Multicast Routing Source-based trees Shortest path trees Shortest path tree from the source to all destinations using Dijkstra's Algorithm. Impractical in practice because of the need to consider the entire topology between source and destinations. Some packets will travel down subtrees with no destinations attached. A prune packet is sent by a leaf router to cut off subtrees without destinations.
Initial packets are data packets that are flooded to all multicast routers.
The intermediate routers that have already received this packet sends a prune to the router which sent the duplicate packet. The leaf routers that are not interested in this data packet because there are no destinations listening on that group address sends a prune message to the sending router. PIM-Dense Mode Not dependent on any underlying protocol. Uses group-shared tree with root domain Shared trees Steiner Tree Minimum spanning tree connecting all routers with attached group members. Too costly in practice.