6509 Core /w Sup 720
Edge Switches - 3560's w/ IP Services image
FWSM doesn't support multicast routing in multiple context mode
3560 doesn't support GRE Tunnels
I have a multicast sources directly connected to a 6509. I've configured multicast routing and have it working successfully for edge campuses that use ASAs for their firewall. Other campuses use a FWSM in the 6509 and have no ASA. They only have a 3560 at their site. Several VLANs are trunked from the 6509 to the 3560, routing first through the FWSM. For these sites I'm unable to get multicast routing to work. TAC informed me that the FWSM doesn't support multicast routing. I figured as much after the commands from the configuration guide weren't available in any of the FWSM contexts, even the admin context. TAC then suggested using GRE Tunnels to tunnel multicast traffic through the FWSM. This isn't an option as the 3560's at the edge don't support GRE.
I tried to route around the FWSM by creating another VLAN that trunks from the 6509 to the 3560 but doesn't pass through the FWSM. This would work, but I have overlapping networks hanging off the 6509 (not by choice and not something I can change - I'm looking for options *other* than re-ip'ing these networks). After trying to get a NAT configuration that would alleviate the overlapping IP address issue I was unsuccessful. Admittedly weak in IOS NAT'ing, I think the problem lies with the fact that two different interfaces have identially IP'd networks. This doesn't cause me a problem when going through the FWSM obviously, but does cause a problem when I route around it.
Are there any alternative solutions I haven't tried yet?
I need the multicast source(s) on the 6509 to reach devices at the edge, connected via trunk links and 3560's. Presumably this must be done via multicast routing.