Reliable Multicast Transport
Problems:
- Retransmission can make reliable multicast as inefficient as replicated unicast
- Ack-implosion if all destinations ack at once
- Source does not know # of destinations
- “Crying baby”: one bad link affects entire group
- Heterogeneity: receivers, links, group sizes
- Not all multicast applications need reliability of the type provided by TCP. Some can tolerate reordering, delay, etc
Egs: Scalable Reliable Multicast (SRM), Lightweight Reliable Multicast Protocol (LRMP), Reliable Multicast Transport Protocol (RMTP), Pragmatic General Multicast (PGM)