Small Coalitions: Lightweight Collaboration for Efficient P2P Downloads

Peer-to-peer (P2P) architectures are gaining increasing popularity in disseminating content to a large number of nodes. In this paper, we show that small coalitions between peers can further enhance the performance of current P2P architectures. Small coalitions bridge the gap between inefficient non-cooperative and fully cooperative architectures by establishing a robust tradeoff between the complexity and performance of the resource distribution process. Owing to their small size, small coalitions are inherently resilient to the churn in existing P2P systems and embed natural incentives for peers to self-organize in order to improve their download times. We evaluate several coalition strategies analytically and empirically via simulations and we show that our solutions considerably improve the download performance in current P2P systems.