Research And Design Of WLAN Based On SDN

With the rapid development of mobile Internet industry, the number of mobile users soared, and WiFi access is the preferred way of wireless users to access to the Internet. As the amount of data is increasing, the business needs change rapidly, the function of wireless access point is getting more and more complex, whose structure is becoming more and more bloated. At the same time, the manufacturer’s standard is different, so that the network equipments can not be mix used, that network deployment and upgrade costs are high. Software defined network(SDN), with its characteristics of control and forwarding plane separation, centralized control, providing the open application programmable interface, has become a research hotspot of the new network architecture. Noticing tha there has been a lot of research in wired network at present, but the research in wireless access network is still relatively rare. Due to the complexity of the wireless network and the mobility of the hosts, introducing SDN into the wireless network to solve the problem that the traditional network architecture can not solve, is also a research hotspot of the scholars.Are reviewed in this paper, several modes of current WLAN network structures’ advantages and disadvantages are analyzed, especially the performance impact brought about by centralized function of equipment control and forwarding, and which can not provide open interface to satisfy the operation of the network rapid escalation and deployment. On this basis, the software defined network is introduced, the feasibility of applying SDN to wireless network field is analyzed, as the advantages of the control and forwarding split are brought forward. And it expounds the current researches in the field of wireless networks based on SDN development, to provide the basis for introducing SDN into WLAN.The paper brings forward a mechanism of split WLAN, that the wireless access control, data forwarding path control, QoS and network security control function are integrated in the controller, and equipment parameter configuration and management functions of the APs and switches are also implemented in the controller. The controller manage all APs in the region centralized, the AP itself just do the frame forwarding work. Through the architecture, the wireless terminal can easily roam between APs, and the overall behavior of the network can be easily carried out by the controller, to optimize the network by load balancing and so on. In addition, because the controller provides the programmable interface, it can be easy to deploy a new network strategy, and there’s no need to make changes to the underlying facilities. On this basis, the paper puts forward the design of wireless access module on Floodlight controller, and demonstrates the feasibility of the architecture and the specific implementation methods.The paper puts forward a load balancing method in WLAN network architecture based on software defined network combined with with the same frequency deployment. With the characteristics of centralized control, low consumption of precise measurement, and the seamless switching in the architecture, by using the unified controller to control the data forwarding path on each AP and dynamicly adjustment the connection between each access point and mobile terminal users, to achieve the purpose of network load balancing.Pointing out the advantage of the architecture introduced in this paper.