In PIM-SM, how does a router actually becomes a rendezvous point ?
Routers must be configured manually to be a candidate RP. One router in each PIM domain is elected by the other RPs to be the Bootstrap Router (BSR). The BSR floods messages announcing all of the suitable RPs (the RP-set) throughout the domain, so that all routers know the addresses of the RP-set. The RP can also be specified manually, which makes sense for a small domain with only a few routers. Note that a router can be set up to be a RP for only a subset of Class D group addresses. You could, for example, configure one of your routers to be a RP only for the groups that you were going to participate in. • What is Source Specific Multicast ? Source Specific Multicasting (SSM) uses the capabilities of IGMP v3 to tune PIM-SM to the needs of large scale, one-to-many, webcasting. IGMP v3 allows a source to explicitly request traffic from a particular (S,G) pair, through an INCLUDE report. In SSM edge routers must be modified to generate a PIM-SM SPT (S,G) join directly from a IGMP v3 INC
