08 February 2010

The Lessons Of Wi-Fi #1: Not All Wi-Fi Networks Are Created Equal

You've invested thousands - tens of thousands - in new educational software, a fleet of new Wi-Fi enabled laptops, and even computer carts to chauffeur computers between classrooms. But when the students fire up the machines and try to access the shiny new instructional video you're trying to stream wirelessly, they get nothing. Nothing but static. Or jitter. Or dropouts. What went wrong?

Those who forget the lessons of Wi-Fi are doomed to repeat them. Lesson #1: not all Wi-Fi networks are created equal. They all have access points, and they may even be Wi-Fi Alliance certified. But the similarity ends there.

Streaming real-time video is a demanding Wi-Fi application that requires additional processing above and beyond the Wi-Fi standard.
The main technology enablers for video over Wi-Fi are adequate bandwidth, quality of service (QoS), and multicast support.

While 802.11n - the newest high-speed Wi-Fi technology - provides a significant bandwidth boost,
RF management algorithms are important to ensure continuous, high-rate coverage. These algorithms must include control of the access points and the laptops (clients) - a feature provided by Aruba's Adaptive Radio Management technology - to automatically calculate the optimum channel and transmit power assignments, move clients to the most appropriate access point, and optimize the network’s use of available radio spectrum. This function is especially important for mobile clients - like iPhones - and in the presence of densely deployed clients such as you would find in classrooms and lecture halls.

QoS for video uses the same mechanisms as for voice, however, the bandwidth requirements of video applications vary widely. It is therefore important that any content that requires special handling be correctly flagged. Aruba's integrated stateful firewall does just that.

Since video can account for a large percentage of network bandwidth, determining when to broadcast to multiple clients - multicast streaming - is essential. Here again, Aruba incorporates technology to monitor multicast group members, and only delivers multicast streams to access points whose clients require it.

If you'd like to get the whole picture on video over Wi-Fi you've only to download our free white paper,
I Can See Clearly Now. And leave it to someone else to relearn the lessons of Wi-Fi.