Stability and delay analysis of delay tolerant networks with random message arrivals

We study stability and average delay in single-source single-destination delay tolerant networks with random message arrivals. In particular, we analyze source spray-and-wait routing protocol without feedback. We obtain conditions on arrival rate under which the source queue is stable. We show that the maximum supported arrival rate is linearly proportional to the number of relays and inversely proportional to the spray-and-wait parameter. Further, we obtain an approximate expression for the average queueing delay. We show that it increases with the spray-and-wait parameter. Through simulations, we show that the average delivery delay and average end-to-end delay first decreases and then increases with the spray-and-wait parameter. We also validate our analytical findings through simulations.