The Study Of Routing Protocol Switching Mechanism Under SD-WSN Architecture

Limited by volume and cost,sensor nodes in the wireless sensor network are commonly made with weaker processing capacity of CPU,less memory,lower battery capacity and other finite hardware resources,as well as one simple routing protocol for communication.To choose a suitable routing protocol,WSN designer should consider both the WSN application scenario and network requirements.although many routing protocols has been proposed,there is no general universal routing protocol,which can meet different application requirements from energy consumption,robustness,real-time performance and other aspects.What's more,routing protocols that have been deployed within the WSN nodes are difficult to be switched and deployed again.Therefore,as the WSN application requirements change,the deployed WSN routing protocol is no longer suitable.To solve the problem raised above,the programmable WSN has been proposed.Although the study provides programmable and secondary development capabilities for WSN nodes,it is not efficient enough as developers need to know all the details about how it's realized.With the development of SDN,many studies bring SDN design philosophy to WSN,and propose SD-WSN architecture.This new architecture inherits the core design characteristic of SDN,which extracts control logic from the sensor nodes to the controller.Through the controller users can obtain the whole view of network and configure it.As we can see,utilizing the controller to configure and switch the routing protocol for all WSN nodes,this new proposed SD-WSN architecture may help to solve the problem that deployed routing protocol cannot adapt to the application requirements in WSN.With the theoretical feasibility and technical support given by the design of SD-WSN architecture,in this paper we conduct researches for the routing protocol switching mechanism under this architecture.After many experiments and analyses,we selected the open source SDN-WISE solution as the basis of research,among all the related work about SD-WSN.As the SDN-WISE solution does not support the routing protocol switching,so in this paper we extend the original solution from the data layer,the control layer and the application layer respectively and finally make the switching mechanism work.With the controller in the control layer in this improved SDN-WISE solution,the dynamic switching of routing protocol is supported even when system is running.In addition,in this paper we make node models for both sensor nodes and sink nodes in WSNs based on Cooja emulation platform on Instant-Contiki operating system,and setup the emulated WSN environment.After that,we utilize SDN-WISE controller to configure and switch the routing protocol for all nodes in the emulated network.Finally we take several experiments to evaluate the proposed routing switching mechanism from aspects like energy consumption of nodes and delay of control flows.Results from experiments show that the routing switch mechanism proposed in this paper supports the run-time switching of the network routing protocol within an acceptable cost.