Optimal Cache Allocation and Probabilistic Caching for Local Loss Recovery in Reliable Multicast

Local loss recovery for reliable multicast can provide significant performance improvement in terms of loss recovery latency, bandwidth consumption and network throughput. In this paper, an analytical model for studying the optimal cache allocation for ARM is constructed. Using standard optimization techniques, the optimal cache allocation pattern can be found. Our numerical results show that using optimal cache allocation yields significantly smaller loss recovery latency than using uniform cache allocation. To further enhance the loss recovery performance when the amount of cache at an active router is limited, we propose a probabilistic caching policy. We derive the optimal caching probabilities for each active router in a given multicast tree with a given cache allocation pattern. We show that with the use of probabilistic caching policy, a further reduction in loss recovery latency can be obtained.