[c-nsp] Why hard-setting speed and duplex on Fast Ethernet is bad

[John Neiberger]

On Fri, Aug 20, 2010 at 11:54 AM, Heath Jones <hj1980 at gmail.com> wrote:
> Thats a very good point John!
>
> Any thoughts why a cat5 <5m non-erroring link with auto on both ends that
> negotiates 100/full would sometimes (once,twice per week) drop down
> (10/half) and then back up again shortly after?
> Forcing both ends 'fixes' it (stops the flaps).. Seen that one before?
>
> Cheers

I've never seen that exact behavior before. I would test the cabling a
couple of times to make sure everything was truly up to spec. I saw
something close to that recently, but the link itself wouldn't drop.
It was a little stranger than what you saw. In our case, it ended up
being a bad NIC module in this particular device. They replaced the
NIC and all is well.

John