How does it work…cont?
- So only one instance of NACK is forwarded
- Retransmitted packets are forwarded only by routers that have already built these retransmit states otherwise discard it
- PGM specifies three ways the missing data can be supplied in response to a NACK: from the original source, another receiver or from a DLR (Designated Local Retransmitter)
- Flow control :The window size increases whith absence of NACKs or simply with the passage of time
University College London - Pragmatic General Multicast