I have one question related to a scenario similar to the topology shown early in this article with the multicast router.
Assume you still have the source, various L2 switches as shown, and the router R1, however the receivers for the multicast receivers are actually on the far side of R1. Assume there are one or more routers connected to R1 that are not shown. The receivers we are concerned about are connected to those routers. A loopback on R1 is configured as the RP for the multicast group(s) in question.
How does SW1 know to forward the multicast traffic out Fa0/1 to R1 in this case? What configuation is required?
Is the multicast traffic inherently forwarded to the multicat router/querier?
Every article I can find either discusses how IGMP is handled in a L2 broadcast domain, or demonstrates how PIM joins enable multicast traffic to flow from the FHR. I haven’t been able to find any good explanation concerning the behavior when you combine PIM on downstream routers, and one or more L2 switches between the multicast source and the first hop router.