Designing Cisco Enterprise Networks (ENSLD) — Question 222

What are two purposes of the RPF check in multicast routing? (Choose two.)

Answer options

• A. to ensure that multicast packets are forwarded if they arrived on the interface used to route traffic back to the source address
• B. to ensure that multicast packets are forwarded if they arrived on the interface used to route traffic to the destination address
• C. to ensure that multicast packets are dropped if they arrived on the interface used to route traffic to the destination address
• D. to ensure that multicast packets are dropped if they arrived on the interface used to route traffic back to the source address
• E. to ensure that multicast packets, no matter the interface they arrived on are forwarded out all interfaces

Correct answer: A, C

Explanation

The correct answer is A and C. Option A is correct because the RPF check ensures that multicast packets are appropriately forwarded back to the source address. Option C is accurate as the RPF check also ensures that packets arriving on the wrong interface, which is used to route traffic to the destination, are dropped. Options B, D, and E do not correctly describe the functions of the RPF check in multicast routing.