SDWLAN: A flexible architecture of enterprise WLAN for client-unaware fast AP handoff

Currently, enterprise WLAN is facing rapid growth of user scale and traffic load, as well as constantly emerging new features. However, traditional enterprise WLAN architecture suffers from poor flexibility and the lack of coordination between wireless access points (APs) and wired backbone. Inspired by the emerging idea of Software-Defined Networking (SDN), we proposed SDWLAN, an alternative architecture for enterprise WLAN. The salient features of SDWLAN are twofold. First, most of 802.11 AP functions are decoupled from scattered devices and centralized in a controller, leaving some simplified devices (i.e., wireless access switches, or WASes) manipulated by the controller through extended OpenFlow protocol. Second, the control of APs and wired backbone are consolidated to provide a unified network control platform. By reorganizing 802.11 AP's functional modules, SDWLAN can achieve remarkable flexibility. Benefiting from the extended OpenFlow protocol and the unified control platform, we proposed a client-unaware fast AP handoff mechanism in SDWLAN. Simulation results demonstrated that AP handoff operation in SDWLAN leads to negligible throughput fluctuation of on-going connection compared to traditional architecture with 802.11 standard handoff mechanism. Furthermore, SDWLAN requires no modification to existing 802.11 clients, which make our solution practical.