On the Service Capacity of P2P Systems

One of the most fundamental problems in the realm of peer-to-peer systems consists of determining their service capacity. In this paper, we first propose a new Markovian model to compute the throughput of peer-to-peer systems. Then, we present a simple approximate model for obtaining the system throughput for large peer populations. From the models, we obtain novel insights on the behavior of P2P swarming systems which motivate new mechanisms for publishers and peers to improve the overall performance. In particular, we show that if publishers adopt the most deprived peer selection, and peers reduce their service rate when they have all the file blocks but one, the system's capacity can significantly increase.