Research On Routing Strategy For Software-Defined Networking

Software Defined Networking(SDN)is one of the most promising network architectures available today.Its design philosophy is ”separation of forwarding and control” to manage the network more easily than traditional networks.One of the core SDN technologies is Network Function Virtualization(NFV).SDN can create virtual machines based on NFV and load virtualization functions to achieve unified management and dynamic configuration of network resources so as to fully realize network programmability,scalability and security.In traditional networks and SDNs,routing is one of the most important tasks.The former uses some distributed routing algorithms,but these algorithms can not perceive the global network topology and make optimal routing decisions.In contrast,SDN can sense the global network topology,but how to forward traffic in a complex network environment is also very difficult problem.In order to effectively improve data forwarding performance,many researchers are devoted to studying the routing mechanism in SDN.The advantages and disadvantages of the routing strategy can directly determine the distance,delay and number of hops of the packet.As a result,the bandwidth utilization is low and the load is unbalanced.The work of this paper is mainly reflected in the following two aspects:Firstly,a routing model of active and standby paths is established,an efficient routing algorithm of active and standby paths is proposed,and the active and standby paths of high quality are effectively selected.In the first phase of the algorithm,single-path routing algorithm is realized by using ”Node-Scaling” operation to reduce the complexity of the single route,and then using the improved LKH algorithm to find a valid single path.In the second phase of the algorithm,based on the single-path routing algorithm,two types of ”path punishment rules” are introduced to implement the active-standby path routing algorithm.The experimental results show that compared with the other three algorithms,the proposed routing algorithm shows better performance in terms of ”the number of duplicate edges of the primary and backup paths” and ”the total cost of the primary and backup paths”.Secondly,this paper considers multipath routing problem as a link separation problem with a bandwidth of ? Max-Min,and proposes an efficient multi-path routing algorithm.In the first phase of the algorithm,Dijkstra's algorithm was used to find a set of candidate paths from the source node to the destination node in polynomial time.In the second phase of the algorithm,a greedy algorithm is used to select a path with ? link separation from the candidate path with a high bottleneck bandwidth.The simulation results show that the proposed algorithm is obviously superior to the other two kinds of algorithms in improving the throughput of MPTCP stream and the throughput difference between paths.Finally,on the basis of summarizing the research work,the paper points out the areas to be improved and prospects the follow-up research directions based on SDN routing problem.