[c-nsp] multichassis lacp

[Matt Buford]

There is a pretty good summary here:

http://www.cisco.com/en/US/tech/tk389/tk213/technologies_tech_note09186a0080094646.shtml

Of particular note (to me at least) is the limit on the number of
Etherchannels within a stack.  I've been trying to standardize on always
doing LACP to every single server, and I've looked into the idea of doing
dual 2960 or 3750 with all downstream servers (~48 or so) having 2x1gig LACP
bundles.  However, the 2970 can only do 12.  I recall seeing before that the
3750 had a low limit, but I see now on that page that it says it will do 48
with 12.2 or higher.  That might actually work out for what I want.

However, at this point I'm mostly headed down the road of using Nexus for
handling this anyway.  With the Nexus 5548/5596, you can do 24 fabric
extenders of 48 ports (1152 ports) and then do every one of them as a
port-channel.