What mechanism does PIM use to forward multicast traffic?

What mechanism does PIM use to forward multicast traffic?
A . PIM sparse mode uses a pull model to deliver multicast traffic.
B . PIM dense mode uses a pull model to deliver multicast traffic.
C . PIM sparse mode uses receivers to register with the R
E . PIM sparse mode uses a flood and prune model to deliver multicast traffic.

View Answer

Answer: A

Explanation:

PIM dense mode (PIM-DM) uses a push model to flood multicast traffic to every corner of the network. This push model is a brute-force method of delivering data to the receivers. This method would be efficient in certain deployments in which there are active receivers on every subnet in the network. PIM-DM initially floods multicast traffic throughout the network. Routers that have no downstream neighbors prune the unwanted traffic. This process repeats every 3 minutes.

PIM Sparse Mode (PIM-SM) uses a pull model to deliver multicast traffic. Only network segments with active receivers that have explicitly requested the data receive the traffic. PIM-SM distributes information about active sources by forwarding data packets on the shared tree. Because PIM-SM uses shared trees (at least initially), it requires the use of an RP. The RP must be administratively configured in the network.

Answer C seems to be correct but it is not, PIM spare mode uses sources (not receivers) to register with the RP. Sources register with the RP, and then data is forwarded down the shared tree to the receivers.