A study of proactive hybrid FEC/ARQ and scalable feedback techniques for reliable, real-time multicast

In this paper, we examine the performance benefits of using parity encoding for reliable delivery of data to multiple receivers, where the receivers h ave heterogeneous loss and delay characteristics. First, we examine the eff ect of sending parity loss repairs proactively to receivers before it is kn own whether or not the repairs are needed to repair losses. We show that in many cases, proactive repair can reduce feedback implosion and the expecte d delay of reliable delivery without increasing bandwidth usage. Next, we e xamine how proactive repairs can be used to meet end-to-end deadlines to wi thin a tunable probability. Last, we examine several receiver feedback mech anisms for parity repairs in a heterogeneous networking environment, and fi nd that the various mechanisms offer different levels of robustness. Our ex aminations take into account temporally correlated (bursty) loss, as well a s loss of feedback messages from receivers. (C) 2001 Elsevier Science B.V. All rights reserved.