An analytical study of peer-to-peer media streaming systems

Recent research efforts have demonstrated the great potential of building cost-effective media streaming systems on top of peer-to-peer (P2P) networks. A P2P media streaming architecture can reach a large streaming capacity that is difficult to achieve in conventional server-based streaming services. Hybrid streaming systems that combine the use of dedicated streaming servers and P2P networks were proposed to build on the advantages of both paradigms. However, the dynamics of such systems and the impact of various factors on system behavior are not totally clear. In this article, we present an analytical framework to quantitatively study the features of a hybrid media streaming model. Based on this framework, we derive an equation to describe the capacity growth of a single-file streaming system. We then extend the analysis to multi-file scenarios. We also show how the system achieves optimal allocation of server bandwidth among different media objects. The unpredictable departure/failure of peers is a critical factor that affects the performance of P2P systems. We utilize the concept of peer lifespan to model peer failures. The original capacity growth equation is enhanced with coefficients generated from peer lifespans that follow an exponential distribution. We also propose a failure model under arbitrarily distributed peer lifespan. Results from large-scale simulations support our analysis.