When using the BSR mechanism for RP distribution, which router component aggregates candidate-RP advertisements and distributes the RP-set to all PIM routers?

The Bootstrap Router (BSR) is the central component in the BSR mechanism for PIM-SM RP distribution. It collects Candidate RP (C-RP) advertisements, selects the best C-RPs based on their priority, and then distributes this RP-set information to all PIM routers in the domain. This ensures all routers know which RP to use for specific multicast groups. BFD (Bidirectional Forwarding Detection) is a fast failure detection protocol and is unrelated to RP distribution. A Mapping Agent is a term sometimes used in other multicast contexts but not specifically for the BSR mechanism. A Candidate RP (C-RP) advertises its willingness to be an RP, but it doesn't aggregate or distribute the RP-set; that's the BSR's role.