Networking Technology Research Of Wlan Based On Software-Defined Network

With the continuous development of intelligent terminals, the demands for wireless resources are significantly increasing. Operators are also actively deploying WLAN network. At the beginning distributed architecture was presented. Fat APs were the first generation of WLAN products. With the increasing number of the users, the inconvenience management shortcomings were extremely highlighted. Then the centralized architecture was proposed, with the access controllers (AC) adding. Yet there are still some issues in the conventional WLAN, such as the lack of centralized management of the access points in the distributed architecture, the over pressure on the access controllers in the centralized architecture. Also, the utilities of the network equipments are limited by the venders, so as the network scalability.In this paper, with the study of traditional WLAN architecture’s disadvantages, a solution of WLAN based on Software-Defined Network to solve these problems is proposed. In SDN, network control is decoupled from forwarding and is directly programmable, which could be extended easily only by a couple of lines code. The only work the SDN switch needs to deal with is forwarding the data packages following the instructions from the SDN controllers.As WLAN is deployed by operators, within coverage of APs any user can connect to the APs, so the access authentication is necessary. By accomplishing the access authentication on SDN controller, it verifies the feasibility of the WLAN networking solution based on SDN. Before user access the internet, the SDN controller can get user information, which can be used to accomplish the access authentication by the RADIUS client module on the SDN controller. An experimental environment is built for verifying the access authentication. In addition, the multi-access authentication servers are accomplished. According to the classification base on user information, the access request will be transmit to the corresponding access authentication server. With multi-access authentication servers supporting, the access authentication efficiency can be optimized. While using queuing theory, it analyzes the improvement of access authentication efficiency by using multi-access authentication servers. In the end it gives the summary and the direction of future research.