Fast file dissemination in peer-to-peer networks with upstream bandwidth constraint

How to minimize the time of disseminating a large file from a single source to a large number of users is a fundamental question in peer-to-peer applications. Most previous works do not present a lower bound on the dissemination time, and fail to show how close the dissemination time of their algorithms are to the lower bound. In this paper, we analyze how to decrease the dissemination time by efficiently utilizing the upstream bandwidths of nodes. We first present a tight lower bound on the dissemination time that can serve as a benchmark for evaluating the performance of peer-to-peer file transfer algorithms. Then we find an equivalent condition along with a sufficient condition for fully utilizing the upstream bandwidths of nodes, in the networks where only the upstream bandwidths of nodes can constrain the transfer rates between nodes. Based on the theoretical analysis, we also design an algorithm called Receiver-schedule for fast dissemination, which can efficiently utilize the upstream bandwidths of nodes by dynamically adjusting the chunk distribution among nodes. Our simulation results show that, by using the algorithm the dissemination time is more than the lower bound by at most four percent in many cases in the networks with the upstream bandwidth constraint.