Debt-based file exchange mechanism in peer-to-peer networks

The self-interest of peers degrades the system usability of P2P file sharing networks. Debt-based files exchange network constructs an incentive mechanism which induces cooperative and equivalent file exchange where creditor´s rights between neighbors play as light weight cash in file download. Creditor´s rights need only be maintained between neighbors, so maintenance cost is low and the mechanism is scalable for large networks. Number of files shared can be seen as a peer´s strategy selection. The game among rational peers exists a Nash equilibrium and the approximate algorithm of strategy selection gradually converges. Simulations indicate the effectiveness of incentive mechanism and steady performance in dynamic networks.