On the impact of choice in multi-service P2P grids

In this paper we consider a peer-to-peer grid system which provides multiple services to its users. In this system, an incentive mechanism promotes collaboration among peers. It has been shown that the use of a reciprocation mechanism in such a system is able to prevent free riding and, at the same time, promotes the clustering of peers that have mutually profitable interactions. However, when peers are subject to a budget limitation, each peer must select a subset of all services that can possibly be offered. In this work we show that the received utility is strongly dependent of the offered services. The main contributions of this work are a methodology to evaluate the impact of service changes in the obtained utility and how much different sets of offered services impact in the peer's utility. These results indicate that further research is needed, particularly for the development of heuristics to choose the best services to offer.