A Two-Side Perspective on Cooperation in Mobile Ad Hoc Networks ⋆

Abstract. Technological advances are leveraging the widespread deployment of mobile ad hoc networks. An interesting characteristic of ad hoc networks is their self-organisation and their dependence of the behaviour of individual nodes. Until recently, most research on ad hoc networks has assumed that all nodes were cooperative. This assumption is no longer valid in open (spontaneous) networks formed by individuals with diverse goals and interests. In such environment, the presence of selfish nodes may degrade significantly the performance of the ad hoc network. In open mobile networks, users may become selfish to defend their devices from the unfair load distribution presented by many protocols, designed to optimise other criteria, such as the number of hops in the message path. This paper summarises research results addressing the problem of unfairness in open mobile ad hoc networks from a two-side perspective: the detection and punishment of selfish users and the definition of a more fair network environment that attempts to leverage the load among the participants to prevent selfish behaviour.