I'm on an isolated (for now) catalyst 3560e. I have a multicast source, which when enabled, causes flooding to all switch interfaces. I have a second different multicast source, which does not cause flooding, it only gets delivered to the sinks who request it.
The second case leads me to believe the switch IGMP is configured properly, but what could be different about the first stream? I thought multicast/IGMP was 'I only get the stream if I ask for it'.