Programming the Enterprise WLAN: An SDN Approach
Lalith Suresh Puthalath · 2012
Enterprise WLANs need to support a wide spectrum of services and functionalities. This includes authentication, authorisation and accounting, policy management, dynamic channel reconfigurations, mobility and interference management, and load balancing. Vendor solutions that address these problems are proprietary, and closed source, leading to vendor lockin. They restrict flexibility for the network operator. This thesis explores the introduction of programmability into the enterprise WLAN, demonstrated through a prototype system named Odin, with the goal of empowering the network operator, and to make enterprise WLANs extensible. Through Odin, we provide a set of abstractions and interfaces using which different enterprise WLAN services can be implemented as network applications. Odin is based on a software defined networking (SDN) approach, wherein the WLAN is orchestrated through centralised control, as dictated by a set of network applications. Odin’s SDN framework also takes into account the unique challenges of WLANs. For instance, clients in the IEEE 802.11 protocol make access point association choices entirely on the basis of local decisions. To this end, Odin builds on a light virtual access point abstraction that takes control of the client’s association decisions, and greatly simplifies client management. Additionally, Odin’s architecture does not expect any hardware or software modifications on the 802.11 client, and its design supports WPA2 Enterprise. Experimental evaluations conducted within an enterprise WLAN setting demonstrate Odin’s feasibility.