Balancing throughput, robustness, and in-order delivery in P2P VoD

Peer-to-peer has emerged in recent years as a promising approach to providing Video-on-Demand streaming. The design space, however, is vast and still not well understood---yet choosing the right approach is critical to system performance. This paper takes a fresh look at the p2p VoD design space using a simple analytical model that focuses on the allocation of uplink bandwidth resource for different chunks across peers. We describe a fundamental tradeoff that exists between system throughput, sequentiality of downloaded content and robustness to heterogeneous network conditions and node capacities, and we prove that no system can achieve all three simultaneously. Empirical results from Emulab confirm the analysis and show how one might implement efficient peer-to-peer VoD streaming with an appropriate balance of the tradeoff.