A dynamic model of BitTorrent-like P2P file-sharing system

With the popularity of the P2P applications in the Internet, the study of the P2P file-sharing system becomes more important. BitTorrent is a preliminary and the most successful P2P file-sharing application in the Internet, and has all the typical characteristics of the P2P file-sharing systems. In this paper, we propose a dynamic model of BitTorrent-like P2P File-Sharing System. The model describes the P2P file-sharing system in the microcosmic view by defining a novel state. The state is used to describe the evolution of the interaction between peers of the system. Through the model, we will know how some central policies influence the system. These policies include peer selection policy, piece selection policy, bandwidth allocation policy and peer choking policy. Finally, some experiments are designed to validate the model.