A routing policy based on time-varying graph for predictable delay tolerant networks

The problem of choosing the best forwards in Delay Tolerant Networks (DTNs) is crucial for minimizing the delay in traffic delivery. Different from the traditional networks, end-to-end delay in DTNs includes the propagation delay, transmission delay and also the waiting time introduced by the intermittent connectivity of links. In this paper, we widely discuss and mathematically formalize the computation of end-to-end delay. It is shown that the DTN end-to-end delay is determined by the starting time at source node, the traffic volume as well as the variation of edge parameters within a given time horizon. A novel routing strategy is proposed that the cumulative traffic of one link is used to calculate the transmission delay and the waiting time for crossing multiple connectivity intervals of that link. Several simulation results are also presented to evaluate the proposed routing mechanism in a satellite DTN scenario driven by real mobility traces.