SDN-Enabling The WLAN

Mobile device proliferation has made the wireless LAN today's primary mode of enterprise network access, but managing wired and wireless networks as one cohesive system remains a challenge. Extending software-defined networking (SDN) across the WLAN will help ensure consistently high performance of critical business applications and simplify unified management.

However, doing so effectively requires that wireless products offer immediate benefits to IT without additional staff training and/or the "rip and replace" of existing controllers and access points. It also requires that these products truly embrace the open architecture approach to SDN enabled by OpenFlow and advocated by communities such as the Open Networking Foundation and Project Open Daylight.

The popularity of BYOD, the ever-growing number of mobile devices, and the increased use of applications such as telepresence, Skype, and Microsoft Lync challenge the ability of IT networks to deliver consistently high-quality user experiences across unified wired and wireless access networks. With so much traffic from so many sources going to so many different devices, just understanding the traffic is difficult. Consistently ensuring performance for the most critical applications is even more so. SDN-enabling the WLAN helps to address this.

Application vendors such as Microsoft provide SDN APIs, giving WLAN vendors information to provide better tools for network monitoring, issue diagnosis, and application-specific quality of service (QoS). By OpenFlow enabling WLAN controllers and integrating similar capabilities, WLAN vendors can help IT enforce QoS for these applications.

One example of an application that would benefit from unified SDN implementation is the communication between the operating staff and floor nurses at a hospital via "nurse call." Because nurses are mobile and the nursing station is static, audio and video communication results in heavily shifting wired and wireless traffic loads, sometimes degrading the quality of the voice and video transmitted. From its central vantage point on the network, through utilization of application- and network-generated northbound and southbound APIs, an SDN-enabled WLAN controller can optimize QoS at both ends, creating a higher-quality experience for both the fixed and mobile nursing staff.

Enabling security across wired and wireless assets is another instance in which a WLAN-centric SDN implementation can add value. The influx of mobile devices has expanded the need for intrusion protection for enterprise access networks. Because attacks may come from the wireless domain or the wired LAN, SDN-enabling the WLAN controller creates a more broadly applicable firewall and intrusion protection system.

SDN-enabling QoS and security through the WLAN controller provides multiple benefits, centralizing network visibility and control, simplifying management, reducing costs, and saving time. Implementing this should be easy for IT, with minimal changes and retraining, requiring only software upgrades to WLAN controllers and navigation of a few new user interfaces. The best of these systems will draw from IT's knowledge base, keeping costs low and streamlining deployment and ongoing management.

Mobile device use has grown, but unification of management for wired and wireless networks has not kept pace with user needs. SDN will bridge this gap, enabling full visibility from the LAN switch, through the WLAN controller to the access points themselves. To truly add value to IT and end users, WLAN vendors must provide northbound and southbound APIs that are not vendor specific. This will give IT organizations the ability to integrate third-party or even homegrown management applications that meet their specific needs.

An effective, integrated, wireless SDN solution will allow IT to have:

SDN enables application performance, ease of management, and simplicity of use for the unified wired and wireless access network. However, the true extent of this openness will be determined by each vendor's implementation. Will vendors work toward truly open networks where best in class wins, or will they implement SDN from their own proprietary points of view? The degree to which these new systems are able to remove complexity from access network deployment and management -- without requiring additional training and equipment replacement -- will ultimately determine their true value.