%0 Journal Article
%T Evolutionary Game Theory-Based Evaluation of P2P File-Sharing Systems in Heterogeneous Environments
%A Yusuke Matsuda
%A Masahiro Sasabe
%A Tetsuya Takine
%J International Journal of Digital Multimedia Broadcasting
%D 2010
%I Hindawi Publishing Corporation
%R 10.1155/2010/369814
%X Peer-to-Peer (P2P) file sharing is one of key technologies for achieving attractive P2P multimedia social networking. In P2P file-sharing systems, file availability is improved by cooperative users who cache and share files. Note that file caching carries costs such as storage consumption and processing load. In addition, users have different degrees of cooperativity in file caching and they are in different surrounding environments arising from the topological structure of P2P networks. With evolutionary game theory, this paper evaluates the performance of P2P file sharing systems in such heterogeneous environments. Using micro-macro dynamics, we analyze the impact of the heterogeneity of user selfishness on the file availability and system stability. Further, through simulation experiments with agent-based dynamics, we reveal how other aspects, for example, synchronization among nodes and topological structure, affect the system performance. Both analytical and simulation results show that the environmental heterogeneity contributes to the file availability and system stability. 1. Introduction File sharing is one of key technologies for achieving attractive multimedia social networking. Each user treasures multimedia contents, for example, video and music, in his/her own terminal and they are shared with other users. Since the number of users continues to increase and user terminals become more heterogeneous with the development of mobile technologies, it is desirable to achieve file sharing in a form of peer-to-peer (P2P) systems, which are self-organized and scalable without any specific infrastructure. To realize effective P2P file-sharing, two key issues should be considered: User selfishness and heterogeneity. Since each node participating in the system is a user's terminal, it is controlled by the user. In general, each user is selfish and hesitates to actively share files due to costs for file caching, such as storage consumption, processing load, and bandwidth consumption [1]. On the other hand, the heterogeneity of user environments can be classified into self environments and surrounding environments. Each user potentially has a cooperative degree in file caching, depending on its terminal performance, access link capacity, and sense of value to the file, a On the other hand, the surrounding environment is represented as the connectivity relationship between nodes, which is determined by the topological structure of P2P networks. Each user has to determine its behavior so as to maximize its own benefit, taking account of the behavior of its
%U http://www.hindawi.com/journals/ijdmb/2010/369814/