What is PGM?
- Reliable multicast transport protocol
- NACK based with suppression
- Lost packets are retransmitted only to NACKers (unicast)
- PGM guarantees loss detection and recovery (in most of the cases), ordered, duplicate-free data transmission
- It’s simple, scalable and it makes routers more intelligent (but needs faster routers, no security)
University College London - Pragmatic General Multicast