Having read the white paper http://www.cisco.com/en/US/partner/prod/collateral/switches/ps5718/ps708/prod_white_paper0900aecd80673385.html
I'm still unsure how the following scenario works:
Imagine a scenario with two 6500 chassis - switch A and switch B, both with Sup720 engines, both with line cards with no DFC boards (for example WS-X6748-GE-TX). There is a trunk between the two switches so devices on one switch can communicate with devices on the other.
Both switches / Sup720 modules have synchronised L2 VLAN databases. On top of this, both switches also have a L3 VLAN interface declared. HSRP is used to define switch A as the priority switch, with the Sup720 of switch B becoming the active routing engine should switch A fail.
From the white paper, I see how packets which enter a port which has no DFC need to be managed by the Sup720.
Questions are: for traffic entering switch B, does the supervisor of switch B manage the forwarding or does the Sup of switch A have to do it (because it is the running L3 router)?
Question for both L2 traffic on the same subnet and L3 traffic where routing is required (presumably via Sup720 of switch A).
Does the location of the destination port have any impact; is the behaviour different if the destination port is on switch A or B ?