Stochastic Differential Equation Approach to Model BitTorrent-like P2P Systems

In this paper, we propose to model the dynamics of BitTorrent (BT) P2P file sharing systems using the stochastic differential equation method. Unlike previous approach, our method can capture more realistic network environment and peers behavior. Closed-form solutions of various performance measures such as the average number of downloaders, seeders, the system throughput and file downloading time are derived. We also validate our mathematical results via simulation and show that not only our mathematical model can closely track the dynamics of BT-like systems, but the model has a much higher accuracy than previous proposed methods. Also, many important properties can be derived from the close-form solution such as performance scalability, sensitivity of the measurements to various system parameters. We believe the proposed method can provide better understanding in the design and analysis of BT-like P2P systems.