A Review of Incentive Mechanism in Peer-to-Peer Systems

Free riders in the peer-to-peer (P2P) networks are nodes that only consume services but provide little or nothing in return. They seriously degrade the fault-tolerance, scalability and content availability of the P2P systems. The solution to free riding problem in P2P networks is to have incentive mechanisms that aim to improve the network utility by influencing the nodes to be more cooperative. This paper proposes five design requirements that an incentive mechanism should satisfy and suggests that the existing incentive mechanisms can be classified into three categories: monetary-based, fixed contribution and reciprocity-based schemes. The paper outlines the principles, provides typical examples and applications and discusses limitations of these schemes. The applicability of each scheme is also discussed against the proposed deign requirements. The aim is to provide an overview and guidance to enhance the applicability of incentive mechanisms in P2P systems.