To solve the congestion problem at node in delay tolerant networks, an active congestion control strategy based on historical probability was proposed. The strategy put forward the concept of referenced probability that could be adjusted dynamically by the degree of congestion. Referenced probability would control the forwarding conditions to avoid and control the congestion at node. At the same time the utilization of idle resources and the transmission efficiency of the network would be promoted. The simulation results show that the strategy upgrades delivery ratio of the entire network and reduces the load ratio and message loss rate. As a result, the active congestion control is realized and the transmission performance of the network is enhanced.

Considering the problem of limited energy in Delay/Disruption Tolerant Network (DTN), a node energy-aware probabilistic routing algorithm was proposed. Nodes in network were distinguished according to energy situation, and different message delivery mechanism and energy-efficient buffer management strategy were adopted in order to achieve the balance between delivery ratio and energy consumption. Simulations indicate that the algorithm improves delivery ratio and reduces overhead ratio on low energy consumption, and has better performance on network lifetime compared with other algorithms.