Research On The Protocol Technology In Delay Tolerant Network Based On Service Priority Strategy

Delay tolerant network is applicable to restricted network environments with intermittent connections and high latency,of which the typical application scenarios include interplanetary Internet,mobile vehicle network and military self-organizing network,etc.Compared to TCP/IP in the traditional Internet,the protocol of DTN adds Bundle layer,so as to possess the function of store-carry-forward,which is fit for restricted network environments without continuous and stable end-to-end connections.The applications of DTN are unable to deliver all packets correctly because of intermittent connections and limited network resources.However,the importance of packets varies in many cases,so it is of great significance to ensure high delivery ratio of high priority packets in the practical applications of DTN.Combining the requirements of the scientific research project,this dissertation researches on the protocol technology in DTN based on service priority strategies.The main work includes:1)This dissertation analyzes the characteristics of DTN and the principles of Bundle protocol,and constructs the network model and specific protocol models for the rural transportation information network,i.e.an application of DTN,under ns-3 simulation software,which provides the theoretical foundation and research platform for the research on the protocol technology in DTN based on service priority strategies.2)This dissertation analyzes the impacts of typical factors such as node number,covering radius,area size,node movement model and so forth on the network performance,providing train of thoughts and performance references for the research on the protocol technology in DTN based on service priority strategies.3)This dissertation proposes two service priority strategies for the service priority requirements of DTN,i.e.Order-based Service Priority Strategy(OSPS)and Lifetime-based Service Priority Strategy(LSPS)respectively.Both strategies rely on the self-defined priority field in the Bundle header to distinguish the priorities of packets.The core idea of OSPS is to send high priority packets first,and LSPS configures high priority packets with a longer lifetime.Under the simulation conditions of this dissertation,the simulation results based on different quantity ratios of high-low priority packets show that,compared to the delivery ratio of non-OSPS,the delivery ratio of high priority packets in OSPS increases by 14.74% at most.Compared to the delivery ratio of non-LSPS,the delivery ratio of high priority packets in LSPS increases by 21.02% at most.