The Inevitability of VoWi-Fi

See how one company's move to an IP PBX and an upgrade of its Wi-Fi infrastructure made it a no-brainer to start sending voice traffic over the WLAN.

By Gerry Blackwell | Posted May 27, 2005
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Voice over Wi-Fi (VoWi-Fi) is rarely the killer app for a corporate wireless LAN implementation, but as WLAN and IP PBX penetration increases, as voice over WLAN technology improves and prices come down, more and more companies will start putting voice over the air.

After all, why not? If you already have a WLAN and an IP PBX, adding VoWi-Fi seems a small step with some potentially big pay-offs. That was the thinking at Commercial Alcohols Inc. (ComAl), which late last year took the first baby step towards what IT manager Chris Thomas says will eventually be widespread use of VoWi-Fi in the company.

"The initial thought was just that we had our existing wireless network from Aruba and it would be worthwhile to try and leverage that technology to do some other things besides data," Thomas says. Equipping warehouse workers at the company's main plant with mobile phones hooked into the PBX looked like a natural.

Commercial Alcohols, based in Brampton, Canada near Toronto, is the country's largest producer of ethanol for fuel. Ethanol is a renewable resource—ComAl produces it from corn—that can be added to gasoline, reducing both consumption of petroleum-based products and greenhouse gas emissions. The company has 225 employees spread around eight offices: six in Canada, two in the U.S.

A few things had to come together before Thomas could begin to consider deploying VoWi-Fi. The first step was replacing Cisco Wi-Fi gear in all offices with centrally managed infrastructure from Aruba Networks. ComAl had installed Wi-Fi in its offices for the usual reasons—to allow mobile employees to log into the corporate LAN from their laptops and collect e-mail or access other network resources.

The move to Aruba last spring came as the company grew and spread further afield with expansion and acquisitions. "The [Cisco] access points we had were fat access points," Thomas explains. "We had to configure each one separately [in the field]. Initially, there were only five, so it wasn't a big deal to manage, but as the company grew, over time we felt it would be cumbersome to manage."

ComAl installed an Aruba wireless switch at its Brampton head office. The switch controls all the access points at that office. Access points at the branch offices are also tied back to the switch over the company's high-speed private wide area network. When a traveling employee visiting a branch logs on through the WLAN, the network sees him as logging on in Brampton.

More importantly, Aruba's centralized network architecture and "thin access point" approach means Thomas's team can configure, maintain and install upgrades to all access points at the same time from the head office. "It just made it a lot easier to manage the wireless infrastructure," Thomas says.

The next piece of the puzzle was the decision to switch to an IP PBX at the head office. Last December, Thomas oversaw the implementation of a Business Communications Manager (BCM) system from Nortel Networks. BCM is Nortel's IP PBX for small and medium size enterprises. With the decision to go IP for telephony, it was an easy—though not inexpensive—decision to begin experimenting with VoWi-Fi.

A few employees in the warehouse at the company's main Brampton plant—shipping and maintenance personnel—were carrying two-way radios to communicate with employees in the office or at the loading dock. But if a call came in from another office or from one of the trucking firms the company deals with, the switchboard would have to put the call on hold and reach the employee on his walkie-talkie. The employee would then have to leave whatever he was doing and go to the nearest phone to take the call.

Thomas installed four additional access points to extend Wi-Fi coverage throughout the warehouse, and equipped three employees with Nortel 2211 WLAN Handsets (made by Spectralink) which work with the BCM. The phones cost about $400 apiece, the access points about $520 each. "It was $5,000 by the time we had all the hardware installed and put in additional cabling," Thomas says. "So it wasn't necessarily the cheapest solution."

It does pay dividends, though. Warehouse employees who get calls from outside the office can now take them on the Nortel 2211s, which they wear clipped to their belts—much as they did the two-way radios. It saves them the time it took to get to a telephone in the past. It also saves the switchboard time and effort—the mobile phones are tied into the BCM and function like any other extension—and it means suppliers and others don't have to wait on hold.

"It was really just a way to streamline telephone communications for those people," Thomas says. "It's certainly easier for them to get their calls now."

The investment in Wi-Fi infrastructure in the warehouse will also deliver more than just VoWi-Fi. The company plans to equip warehouse workers with handheld devices to communicate inventory and shipping data directly to the company's central servers from the floor. The technology was already in use at a smaller ethanol company ComAl recently acquired. Thomas expects to implement it at the head office later this year.

The experience with VoWi-Fi in the Brampton plant will also put ComAl in a good position to implement its larger plan for the technology. Traveling executives and other mobile employees currently use the WLANs in the branch offices to access the corporate LAN from laptops when they're visiting. In future, they'll also be able make and take calls when they're in any office as if they were in their own office. ComAl may also equip non-traveling employees who, like the Brampton warehouse workers, are frequently mobile around the office.

A few more pieces of the puzzle will have to come together first, though. The company has now standardized on the BCM platform and will slowly migrate all offices to IP telephony using the Nortel technology. It will also have to put Aruba switches in every office.

"When we put an access point at a branch office now, it presents itself to the system as if it's on the Brampton network," Thomas explains. "That's fine for data, because all the servers are located in Brampton. But if you have an IP phone at a remote location, [all the calls] would first go to Brampton, then back out, creating unnecessary network traffic."

The Aruba switches could all be linked to maintain the network management advantages. Still, the need for switches in all offices means that upgrading the company's network infrastructure to accommodate wider use of VoWi-Fi won't be cheap. ComAl is not in a huge rush, though. "We'll add phones for travelers over the next couple of years," Thomas says.

By then, handset prices will have come down, and convenient dual-mode cellular/VoWi-Fi models should be readily available.

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