Optimal server scheduling in hybrid P2P networks

We consider the server scheduling problem in hybrid P2P networks in the context of a fluid model. Specifically, we examine how to allocate the limited amount of server upload capacity among competing swarms over time in order to optimize the download performance experienced by users. For sufficiently high user churn rate, we prove that it is optimal to allocate the full server capacity at all times, and that it does not matter exactly how the capacity is distributed among competing swarms as long as no upload capacity is unnecessarily left unused. While it may seem obvious that it is optimal to allocate the full server capacity, we show that this is not always the case, surprisingly enough when the user churn rate is not high. In that case, throttling the server capacity slows down downloads in the short run, but also boosts the future peer upload capacity, and may thus lead to higher download speeds in the long term.