Quality of Service in Large Scale Mobile Distributed Systems Based on Opportunistic Networks

Delay Tolerant Networks formed by mobile devices users carry in their everyday life are starting to be an interesting alternative for message transmissions between users. However, the reliability of the DTNs is an important research topic, one of the main causes of poor DTN reliability being the selfishness of the network nodes. In this paper, we evaluate the impact of selfishness on the efficiency of several types of DTN routing protocols and determine what are the conditions that have to be met in order to provide some level of QoS in a DTN architecture. We also investigate which is the most suitable routing protocol, given a realistic scenario in which nodes move in a non-random way and manifest a typical human movement model (home-work-home/evening activity). We also suggest two ways for the improvement of the performance of such a protocol: the use of monetary incentives and the use of social incentives.