[c-nsp] sup32/sup720 onboard int performance

[Jeff Bacon]

How are the ports that are on the supervisor module hooked into the
fabric/PFC? Are they at any significant advantage or disadvantage
compared to ports on linecards? 

I'm primarily wondering because I'm wondering about the performance of
sup32s. I understand that any linecard is going to be running on
classic-bus with a sup32, and that probably adds a couple usec of
latency vs fabric-switched packets. And I've seen various documents on
how the various linecards are architected. But I've never seen anything
describing how the onboard ports are dealt with. Are they operating as
if they're on a fabric-connected linecard? Are their controllers
directly hooked into the PFC? Or are they abortions just stuck on there
for the sake of argument? 

I have various use cases where a pair of sup-32s in a 6503 chassis makes
plenty of sense for what I need. I have a couple, and they're ok so far
- but I have yet to really stress them out at all either. 

Thanks,
-bacon