Research On Routing Technology Of Software Defined Network

With the rapid development of the Internet,the demand for quality of service is getting higher and higher.However,the current IP network uses distributed routing control mechanism,and it is difficult to realize the dynamic allocation of network resources.As the new network architecture,the Software Defined Networking(SDN)separates network control from data forwarding.The centralized routing control mechanism in SDN network can easily select the QoS-constrained path for service flow.Therefore,researching on the routing technology in SDN network is significant both in theoretical perspective and in application value.By analyzing the characteristics of SDN network structure and the characteristics of OpenFlow protocol,this thesis compares the essential difference between IP network routing technology and SDN network routing technology,summarizes the advantage of SDN network to realize QoS routing technology and designs the QoS routing scheme based on SDN network.In order to solve the issue of IP network link information inaccuracy,this thesis uses OpenFlow protocol to collect information of network flows in real time in an active way.In addition,in order to simplify the complexity of QoS routing algorithm,this thesis designs and implements simulatedly a routing algorithm with QoS constraint based on Dijkstra algorithm,the algorithm selects a route with QoS constraints according to the whole network topology and link cost.This thesis tests the used bandwidth of the SDN network link on the floodlight controller which is a open source experiment platform.The test results show that the exact state of bandwidth usage of the links can be captured;The effectiveness of the routing algorithm with QoS constraints in SDN network is tested,and the experimental results show that the QoS routing algorithm can effectively provide a QoS constrained routing for the service flow according to the service flow type.