Software-defined networking on the edge


Software-defined networking (SDN) enabling the wireless LAN (WLAN) can help deliver a consistently high performance of critical business applications and simplify unified management of wired and wireless networks. However, to do this effectively, WLAN vendors need to provide solutions that offer immediate benefits to the IT department without any additional training or a "rip-and-replace" of existing controllers and access points.

It also means that these solutions must truly embrace the open architecture approach to SDN enabled by OpenFlow and advocated by communities and industry organizations like the Open Networking Forum and Project Open Daylight.


The rise of mobility

The rising number of mobile devices, growing popularity of bring your own device (BYOD) and increased use of applications, such as telepresence, VoIP, video conferencing and others, put added pressure on IT networks to deliver a consistently high-quality experience 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 hard enough. Consistently ensuring a fast, seamless and reliable performance for the most critical applications is even more challenging. SDN-enabling the WLAN can help address this.

Microsoft and other major application vendors provide SDN APIs, giving WLAN vendors the information they need to provide better tools for network monitoring, problem diagnosis and application-specific quality-of-service (QoS). By OpenFlow-enabling their WLAN controllers and integrating similar capabilities, WLAN vendors can help IT enforce QoS for these applications.

A "nurse call" application in a hospital -- the communication between operating staff and nurses -- is a good example of an application that would benefit from a unified SDN implementation. Since nurses are mobile and nursing stations are static, audio and video communication results in constantly shifting traffic loads between wired and wireless networks, which can degrade the quality of the voice and video being used. 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, resulting in a much better experience for nursing staff.

Securing the network

Enabling security across both wired and wireless assets is another example of how a WLAN-centric SDN implementation can add value. The influx of smartphones, tablets and other mobile devices has expanded the need for intrusion protection for enterprise access networks. Since attacks can come from the wireless domain or the wired LAN, SDN-enabling the WLAN controller creates a more comprehensive firewall and intrusion-protection solution.

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 few changes and re-training, requiring only software upgrades to existing WLAN controllers and navigation of a few new user interfaces. The best of these systems will draw from IT's existing knowledge base, keeping costs down and streamlining deployment and ongoing management.

Mobile device proliferation has made the WLAN the primary mode of enterprise network access, although unification of management for wired and wireless networks has not kept pace with users' needs. SDN will enable WLAN vendors to effectively bridge this gap.

Existing unified access management platforms are costly and closed, providing visibility and control of LAN switching, as well as WLAN controllers and access points, but typically only when you purchase the entire solution from a single vendor. Working to protect that "lock-in", some WLAN vendors who claim support for SDN are actually doing much less. Taking the information exposed by application vendors' SDN APIs and using it to their own advantage -- optimizing performance of those applications without enabling any additional management of their controllers and access points -- is an ineffective SDN implementation.

Only by enabling full visibility into and control over their networks, from the LAN switch through the WLAN controller to the access points themselves, can WLAN vendors truly deliver on the promise of SDN. They must provide north and southbound APIs that are not vendor-specific to really add value to the IT department and their end users. This gives IT organizations the ability to integrate third party or even home-grown management applications that meet their specific needs.

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

  • End-to-end application QoS enabling enforceable service-level agreements (SLAs)
  • Single-pane-of glass management of the unified wired and wireless network, with policy automation
  • The ability to mix and match solutions from different vendors

SDN can enable 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 solutions win, or will they simply 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.

Ajay Malik is the senior vice president of engineering at Meru Networks

Published under license from, a Net Communities Ltd Publication. All rights reserved.

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