A performance study of incentive schemes in peer-to-peer file-sharing systems

Incentive schemes are designed to promote cooperation in distributed systems, in which peers are free to decide how much to contribute. A variety of incentive schemes have been proposed in peer-to-peer file-sharing systems, touted to have special advantages in certain scenarios. However, only little research has been done on comparing these incentive schemes under an identical scenario. Fairness is an important indicator to evaluate an incentive scheme, because good fairness can enable proper rewarding to collaborative peers and punishment to strategic peers. In this paper, the correlation map between return and investment of peers is used to depict the fairness degree of different incentive schemes. The fairness and efficiency of several representative incentive schemes are compared under rate-based metrics (all chunks have an identical value) and value-based metrics (different chunks have different values).