Feedback-Free Multicast Prefix Protocols

Developing scalable, reliable multicast protocols for lossy networks presents an array of challenges. In this work we focus on scheduling policies which determine what data the sender places into each sent packet. Our objective is to develop scalable policies which provably deliver a long intact prefix of the message to each receiver at each point in time during the transmission. To accurately represent conditions in existing networks, our theoretical model of the network allows bursty periods of packet loss which can vary widely and arbitrarily over time. Under this general model, we give a proof that there is an inherent performance gap between algorithms which use encoding schemes such as forward error correction (FEC) and those which do not. We then present simple, feedbackfree policies which employ FEC and have guaranteed worstcase performance. Our analytic results are complemented by trace-driven simulationswhich demonstrate the effectiveness of our approach in practice