[c-nsp] Multicast clarification

[Martin Barry]

Just trying to understand a traffic pattern and my Google-fu is failing to
turn up anything that covers this query.

Scenario:

- 3750 stack with 2 members
- 2 routers forwarding different multicast streams into the same VLAN

The switch correctly shows both routers:

#sh ip igmp snooping mrouter 
Vlan    ports
----    -----
   4    Gi1/0/25(dynamic), Gi2/0/25(dynamic)


The switch will take multicast traffic from router A and forward it to those
ports where it has snooped an IGMP join. It also appears to forward the
multicast out router B's port.


Questions:

Is this correct? Is multicast forwarded out all mrouter ports on the same
VLAN except the ingress port? Is there a way to prevent this from happening?

cheers
Marty