In a PIM Sparse Mode (PIM-SM) domain, Anycast RP is used for load balancing and redundancy by configuring multiple RPs with the same IP address. However, for active multicast sources to be shared between RPs, an additional mechanism is needed since PIM-SM does not automatically synchronize sources between RPs.
Evaluating the Answer Choices
Option A: "Configure MSDP on each RP router." ✅
Multicast Source Discovery Protocol (MSDP) is required in an Anycast RP setup to share active source information between RPs.
MSDP allows RPs to exchange source-active (SA) messages, ensuring that multicast receivers in different regions can still receive traffic from sources registered with different RPs.
Juniper Documentation confirms that MSDP is used to synchronize active sources across multiple RPs in an Anycast RP deployment.
✅ This is a correct answer.
Option B: "Configure anycast PIM with the rp-set statement on each RP router." ✅ Anycast PIM allows multiple RPs to share the same IP address, and the rp-set statement is used to define the set of Anycast RPs.
This enables receivers and sources to register with the closest RP.
However, Anycast PIM alone does not share active source information between RPs; MSDP is still needed for that.
The combination of Anycast PIM (rp-set) and MSDP is the correct approach.
✅ This is a correct answer.