There are two classes of FMC solutions. Behind-the-firewall servers or carrier-based services, both enabling mobile phones with Wi-Fi adapters (so-called dual-mode phones) to link with corporate IP PBXs via cellular or Wi-Fi networks. The first is from vendors include start-ups such as Agito, DiVitas Networks and Tango Networks and established vendors like Avaya, NEC and Siemens. In the United States, T-Mobile's @home service, base on the Unlicensed Mobile Access (UMA) standard and Kineto Networks hardware, is the leading offering of the second type.
In both, the FMC server works with a client application to detect when a user is moving into and out of range of cellular or Wi-Fi networks. Basically, the server starts a parallel call over the alternate wireless network, mixes the audio from the two sessions, and drops the first connection.
That sounds simple enough, but it requires a kind of "cellular-grade" Wi-Fi network to provide reliable, wall-to-call coverage within the enterprise, to enforce QoS, and to handle unpredictable call volumes. Such wireless LANs are still not all that common, though that's changing and may change faster as enterprises deploy high-throughput 802.11n.
Variations on the FMC theme
Enterprises are now weighing variations on the FMC theme, says Paul DeBeasi, senior analyst for the Burton Group, a technology research firm. "There are a fair number of people doing FMC, but they're not doing it with dual-mode phones," he says. "Integrating mobile phones into the [corporate] network is going to gain more traction. It's the dominant approach that I hear people talking about now."
That often starts with improving cellular signals and coverage with some kind of indoor, distributed antenna system (DAS) throughout the enterprise. Florida Hospital in Orlando deployed a DAS from Mobile Access for improved cellular and page coverage, to ensure that doctors and others could be reliably contacted by mobile phone no matter where on the seven-campus hospital system they might be. Separately, a pervasive Cisco WLAN is the wireless backbone for some 900 Wi-Fi mobile phones (Nortel-branded devices based on Polycom's SpectraLink line) for nurses and others, linked with the PBX.
Based on current user requirements, there's not much need to combine these environments, according to Todd Frantz, the hospital's associate CTO. "For the most part, our employees don't move long distances between buildings or between sites," he says. "And my desk phone does a whole lot of things my mobile phone still won't do."