Research On Routing Algorithm Based On Node Utility In Delay Tolerant Network

With the rapid enhancement of network technology and the increasing demand of social production,traditional TCP/IP protocol has been unable to meet these complex network environments.DTN(Delay Tolerant Network)emerged to address these issues.At the same time,the research on the routing protocol of DTN has become a hot topic at home and abroad.Currently,Epidemic,Spray and Wait and Prophet have become the mainstream routing protocols in DTN.However,aiming at the defects of the algorithm of Spray and Wait,this th proposes a routing algorithm SWBNU(Spray and Wait Based Node Utility).There are two improvements to SWBNU:1.Selection of relay nodes.SnW(Spray and Wait)algorithm is often blind in choosing relay nodes.To improve the issue,this thesis proposes a new concept of utility value of node.The utility value of the node is divided into the utility value of the node itself and the utility value between nodes.In this thesis,the utility value of the node is obtained by combining the two,and the node with higher utility value is selected as the relay node to complete the message forwarding.2.Distribution of message copies.When a node distributes message copies to a relay node,it determines the number of distributed message copies according to the utility value of the node itself,so as to more accurately match the number of message copies and the forwarding ability of the node.3.Improvements in the Wait phase.SWBNU defines the comprehensive utility value to comprehensively define the utility value between nodes and the utility value of the node itself,so that when the node encounters the relay node with higher utility value,the message can be forwarded for a second time.There are two innovations about SnW_Utility.1.The utility value of the node is redefined,and the residual cache of the node and the delivery probability of the message are used to determine the utility value of the node.2.Use the ACK message deletion mechanism to delete the messages that have reached the destination node,so as to save the cache space of the node,improve the delivery rate of the node and reduce the network overhead.Finally,this thesis uses a network simulation software ONE(the Opportunistic Network Environment simulator)to complete simulation experiment.Through ONE simulation platform,SWBNU algorithm and SnW_Utility are implemented in this thesis.In the simulation of SWBNU,two sets of experiments were set up to compare and analyze with Epidemic,SnW and Prophet,so as to verify the superiority of SWBNU in delivery rate,delivery delay and network overhead.In the simulation of SnW_Utility,by comparing and analyzing the performance indexes of SnW_Utility and SnW,it is not difficult to see that SnW_Utility significantly improves the success rate of network message forwarding and reduces network overhead.However,because SnW_Utility adds a node selection process when forwarding messages,the average transmission delay can be high.