Reverse Path Multicast (RPM)
Setup broadcast tree (reverse path broadcasting, RPB)
- Each node maintains “parent” and “child” links
- If packet from parent (“reverse-path check”) send to children; else drop
- If child is actually downstream (eg in terms of the routing metric), remove the child link
Truncated RPB (TRPB): Truncate leaf if IGMP says that there are no receivers for the group.
Reverse-Path Multicasting (RPM): truncate branch if IGMP says that there are no receivers for the group