Managing Reputation over MANETs

The use of small portables and mobile devices has made MANETs (mobile ad hoc networks) very popular. A MANET is a network composed by a group of mobile nodes without any fixed device or a central coordination. They work in an open net and their collaboration is the sole means to allow communications and the survival of the MANET itself. A critical issue is to assess the behaviour of the nodes that participate in the network, possibly identifying selfish conduct that can compromise the functioning of the system. This paper shows a method to evaluate the behaviour of all nodes by establishing a reputation value that represents the trustworthiness of each node. A protocol is presented to calculate the reputation of a node by locally observing the node from another one, and then tuning this intermediate value with additional observations from other participants. When the reputation value of a node is available, it is circulated and distributed uniformly over the network. This reputation protocol is viable. Each node can efficiently calculate the reputation values of its neighbours and then of all network nodes. A variety of simulations conducted using the network simulator NS-2 strongly support these claims.