| In recent years, Delay Tolerant Network (DTN) has been widely concerned, the areas which DTN applies are mainly concentrated in the deep space network, satellite network, land mobile network and so on.Due to the difference between the traditional network and DTN in high delay, long intermittent connectivity and limited resources, At present, the research field of DTN mainly concentrates in the network model, topology control, routing and congestion control.Because of its special message transmission, in the routing protocol, DTN generally adopts the multi copy routing protocol based on the replication strategy. With the message copies increasing, the routing protocol not only improves the delivery rate, but also decreases transmission delay. However,it will makes the node buffer occupancy rate,cause a lot of redundancy to the network, impact the network performance.Based on the Spray and Wait routing protocol, According to its blindness in the message spray stage, this thesis puts forward the node properties Model, takes the movement and relation attributes into spray and wait routing protocol, then it proposes a new routing protocol named BNP-SW. Experimental studies shows that compared to traditional routing protocols the improved algorithm named BNP-SW can greatly improve the message delivery rate and reduce transmission delay.Since the routing protocols based on multiple copies are likely to cause network congestion, when the node in the network discards messages, it also used the remaining time of the message as the choice standard. Based on the Traditional Drop oldest Congestion Control Strategy, this thesis puts forward the message properties Model, which combined the number of copies of the message with the remaining time of the message. We propose a new Congestion Control Strategy named Drop BMP. Experimental studies have shown that this Congestion Strategy can effectively decrease the network overhead and improve the message delivery rate. |
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