Research On Key Routing Technology Of SD-MANET Based On Geographic Location Information

In recent years,the new architecture of Software Defined Mobile Ad Hoc Network(SD-MANET)centrally manages the network,realizes information processing or service customization by direct programming at the high level of the network,and is more flexible in network management and control.Therefore,SD-MAENT architecture has made new breakthroughs in the research of network load balancing,Qo S and network security prevention.However,with the increase of control functions,the control plane of SD-MANET generates more and more control overhead.Among them,the centralized routing method based on topology needs to perform protocol analysis,network resource monitoring,flow table delivery,and route maintenance,etc.The control overhead brought by it cannot be ignored,resulting in excessive occupation of limited network resources,which degrades the overall performance of the network.Therefore,in order to reduce the control overhead of SD-MANET,this thesis proposes a software-defined Greedy Perimeter Stateless Routing(SD-GPSR)method based on geographic location information.The main work of this thesis is as follows:First,a SD-GPSR routing method is proposed.In this routing method,some routing functions in SD-MANET are delegated to the data plane,and the routing is realized by using the geographical location information of nodes.The controller is mainly responsible for providing location services and partial centralized decision-making.The nodes of the data plane use the improved greedy forwarding algorithm GPSR＿DA based on distance and angle to forward data,thereby improving the self-organization ability and overall routing efficiency of nodes,and at the same time control overhead of routing is greatly reduced.Secondly,this thesis proposes a centralized solution to the problem of routing holes in GPSR greedy forwarding combined with SDN technology.In this thesis,the global location information and neighbor relationship maintained in the SDN controller are used to estimate the cost from the two aspects of path length and node stability,uses the A*algorithm to calculate an optimal routing path that avoids routing holes,and then use the source routing idea to issue the flow table to reduce the control overhead.In addition,this thesis proposes a location retention method,which carries the predicted destination node location information through the data packets returned by the destination node,and dynamically updates the destination node location information at the source node.On the one hand,the frequent location request overhead caused by the movement of the destination node is reduced,and on the other hand,the packet discarding caused by the wrong location of the destination node is also reducedFinally,this thesis uses the OPNET 18.6 simulation platform to build a simulation model,and connects the external Ryu controller through the hardware-in-the-loop simulation interface to verify and analyze the SD-GPSR routing method proposed in this paper.The simulation results show that SD-GPSR significantly reduces the control overhead of the routing layer,and at the same time significantly improves the network end-to-end delay and packet loss rate.Compared with centralized SD-MANET routing,the control overhead and packet loss rate are reduced by 51.97% and 44.69%,respectively,and the end-to-end delay is increased by 0.0831 seconds;compared with GPSR,the packet loss rate is relatively reduced by 22.56%,and the delay is increased by0.017 seconds;compared with AODV,the packet loss rate is relatively reduced by30.33%,and the delay is reduced by 0.1074 seconds.