[c-nsp] port channel

[James Saker]

Found a solution - thanks to many great suggestions here (thank you all!). 

Indeed the issue was on the Cat5500 side which appears to be somewhat fussy
on how Etherchannel is implemented, especially with a router. Here's a
summary of was necessary to get Etherchannel operating between a 7500 (7507
in this case) and a Catalyst 5500:

o keep on the same blade on the Catalyst 5500. 4/1-2 or 7/1-2 works fine.
4/1 and 7/1 does not (I also tried 4/1,7/2 per the even/odd discussion; no
go!). Scott Keoseyan's comments about the design helped greatly here.

o use even/odd combos e.g. 4/1 and 4/2. 

o mirror port configurations before trying to bring into Etherchannel.
Duplex, VLAN, queuing and other mismatches will prevent them from coming
together. When in doubt, or when fighting a pesky trunking situation, clear
config all is a good starting point for a lab setup.

o set port channel #/# mode on  --> this was necessary given the router
won't speak PAgP (again thanks to Scott and a few others with this
recommendation). 

The result should be an active Etherchannel definition in show port channel
info.

Jamie