Research On Routing And Buffer Management For DTN Based On Probability And Significance

DTN has become one of hot spots in wireless network recently, which has a wide range of applications. In DTN network, the topology changes constantly, network connections are disrupted intermittently, and there is not a end-to-end path during the transmission of messages, which is different from the basic assumption of the traditional network. Therefore, researchers designed "store- carry- forward" method for message transmission in DTN network.In DTN network, How to deliver messages to the destination efficiently, and how to deal with the competition of the limited buffer resources, are the core contents of DTNresearch. This thesis proposes a DTN routing protocol based on the probability and importance, and a buffer management method on the routing protocol. the main work of this thesis are as follows:1)This thesis introduces the architecture, the characteristics, and the applications of DTN. and summarizes the present situation of DTN routing and buffer management.2)This thesis proposes a DTN routing protocol(PROSIG) based on the probability and the importance of messages. This protocol designs a method which is used to estimate the number of message copies, and a measure function which is used to compute the importance of messages. Then this thesis defines the forwarding priority function for message, which is used to sort messages during the routing.3)This thesis designs a delete priority function for PROSIG. The function decide the message which is discarded firstly when buffer overflow. It ensure that the buffer resource ia allocated to messages which are successfully delivered with the best chance.4)The simulation results show that, PROSIG and the buffer management strategy about it can improve message delivery ratio, and reduce network overhead, which is significant for DTN network.