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Cisco Raises The Stakes For Mission-Critical WLAN

Cisco Systems has rolled out its new CleanAir technology with an aim to thwart one of the biggest challenges to the enterprise WLAN, RF interference. Using CleanAir, the Cisco wireless network monitors the air quality within the environment, identifies sources of interference, and if necessary, moves affected access points to cleaner channels. This new level of airspace intelligence and proactive optimization is raising the bar for wireless networks and bringing the dream of self-healing, mission critical WiFi to the market.

Cisco's CleanAir technology has its roots in the Cognio spectrum analyzer tools, acquired by Cisco in late 2007.  Cognio's solution paid particular focus on not only visualizing what is going on in the airspace, but identifying the sources of interference, based on RF signatures.  But like nearly all of the spectrum analysis tools, the laptop-based application offered a reactive approach. The administrator had to physically go to the trouble spots in the building and hope to catch the interference while it was happening. After over two years of development work, Cisco has finally moved these spectrum analysis tools into the wireless infrastructure itself.

At the heart of the CleanAir system are the new Aironet 3500 series access points. The new APs feature a custom CleanAir ASIC that continually scans both the 2.4 and 5Ghz wireless spectrum for any signs of interference without requiring dedicated use of one of the access point's radios. Cisco notes that the new access points can detect and classify more than 20 different types of wireless interferences, distinguishing, for example, a cordless phone from a microwave oven or Bluetooth radio. 

Air quality data and location information of the interference is collected from all CleanAir equipped access points in the network, merged and collated within Cisco's Mobility Services Engine (MSE) appliance to build an Air Quality Index value for every part of the wireless network.  If this air quality value dips below a certain threshold, CleanAir takes corrective action, instructing the wireless controller's radio resource management to move affected access points to a new channel and at least temporarily marking the noisy channel as unusable. 

Administrators can also access this air quality data from Cisco's Wireless Control System (WCS) to not only get a real-time view of the air quality of their wireless infrastructure and use the location information to remove sources of interference, but also access the forensic history stored on the MSE to go back in time and identify trouble. This element is particularly useful to catching and identifying a moving target, such as a cordless phone, and with this level of history, an administrator can actually follow an interfering device as it moves through the building.

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