A Super Node Monitoring-based Mechanism For Combating Free Riding In Peer-to-peer Networks

With the rapid development of Internet, the application of P2P technology is more and more extensive, and the scale of the network is larger than ever before. Therefore the problem of fair resources sharing in peer-to-peer system has become more and more serious. P2P is one of the most popular technologies in the Internet. It provides an open, free file exchange environment. These features make a considerable portion of peers in P2P networks only obtain services provided by others, but not contribute to the whole system. This selfish behavior of peers is called free riding and the selfish peers are regarded as free riders. Free riding is a great challenge to P2P systems. It is a severe threat to the availability, quality of service, expandability and robustness of P2P network. If this phenomenon is too rampant, the entire P2P system may even collapse eventually. Therefore, the rational P2P application developers should develop some anti-free riding measures to deal with it.In this paper, we propose a super node monitoring-based mechanism (SNMM) against free riding that will alleviate the problems associated with free riding and make P2P network more robust and stable. (1) According to the behavior and function of nodes, the P2P network is abstracted to be a Super-Node hierarchical structure to monitor the behaviors of nodes focusing on avoiding dishonest behaviors and malignant cheating. (2) The number of users is used as the premise to trigger the mechanism in order to facilitate the business applications on the network. (3) The definition of Enjoy Service Ability is involved to measure the contribution of peers to the whole system, which is based on the number of provided files, the size of provided files and the quality of provided files. (4) Nodes are reward and punished by distributing and maintaining a permit mechanism. (5) Provide service Availability and Feedback Credibility is imported to guarantee the quality of services. (6) Propose a scheme to combat Whitewashing problem. Finally, the simulation results verify the effectiveness and feasibility of this model.