Multicast HostsNetworked Groups: Client/ServerNetwork HostsMulticast Routing: An Introduction to Protocol Independent Multicast and Multicast TreesSeeing the Forest Through the TreesConcepts of PIM Group StatesTwo Types of TreesPIM NeighborsPIM Messages: Join, Leave, Prune, Graft, and AssertPIM ModesPIM Dense-ModePIM Sparse-ModePIM Sparse-Dense ModeMulticast Flow at the LeafThe Rendezvous Point and Shared Tree DynamicsBuilding the Multicast Routing Information BasePIM-BiDirPIM-SSMSummary