Research On Load-Balancing Routing Strategy Under The Software Defined Network Architecture

With the high-speed development of Internet, the performance of the traditional network architecture is facing severe test. All kinds of network services emerge in endlessly, Internet users are also increasing day by day. Due to closed and not easy to centralized management, the traditional network is difficult to implement traffic optimization strategy, and network equipments are difficult to deal with the explosion of data flow, so the current network in dire need of a new architecture to solve the problems faced. Software Defined Network(SDN) advocated the idea of control and forwarding separation is easy for managers to centrally control the underlying devices, and unified implement the routing strategy; Furthermore, the characteristic that open interface can be programming are also useful to the function of the existing network expansion, all of software development in order to realize the strategy greatly reducing the expense and difficulty. Among them, OpenFlow technology as one realization of the SDN, and its multi tuples flow-matching method can achieve a more granular traffic optimization. This paper will be based on the Software Defined Network architecture, using OpenFlow technology to solve the problems of traffic optimization.In this paper, the scenario is the park level network(such as campus network) that there are many paths between the user node and the service's node. Firstly, the network architecture is reconstructed based on the software defined network, and then, designed each layer of the architecture in detail. Design of the controller is the core of the architecture, several core function module including the discovery of link, link traffic monitoring and management network topology, computing routing and generating strategy.The main idea of this strategy is that, using the ability of openflow-controller's centrally control to monitor the links, and calculate the link's cost value as weight, under the premise of satisfying the link load balancing, combined with the Dijkstra algorithm to calculate the paths.When a new data request, the controller will sends the flow tables to the corresponding switches based on the results of pathsFor the specific implementation of the architecture, especially the realization of the control level, the various functional modules have been developed based on the Floodlight controller. The modules include Link Discovery, Link Monitoring, Topology Management, Routing Calculation, Send Strategy and so on. Finally, this paper designed related experiments based on Mininet or hardware devices, and the results of experiments show that the proposed link load balancing routing strategy can significantly improve the link utilization and the quality of service.