Currently we have multiple LAN segments/sites with only unicast routing enabled between them, mostly via DMVPN (GRE) tunnels on the router(s). Multicast routing is disabled on the routers, and local Layer 2 multicasting is used by a seperate 3com NBX phone system in each local LAN.
What we'd like to do is enable SOME of the multicast traffic to travel over the VPN tunnels to SOME remote sites; but still isolate the multicast traffic from the other sites. Especially isolate the different sites with overlapping multicast traffic and address ranges; as it would most certainly be a 'bad thing' if the isolated local phones systems suddenly could hear each other's multicast traffic, which is supposed to only be 'local'.
How would we go about forwarding this multicast traffic to some of the remote sites (the ones without a local phone system), while still isolating the other LAN networks?
As a better example of what we want to enable; there is a 'tunneling' program available which simply listens for the local multicast data (244.0.1.59 port 2096) and forwards it to a 'receiver' at a remote location. However we don't want to have to rely on a computer running tunneling software, when I suspect something in the Cisco Routers can do the forwarding we need.
