The basic business phone can be a real pain. You’re not at your desk all day but your phone is, so callers get voice mail, everyone plays phone tag, and critical conversations get delayed. Callers try your cell phone, but if reception in your building is spotty, you miss the call.
Why can’t your office phone go with you as you move throughout your building or across campus? In fact, it can. The convergence of two rising technologies within the enterprise makes the office phone portable: VoIP telephony and 802.11 wireless LANs.
Chances are that your enterprise is keeping a close eye on these trends. It’s probably considering replacing analog PBX phone systems with VoIP, and it just might be considering adding wireless LANs to support mobile devices within your building or campus. So why not combine the two? IT is well aware that it can work together to carry voice traffic over a wireless LAN so that mobile staff, such as maintenance workers, executives, and HR reps, can make all their calls anywhere within the facility while avoiding pricey cell phone service.
At first glance, the combination seems like an easy fit, but adding voice to wireless LANs demands strategic thinking and a unique implementation strategy. The reality is, costs are steep and deployment is complex.
“A wireless LAN for voice costs about double what a data-only one costs,” notes Gartner analyst Ian Keene, although he expects the cost to decline over time. Because VoIP and 802.11 technologies are relatively immature, many businesses are reluctant to commit a critical communications infrastructure to them until they have proven themselves. What’s more, enterprises that have recently invested in a telecom infrastructure won’t be compelled to replace it until the current investment becomes obsolete. Traditional enterprises mostly view voice over wireless as something to explore for future use.
Nevertheless, many businesses are moving to wireless VoIP. They tend to be in highly mobile industries, such as hospitals and warehousing, and typically are replacing their entire telecom infrastructure, says Ben Guderian, director of strategic marketing at SpectraLink, a provider of voice-over-wireless handsets.
Simple Idea, Complex Execution
The technology behind voice over wireless — varyingly referred to as wireless IP telephony, wireless VoIP, and Wi-Fi telephony — is straightforward. Mobile handsets connect to the network over wireless access points, routing the voice traffic to the telephony server or digital PBX in the same way that VoIP handsets connect to the network over Ethernet cables, routing their voice traffic to the telephony server or digital PBX (see “Add-On Server Routes Calls and Manages Voice Traffic,” page 48). That apparent simplicity is why many enterprises consider implementing voice over wireless when they implement a VoIP system, Keene notes. Chances are they’re also deploying wireless access points for data usage, so they believe that most of the infrastructure required to make VoIP mobile is already in place. “On the face of it, it looks like a no-brainer,” he says. But in reality, IT faces several deployment hurdles.
Wireless LANs for voice require denser access-point placement to reduce contention for the access point’s bandwidth and require deployment in areas like hallways, elevator shafts, and facilities service areas in which data usage would not occur. That means greater hardware and installation costs.
