Optimization of an eMule-like modifier strategy

One of the main issues in peer-to-peer file-sharing services is to ensure balanced transfers of data among peers. For instance, the popular eMule file-sharing client interface implements techniques based on a credit system and time modifiers, in order to guarantee a fair degree of contribution/reward, e.g., to prevent leeching. However, fixed heuristic modifiers may not be able to guarantee a fair treatment for every peer participating in the service. This paper introduces an optimized strategy to compute modifiers in order to promote cooperation among peers, while guaranteeing a suitable degree of fairness. Simulations are provided to compare the proposed mechanism to the standard one adopted by the popular eMule client interface.