A transport protocol supporting multicast file transfer over satellite links

The protocol is applicable to multicast file transfer over satellite links, but is also suitable for use in order broadcast networks. The OSI standards for the transport layer and for file transfer (FTAM) at the application layer have been used as models for the protocol. The transport protocol is based on a selective-repeat strategy for error recovery. The advantage of this strategy is that the protocol can handle the transfer in two phases. In the first phase the whole file is transmitted as a continuous stream of packets, and the sender just collects negative acknowledgements from receivers that lost packets. After that the sender enters the retransmission phase where the NACKed packets are retransmitted. The ´clever´ receivers that have not lost any packets can deliver the complete file after the first transfer phase.<>