Incentives in bittorrent induce free riding

We investigate the incentive mechanism of BitTorrent, which is a peer-to-peer le distribution system. As downloaders in BitTorrent are faced with the con ict between the eager-ness to download and the unwillingness to upload, we re-late this problem to the iterated prisoner's dilemma, which suggests guidelines to design a good incentive mechanism. Based on these guidelines, we propose a new, simple incen-tive mechanism. Our analysis and the experimental results using PlanetLab show that the original incentive mechanism of BitTorrent can induce free riding because it is not eec-tive in rewarding and punishing downloaders properly. In contrast, a new mechanism proposed by us is shown to be more robust against free riders