For those who worry about things like which channel large groups of wireless access points are on, there hasn't been a lot to get excited about during the last couple of years. For most "smart WLAN systems," you put your faith in a murky channel selection algorithm, respect that the 2.4-GHz band has only three non-overlapping channels, and hope that the vendor built the right intelligence into the product set. That changes with ChannelFly, the new channel selection method from Ruckus that challenges tradition and promises big payoff for those willing to try the new magic.
Everyone in the wireless game knows that channels 1, 6 and 11 are safely spaced in the 2.4-Ghz band used by 802.11g and 11n, leaving each other alone from the perspective of adjacent-channel interference. This has been a fundamental tenant in designing networks from the days of manually configured stand-alone access points through today’s new sophisticated auto-channel systems that use various techniques to pick which frequencies APs in a given area should be on.
On occasion, a daring admin will go off the reservation and use channels 1,4, 8 and 11 and swear that all is well with this combination, while those of us drawing spectral masks in our heads question the wisdom of playing with fire where channel edges are made to intentionally overlap by a smidgen. Then there’s the curious Meru single-channel architecture that is beyond explanation here. But for most of us, faithful adherence to the 1, 6 and 11 rule has been our motto and credo, and we’ve made it work in even the busiest environments. Or have we?
Until Ruckus’ ChannelFly feature set, controller-based WLANs have relied primarily on periodic off-channel scanning and simple noise and traffic instant-in-time measurements to see if there might be a better channel available in the range that the system is set up to use. The 1-6-11 mentality has permeated the market to the point where even top-tier vendors assume that it is the basic framework their deterministic RF management tools will use as they change in reaction to RF environmental conditions. ChannelFly challenges the conventional wisdom with a new bag of tricks and use of all channels that promises improved wireless capacity (on the order of 25% to 100%) in congested environments.
Using what Ruckus describes as "a statistical adaptive channel selection technique," ChannelFly says that an access point simply can’t make the best channel selection decision based only on what it hears and senses. True, and constant channel capacity testing is the secret ingredient in ChannelFly. Though I have yet to fully understand the mechanics of it, I am impressed that Ruckus thinks so much of ChannelFly that it is inviting users to allow all channels (not just 1, 6 and 11) to be selectable, thus making it a new day in this area. (I’ve dwelled on the 2.4-GHz band here, but ChannelFly also works in the more channel-rich 5-GHz spectruml.)
As I am not a Ruckus customer, I cannot comment on whether ChannelFly lives up to its billing as the next step in the evolution of the company’s patented BeamFlex antenna technology. But I do know that wireless environments are being bombarded by scads of new portable Wi-Fi-capable devices that support only the 2.4-GHz band, thus making an already hostile spectrum even more contentious. If ChannelFly can really make things better in this increasingly performance-challenged territory, then existing Ruckus customers will greatly appreciate the free upgrade to supported access points, while those in the market for a WLAN solution will have something truly new to hear about for RF management.
At the time of publication, Ruckus has no business relationship with Lee Badman.Lee is a Wireless Network Architect for a large private university. He has also tought classes on networking, wireless network administration, and wireless security. Lee's technical background includes 10 years in the US Air Force as an Electronic Warfare systems technician ... View Full Bio