A Coalition based Incentive Mechanism for P2P Content Distribution Systems

Abstract

P2P systems suffer from free-loaders, peers that consume many more resources or contents (bandwidth) than they contribute. One of the reasons for this is that the mechanisms used for downloading and sharing in the P2P systems, do no take selfish behavior of the peers into account at the design stage. Therefore, it is important to find mechanisms that provide incentives and encourage cooperative behavior among the peers. One possible solution could be to use an economic framework that provides them with incentives. We propose the application of a coalition formation scheme based on game theory to P2P file sharing systems. The main idea for the coalition formation scheme is based on the fact that peers that contribute more get a better quality of service. A peer that participates in a coalition lends ”bandwidth” to other peers of the coalition, in exchange for utility and consequently far greater download bandwidth. Simulation results have shown the effectiveness of the mechanism in stopping the free-riding peers and encouraging cooperation, increasing the performance of a P2P network and obtaining an improvement in time download performance.