Start-up talks up voice for WLANs

FRAMINGHAM (10/03/2003) - Stop thinking about wireless LANs (WLANs) for data and start thinking about them for wireless voice.

That's the pitch from the latest WLAN start-up, Meru Networks Inc., which this week is shipping an access point and controller intended to make wireless voice-over-Internet Protocol (IP) practical for corporations.

The devices run Meru's Air Traffic Controller, which includes algorithms designed to boost the efficiency of any 802.11 WLAN and optimize it for voice traffic. The software does this by exploiting some lesser-known or less-used features of the 802.11 protocol, says Kamal Anand, vice president for marketing and sales.

"There is not a strong business case today for having WLANs throughout an enterprise," he says. "But voice [over wireless] will make that case."

Anand says Air Traffic Controller does three things for a WLAN:

* Boosts the number of users who can use an access point without performance loss from less than 20 to nearly 100.

* Automatically detects voice calls, makes a set of adjustments for them and gives voice traffic priority on the radio links.

* Slashes the time needed to hand off an end user, or a call, from one access point to another from around 300 milliseconds to nearly zero.

The 802.11 protocol accesses the radio wave via a contention technique: if one client detects another, it will back off and try again. Meru's algorithms make this contention a highly systematic process, orchestrating connectivity for scores of WLAN clients to a single access point.

So instead of all the clients "speaking at once," the software lets each one speak in turn, Anand says. This results in less delay and improved performance.

The software prioritizes voice traffic by detecting a voice call via Session Initiation Protocol, and then allocates bandwidth accordingly.

The company's software streamlines handoffs by grouping multiple Meru access points into one "virtual" access point with one Basic Service Set Identifier, which is the media-access-control address. The Meru algorithms let its software jump ahead to the next radio device, anticipating the moving WLAN client. The software sidesteps the need to completely set up and tear down handoffs between each separate access point.

The Meru controller works like the emerging class of WLAN switches rolled out in recent months by a slew of other companies, which centralizes authentication, encryption, management and rogue access-point detection. The controller plugs in via Gigabit Ethernet ports to a core switch; a discovery protocol lets the Meru access points find their way to the controller over the existing corporate network.

Access points have a list price of US$595; controllers cost $8,000.

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