If I use a router as my IGMP grouping/querier device at layer 3, will all multicast traffic go through the router's ethernet interface? This seems like it might be a problem, especially if the interface is 10Mb. This might prevent multicast traffic from going out all ports on a switch, but it's still all going to have to go through the router interface, isn't it?
For this reason, it seems like it would be a much better solution to use a L3 switch if I am going to do multicasting.
But I admit I do not know much about how multicasting works. Perhaps somehow the data would be directed to the appropriate IGMP listening ports without going through the router's interface?