Protocol Independent Multicast (PIM)
PIM is a protocol used between routers to keep track of where to forward
traffic for each multicast group. It can use information gathered from any
routing protocol. PIM can run in dense mode or sparse mode.
PIM Dense Mode
PIM dense mode uses source-based trees. When running in dense mode,
PIM assumes that every router needs to receive multicasts. Any router that
doesn�ft want to receive it must send a prune message upstream to the server.
PIM dense mode is most appropriate when:
�¡ Multicast servers and receivers are near each other.
�¡ There are just a few servers and many receivers.
�¡ You have a high volume of multicast traffic.
�¡ The multicast stream is fairly constant.