What you should know about SDN and Wi-Fi

This vendor-written tech primer has been edited by Network World to eliminate product promotion, but readers should note it will likely favor the submitter’s approach.

Software-Defined Networking (SDN) is coming to Wi-Fi to give IT end-to-end control of the unified (wired and wireless) network. SDN will deliver numerous additional benefits, ranging from cost saving to increased productivity. Here are three of the most important things you should know about SDN-enabled Wi-Fi:

1: Key benefits. One of the immediate advantages of SDN is it simplifies networks. Consolidating around a central control structure allows for greater automation. This makes rolling out new services faster. Another benefit of SDN is simpler provisioning over multi-vendor networks.

SDN also improves the dynamics of the network by, for example, allowing the network to adapt to load. The SDN-enabled network responds dynamically to changing policies and traffic loads and the network administrator is freed from manual, time-consuming tasks. The cost savings associated with reducing the “human middleware” is yet another potential benefit of SDN.

While organizations will discover more niche SDN applications that deliver savings, improved productivity and revenue generation opportunities, there are few key features which can only be achieved using SDN Wi-Fi. These include: 

  • Network visualization: With the invention of WLAN controllers, network engineers lost visibility across the unified (wired and wireless) network. This impedes troubleshooting, traffic optimization, capacity planning, and other critical functions. SDN Wi-Fi enables network visualization across the unified network.
  • Application SLAs across the unified network: With SDN, IT policies are defined once and then are enforced consistently across both wired and wireless networks. Users have a uniform experience, regardless of their access method.
  • Location services: Since most users access the network wirelessly, SDN-enabled Wi-Fi lets IT make dynamic decisions using the physical location of the user.

2: WLAN controller supports SDN. Early WLAN architectures based on access points and WLAN controllers were already designed to decouple the data and control planes. But as vendors implemented their own forms of WLAN controllers, they became highly proprietary and closed to extensions to address other business needs. With SDN taking center stage for wired networks, it makes an obvious choice for the WLAN controllers and access points.

A WLAN controller claiming support for SDN implies that it must support OpenFlow – allowing forwarding of client data packets within OpenFlow flows. Instead of all decisions being made by the WLAN controller, an application/SDN controller can make decisions regarding which packets go where. Such a WLAN controller supports all OpenFlow actions, including “Set IP TOS bits,” “Strip the 802.1q header,” “Set the 802.1q VLAN id,” “Set the 802.1q priority,” “enqueue port queue,” and more based on the ingress IP source address, IP destination address, IP protocol/IP ToS bits, Transport source port/ICMP Type, Transport destination port/ICMP Code, Ethernet source address/destination address, and VLAN id/VLAN priority – and the list goes on.

3: Managing unified policy. Since the forwarding plane of every OpenFlow-enabled network device can be managed by a single centralized SDN controller, IT operators can now do traffic shaping and policy control across the whole network. In these cases, the IT operators do not even need to know how that box implements SDN, or even whether the box is wired or wireless. This is achieved through the use of SDN applications that run on the SDN controller. Using OpenFlow, an application can set the QoS parameters for any flow and it does not matter if the devices are wired or wireless.

Meru Networks is a provider of intelligent 802.11ac Wi-Fi solutions, providing uninterrupted user experience for education, healthcare, hospitality and enterprise. Designed to enable seamless roaming with traffic separation for critical applications, the Meru MobileFLEX architecture delivers optimized performance and high capacity in high-density environments.

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Copyright © 2014 IDG Communications, Inc.