300-420 Question #219: Real Exam Question with Answer & Explanation

Question

A network engineer must design an MSDP multicast solution to provide RP resilience in a network with two separate domains. Also, multicast sources and receivers must register with the local RP. Which solution must the engineer choose?

Options

• AConfigure the RP has value to 0, and traffic will route to the closest RP
• BConfigure the RP loopback interface with the same IP address/32, and traffic will route to the
• CConfigure the RP group ranges to split the multicast traffic, and traffic will route to the longest
• DConfigure the RP priority with the same value, and traffic will route to the closest RP

Explanation

{"question_number": 2, "question": "MSDP multicast RP resilience with Anycast RP", "correct_answer": "B", "explanation": "The solution described is Anycast RP with MSDP. In this design, multiple RPs in different PIM domains are each configured with the same /32 IP address on their loopback interfaces. Because it is a /32 host route, unicast routing (e.g., OSPF) causes each source and receiver to register with their topologically closest RP - this is the 'anycast' behavior. MSDP sessions are then established between the RPs so they can share source-active (SA) state, enabling receivers anywhere to learn about sources registered with any RP in the network. This provides both local registration (sources/receivers use the nearest RP) and RP resilience (if one RP fails, traffic is rerouted to the surviving RP with the same anycast address). Setting the RP hash value to 0 (A) or adjusting priority (D) relates to PIM BSR/Auto-RP election, not Anycast RP. Group range splitting (C) divides multicast traffic but does not inherently provide resilience.", "generated_by": "claude-sonnet", "llm_judge_score": 4}

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