AirFlow simplifies WLAN deployment

AirFlow Networks last week launched wireless LAN switching products that are intended to simplify corporate WLAN deployments.

Using the AirFlow switch and its companion AirHubs, network executives can create a WLAN infrastructure without complex site surveys, radio signal measurements and channel assignment plans. The idea is to eliminate one of the biggest ongoing headaches not just in deploying but also changing WLANs with scores or hundreds of conventional access points.

"In a typical WLAN deployment, you have multiple access points, and you have to map coverage and worry about handoffs from one access point to the other, and manage connections over the access points. It's a lot of overhead," says Michael Jude, research director for Enterprise Management Associates. "With AirFlow, you basically have one [big] access point with remote antennas. What tickles my fancy, as a former electrical engineer, is that it makes deploying WLANs almost stupidly simple."

The AirFlow product line consists of either the AirSwitch or AirServer, coupled with AirHubs, to which connect WLAN clients, such as notebooks, with WLAN adapters. AirHubs can connect via Ethernet to a 12-port AirSwitch mounted in a wiring closet.

Alternatively, AirHubs can plug into available ports on the LAN switch and pass over the LAN to an AirServer, which attaches directly to the network core in the data center. The AirServer is simply an AirSwitch without the 12 Ethernet ports.

But this description also fits a flock of competing vendors, ranging from start-ups such as Airespace, to established players such as Symbol Technologies and networking giants such as Cisco. They all seek to link WLAN access points to a Layer 3 or Layer 4 switch with a software stack designed to handle issues such as wireless authentication and security, and roaming across different subnets.

Click to see: The AirFlow family

But AirFlow introduces something new. The company has filed 12 patents for technology that splits an access point logically in two. AirFlow shifts the media access control (MAC) layer of the IEEE 802.11 WLAN specification from the access point to the central switch. The MAC handles such functions as request-to-send and clear-to-send. All these functions now are centralized on the switch. What remains in the AirHub is only the radio frequency component, the physical layer of an 802.11 WLAN.

Essentially, the switch becomes the access point, with numerous distributed antennas - the AirHubs - that blanket a floor or building with radio waves. One implication is that you can plug in as many 802.11b AirHubs as you need to cover a floor and assign those devices the same channel, say, Channel 1, for data. Then you can install the same number of AirHubs, next to the existing ones, and assign them, for example, Channel 11, which you can dedicate to wireless voice over IP. There is no radio interference and therefore no need to measure radio signals, jigger with channel assignments or move the AirHubs around.

Jude says the technology is complex, even though users see almost nothing of that complexity. One possible result, he says, is that this added complexity in the switch might make it relatively unreliable compared to a conventional access point. The AirFlow executives, he says, assured him the device is highly reliable.