[c-nsp] Layer 2 vs Layer 3 Performance Question

[Phil Mayers]

> 
> So the question is, is there a difference?  I have hundreds of GB's
> to backup so if there is a performance difference one way or the
> other, I would want to know.  The only thing I can see as a
> difference is if I trunk the iSCSI vlan, then the traffic never hits
> the 6509's routing module. Maybe that helps performance?
> 

If I've understood you correctly, then there's no difference - the 6500 
will forward 1gig layer2 just as quick as 1gig layer3.

There are some possible differences if the linecard does not have a DFC, 
or is a bus-linecard and the bus is contended; it would depend on what 
other traffic was flowing through the box.