to a FastEthernet port on a cisco 3660
> router, these are the stats when I do a show int fast0/0:
>
> 5776 input errors, 5776 CRC, 2717 frame, 0 overrun, 0 ignored
>
> Whats weird is I just cleared the counters 12 minutes ago, and already there
> are almost 6000 CRC errors. This connected via a standard Cat5 ethernet
> cable, I have tried replacing the cable to noavail.
>
> Is this a fairly normal situation, If so that's great, but it seemed rather
> ridiculous to me, and if it is not a normal situation, what would cause
> this?
>
> Any ideas are appreciated.
> Thanks,
> -Drew Weaver

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