[c-nsp] Odd Etherchannel behavior between 7507 and cat 4006

[Gert Doering]

Hi,

On Tue, Apr 07, 2009 at 05:23:17PM -0400, Bill Wichers wrote:
> I typically set both ends (router and switch) of these links to 100/full
> since I've seen weird autonegotiation problems before. This works just
> fine for individual FE links, but as soon as I bring up the Etherchannel
> group both member links on the router end drop back to "unknown duplex"
> (which the switch says is 100/half), and I can't figure out why my
> "full-duplex" config entry on each port magically disappears as soon as
> the Etherchannel group is brought up. That's the weird problem I'm
> trying to figure out...

A switch connected to a PA-FE-TX will never be able to figure out the
duplex settings on the PA-FE - because the PA can't tell it.  So you'll
always have to manually configure both sides for the desired duplex 
settings.

Now, in your case, I think you'll need to do some experimenting

 - set the switch to 100/full, run cisco ping tests (1000+ packets)
 - set the switch to 100/half, run cisco ping tests (1000+ packets)

if you get packet loss, you have a duplex mismatch...

If the setup *works* when set to 100/full, I'd classify the "unknown duplex"
thing as an artifact on the 7500 - given that the PA-FE cannot autonegotiate,
maybe the high-level code is just telling this to you "we don't know what's
the underlying physics".

If the setup needs 100/half on the switch side, I'd open a TAC case.

gert
-- 
USENET is *not* the non-clickable part of WWW!
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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
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