Wireless technologies have played a big role in opening up Internet access — and thus the ability to communicate with others in remote locations — to more people in more places. As communication methods converge, Wi-Fi makes it easier for you to access e-mail, instant messages, faxes, voice mail, and VoIP calls from a common interface — no matter where you might be.
Higher bandwidth and greater reliability (such as that offered by the new 802.11n standards) make voice over wireless LAN (VoWLAN) feasible. Of course, with conventional 802.11 wireless, the transmission range can limit the usefulness. But 802.16 (WiMAX) greatly expands that range, making wireless a viable "last-mile" broadband option that will compete with cable and DSL.
More and more products are coming onto the market that allow you to integrate wireless technologies into your unified communications strategy. Let's take a closer look.
Dual-mode (cellular/WLAN) phones
The next big boon to unified communications may come from cellular-wireless convergence. Mobile phones that can operate on both cellular and Wi-Fi or WiMAX networks — and switch over automatically when an 802.11 or 802.16 network is in range — could greatly reduce the cost of mobile communications for both personal and business users.
To make it happen, you not only need mobile handsets that support dual-mode communications; you also need a device on the network that can do the switching between the wireless LAN and the cellular network. Dual-mode phones are available from a number of vendors, including Cisco, Motorola, and Samsung.
In addition, enterprises are using solutions such as the RoamAnywhere appliance from Agito Networks to provide better connectivity and reduce cellular costs. These solutions allow users to connect over the wireless LAN when they're on-site at the workplace and then kick over to cellular when they leave the building — even in the middle of a call.
The system integrates into the company's IP PBX system, so they have access to many of the same sophisticated features used on desktop phones, such as dialing internal numbers by extension and the ability to transfer calls, as well as a single phone number within the building that follows them when they "go cellular." The RoamAnywhere Mobility Router monitors connections and can determine the location of each user (inside or outside the wireless LAN's range) and route the call through the Wi-Fi or cellular network accordingly.
Avaya is a leading vendor in the unified communications space and well known as a maker of IP phones. Its Unified Communications Center (UCC) software allows users to access their Exchange or Lotus Domino e-mail, voice mail, and fax messages, as well as Exchange contacts, calendars, and task lists via voice commands.
Last year, Avaya teamed with Nokia to provide dual-mode functionality with Nokia's E60, E61, and E70 model cell phones. Dubbed Avaya one-X Mobile Dual Mode, the solution lets users "hand off" calls from the internal Wi-Fi network to the cellular network by pressing a button.
DiVitas Networks is another leader in mobile convergence technologies. Its Unified Mobile Communication solution offers seamless roaming between cellular (both GSM and CDMA) and Wi-Fi networks with Windows Mobile and other popular devices, and it integrates with enterprise applications.
The DiVitas solution features a built-in PBX (and also works with an external PBX). PBX features include such standards as hold, forward, transfer, mute, and caller ID, as well as more advanced features such as visual voice mail, scheduled and ad hoc conferencing, simultaneous ring, and the ability to toggle between desktop and mobile phones.
Advantages of Wi-Fi/cellular convergence
The convergence of wireless LAN and cellular technologies has advantages above and beyond cost savings. It can also address connectivity problems that occur in some locations, whereby cell phone users get poor or no signals within their buildings. By using the Wi-Fi network internally, these users can continue their conversations without interruption when they enter the corporate building.
As the technology matures and wireless networks become even more ubiquitous than they are today, convergence is sure to become more popular. The redundancy of having both networks available increases the reliability of mobile communications, while at the same time increasing worker productivity and reducing downtime due to lack of connectivity.
Most of the convergence solutions are carrier-agnostic, so you don't have to commit to a particular cellular provider in order to use the technology. Ultimately, dual-mode phones could replace landlines and wired VoIP lines completely. But as attractive as that sounds, it's likely a long way down the road.
Obstacles to adoption
Despite the advantages, cellular/Wi-Fi convergence has been slow to take off. Even with a number of companies offering the hardware, deployment of dual-mode telephony is still a relative rarity.
One reason is reluctance on the part of the traditional cellular providers to support a technology that will reduce the number of billable minutes used by their customers. Cellular airtime is expensive for users, which means it's lucrative for the providers. Cell phone companies may not give that up without a fight.
Another obstacle is the wireless infrastructure itself. Many company Wi-Fi networks don't have the bandwidth necessary to support company-wide convergence.
Voice traffic uses more bandwidth than the data traffic for which most companies originally deployed existing Wi-Fi networks. This should become less of a problem as 802.11n standards become established and the equipment for high-speed n networks becomes more widely deployed.
Yet another challenge is battery life. Wi-Fi drains batteries quickly, as many laptop computer users have discovered. Better battery technologies for mobile handsets will be necessary in order to support Wi-Fi/cellular convergence.
Even with all these obstacles to overcome, convergence seems inevitable as more and more users demand "one-stop shopping" for their communications needs. The question is not if but when dual-mode phones will become our primary means of voice communications.
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Debra Littlejohn Shinder, MCSE, MVP is a technology consultant, trainer, and writer who has authored a number of books on computer operating systems, networking, and security. Deb is a tech editor, developmental editor, and contributor to over 20 additional books on subjects such as the Windows 2000 and Windows 2003 MCSE exams, CompTIA Security+ exam, and TruSecure's ICSA certification.