200-301 Question 110
Select 3A network engineer is implementing multicast routing on a network to support video streaming. The engineer has configured the routers with Protocol Independent Multicast (PIM) in Sparse Mode. However, users report that they are not receiving multicast traffic. Upon investigation, it is found that the multicast source and receivers are in different networks. Which of the following steps should the engineer take to resolve the issue?
- A
Configure an RP (Rendezvous Point) for the multicast domain.
- B
Enable IGMP snooping on all switches in the network.
- C
Ensure that multicast routing is enabled on all routers.
- D
Verify that the multicast source is advertising its traffic to the RP.
- E
Implement a static multicast route between the source and receivers.
Show answer and explanation
Correct answers: A, C, D
Explanation
In PIM Sparse Mode, an RP is required to act as a meeting point for multicast sources and receivers. Multicast routing must be enabled on all routers to forward multicast packets, and the multicast source must register with the RP for the receivers to join the multicast group. IGMP snooping, while useful at Layer 2, does not solve the Layer 3 routing issue, and static multicast routes are not used in Sparse Mode.
- A. Correct.
Configuring an RP is necessary in PIM Sparse Mode to facilitate communication between multicast sources and receivers. Without an RP, multicast traffic cannot be routed properly.
- B. Incorrect.
While IGMP snooping optimizes multicast traffic at the Layer 2 level, it does not address Layer 3 multicast routing issues or the need for an RP in PIM Sparse Mode.
- C. Correct.
Multicast routing must be enabled on all routers in the multicast path to ensure proper forwarding of multicast traffic.
- D. Correct.
The multicast source must advertise its traffic to the RP in PIM Sparse Mode for the multicast receivers to join and receive the traffic.
- E. Incorrect.
Static multicast routes are not used in PIM Sparse Mode. Instead, the protocol relies on the RP and dynamically built multicast distribution trees.