A Faithful Distributed Mechanism for Sharing the Cost of Multicast Transmissions

The problem of sharing the cost of multicast transmissions was studied in the past, and two mechanisms, marginal cost (MC) and Shapley value (SH), were proposed to solve it. Although both of them are strategy proof mechanisms, the distributed protocols implementing them are susceptible to manipulation by autonomous nodes. We propose a distributed Shapley value mechanism in which the participating nodes do not have incentives to deviate from the mechanism specifications. We show that the proposed mechanism is a faithful implementation of the Shapley value mechanism. We experimentally investigate the performance of the existing and the proposed cost-sharing mechanisms by implementing and deploying them on PlanetLab. We compare the execution time of MC and SH mechanisms for the tamper-proof and autonomous node models. We also study the convergence and scalability of the mechanisms by varying the number of nodes and the number of users per node. We show that the MC mechanisms generate a smaller revenue compared to the SH mechanisms, and thus, they are not attractive to the content provider. We also show that increasing the number of users per node is beneficial for the systems implementing the SH mechanisms from both computational and economic perspectives.