In an anycast RP environment, multiple Rendezvous Points (RPs) share the same IP address to provide redundancy and load balancing. A source's Designated Router (DR) will only register the source with its topologically closest RP. To ensure all RPs in the anycast set are aware of all active sources, a source-sharing mechanism is required.

Junos OS supports two primary methods for this:

1. MSDP (Multicast Source Discovery Protocol): RPs are configured as MSDP peers. When an RP learns of a new source, it sends a Source-Active (SA) message to its peers, informing them of the active source.

2. Anycast PIM: Using the rp-set statement, RPs within the set use PIM messages to exchange source registration information directly.

Both solutions are configured on the RP routers.

C. The rp-set statement is configured on the RP routers to define the anycast set members, not on the source DRs.

D. MSDP is a protocol that runs between RPs to share source information; it is not configured on source DR routers.

1. Juniper Networks TechLibrary. (2023). Understanding Anycast RP for PIM. Junos OS Documentation. Retrieved from https://www.juniper.net/documentation/us/en/software/junos/multicast/topics/concept/multicast-anycast-rp-understanding.html. In the "Anycast RP Methods" section

it states: "To enable anycast RP

you must configure the address of all the RPs in the anycast RP set. You can do this in one of two ways: ... Configure the rp-set statement on each RP router in the anycast-RP set. ... Configure Multicast Source Discovery Protocol (MSDP) on each of the RP routers in the anycast-RP set."

2. Juniper Networks TechLibrary. (2023). Example: Configuring Anycast RP. Junos OS Documentation. Retrieved from https://www.juniper.net/documentation/us/en/software/junos/multicast/topics/example/multicast-anycast-rp-configuring.html. This document provides a configuration example showing the rp-set statement configured under the [edit protocols pim rp] hierarchy on the RP routers.

3. Juniper Networks TechLibrary. (2023). MSDP Overview. Junos OS Documentation. Retrieved from https://www.juniper.net/documentation/us/en/software/junos/multicast/topics/concept/msdp-overview.html. The overview states

"MSDP is also used for anycast RP

which is a way to provide RP redundancy and load sharing." It clarifies that MSDP peering is established between RPs.