CCNP Multicast and IPv6 Flashcards

What is the role of the Rendezvous Point (RP) in PIM Sparse Mode (PIM-SM)?

Answer: Acts as the meeting point where sources register and receivers join to establish multicast distribution trees

The RP in PIM-SM is the central point where sources register their multicast streams and receivers send join messages to form the shared tree.

Which protocol do hosts use to signal their membership in a multicast group to a local router?

Answer: IGMP (Internet Group Management Protocol)

IGMP is used between hosts and their directly connected multicast routers to report group membership and receive multicast traffic.

What is the multicast address range defined by IANA for general use?

Answer: 224.0.0.0 to 239.255.255.255

The full IPv4 multicast address range is 224.0.0.0 to 239.255.255.255 (Class D), though specific sub-ranges are reserved for link-local, global, and administratively scoped use.

What is the purpose of the RPF (Reverse Path Forwarding) check in multicast routing?

Answer: Ensures multicast packets arrive on the interface that the router would use to reach the source, preventing loops

RPF check prevents multicast routing loops by only accepting multicast packets that arrive on the correct upstream interface toward the source.

What is Source-Specific Multicast (SSM)?

Answer: A multicast model where receivers specify both the group address and the specific source they want to receive from

SSM uses the 232.0.0.0/8 address range and allows receivers to specify the exact (S,G) source-group pair, eliminating the need for an RP.

What is Auto-RP and what problem does it solve in PIM-SM networks?

Answer: A Cisco-proprietary mechanism that dynamically announces and discovers RP information, eliminating static RP configuration

Auto-RP uses Candidate-RP announcements sent to 224.0.1.39 and RP-Discovery messages at 224.0.1.40 to dynamically distribute RP information across the network.