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

[Adam Armstrong]

Lee wrote:
> My experience has been that setting the speed and duplex on a catalyst
> switch stops it from doing auto-negotiation.  So with the switch ports
> set to 100/full I'd expect the 7500 ports to come up as 100/half.  But
> we don't have any cat4006s at work.. I don't know if they do
> auto-negotiation even if the port speed and duplex is configured,
>   
Setting duplex disables autonegiotation (setting speed doesn't disable 
duplex negotiation). When you force duplex on a port, the port stops 
participating in the autonegitation and forces itself to the setting you 
give it. This causes the opposite port (if it's autonegotiating) to drop 
always to half duplex.

As a general rule, you shouldn't force the duplex on a port unless the 
autonegotiation fails! (as it does on some quite old hardware)

adam.