Performance enhancement of pragmatic general multicast (PGM) protocol using a local loss recovery strategy

Reliable multicast is a technology used in a number of applications such as multi-receiver file transfer, streaming media, multimedia conferencing, collaborative processing etc. Pragmatic general multicast (PGM) is a reliable multicast transport protocol that runs over a best effort datagram service. Through this paper we propose an efficient loss recovery scheme for PGM. In our proposal a PGM router that receives a negative acknowledgement tries for local recovery prior to global recovery. The scheme works well when the sender/DLR is located further away from the PGM router than its receivers and the probability that a local receiver caches the packet is high. If there is a hit, the router retrieves the packet from its neighborhood, this results in a decrease in recovery latency, increase in throughput, reduction in power consumption also it alleviates the load at the sender/DLR.