On incentivizing caching for P2P-VoD systems

Peer-to-peer (P2P) systems consist of selfish peers which would like to receive services from others but would not like to contribute their own resources by default. To conquer this problem, proper incentive schemes are needed so as to stimulate the peers' contributions. This issue is particularly important for P2P Video-on-Demand (VoD) services. Content providers of P2P-VoD services want to incentivize peers to cache video data so that the peers can transfer data to one another and alleviate the workload of the content server. In this paper, we design a practical mechanism under which the peers are rewarded based on the popularity of the video they cache. We characterize the impact of this incentive scheme on peers' caching behaviors. In particular, we formulate an optimization framework to decide the optimal reward price for each video so as to keep enough replicas and minimize the content provider's operational cost. Via extensive simulations, we validate the effectiveness and efficiency of our incentive scheme.