Research On Node State-based Incentive Mechanism In P2P Network

Peer-to-Peer (P2P) has become the overwhelming technology for the Internet as its benefits over traditional client-server approaches to cooperative working, data sharing and large scale parallel computing. The basic assumption of P2P networks is that peers are willing to share resources with others. However, the reality is that the private provision of public goods causes free-riding and the tragedy of the commons in P2P networks. In fact, the rational users of P2P networks are self-interest and self-determination. The object of them is to maximize the personal utility without considering the whole network productivity. In addition, there still exist a large amount of P2P services with unreliable qualities and malicious actions. Therefore, to improve the performance of P2P networks, the peers' voluntary operations must be taken into account as well as the incentive mechanism which incentive peers cooperate and consume resources rationally. This dissertation studies the problems of unreliable services and incorporation in P2P networks, and results in the following achievements:First, how to design systemic node state model is studied. The outstanding works in the research field about node behaviors have been analyzed and compared in this paper, and state model is chosen to model nodes behaviors. Node State model takes trust and contribution two behavior characteristics of nodes into account, classifies multi-states, design a series of transition primitives and rules, at last presents the process of states transition in DFA.Secondly, how to design a Node State-based adaptive topology protocol for file-sharing P2P network is studied. We construct the protocol by defining two kinds of Primitives based on KQML and specifying three Mechanisms in ECA to implement those Primitives. It takes trust and contribution two behavior characteristics of nodes into account while forming connections. Integrating the strongpoint of NS model and supplementing with Response Choosing mechanism, NS-ATP provides incentive to cooperative nodes and forms impartial topologies. Thirdly, how to design a service differentiated incentive mechanism based on Node State model is studied. In order to provide incentive and service differentiation, we design SDI strategy that nodes in restrained state group will be punished in different way and in unrestrained state group will compete for resource. Integrate the strong points of both NS model and NS-ATP, NS-IM provides different quality service to nodes according to their state.Finally, an example which explains the implement of NS-IM and an emulation experiment which validates NS-IM's feasibility and validity are presented.Our research aims to carry out a service differentiated incentive mechanism based on Node State model, and the experimental result shows that the proposed incentive mechanism can effectively provide differentiate services and encourage nodes to share resources, thereby improving the system performance.