What is the command to set PIM mode on an interface?

The command to set Protocol Independent Multicast (PIM) mode on an interface is "ip pim sparse-mode." This command configures the interface to operate in sparse mode, which is one of the modes of PIM. Sparse mode is designed for scenarios where receivers are not present in all parts of the network. In this mode, multicast traffic is only sent to those parts of the network that have subscribed to the multicast group, thus conserving bandwidth and reducing unnecessary traffic.

Choosing sparse mode allows for efficient multicast routing because it establishes a shared tree and manages the distribution of multicast data based on the presence of receivers rather than flooding the network with multicast packets. It works well in scenarios with geographically dispersed receivers.

Understanding the specific function of sparse mode helps in designing multicast networks efficiently, especially in larger or more complex topologies where targeted multicast delivery is crucial. Other command options either do not configure an interface for PIM mode or represent incorrect syntax and concepts related to how PIM operates.