To finish up our mini-series on how at how IP Multimedia Subsystem (IMS) architectures and Unlicensed Mobile Access (UMA) technology can complement each other, we'll wrap up today with an interview with Emma Mohr-McClune, senior analyst for enterprise mobility at Current Analysis, about the state of fixed mobile convergence (FMC).

Mohr-McClune points out that British Telecom is the only service provider so far, to offer FMC services based on UMA. However, she points out that many other providers, including France Telecom, Telefonica and Deutsche Telekom, are expected to offer UMA-based services later this year. One major hurdle that stands in the way of commercial services is the lack of dual-mode mobile handsets capable of delivering the service.

Mohr-McClune has defined the difference between FMC and fixed mobile substitution (FMS) quite clearly. To qualify as an FMC service, she concludes that voice or data traffic must move from a mobile (i.e. GSM) network to or from a wireline network. She defines FMS as a service that "never touches the wireline network." She concludes that many "homezone" services are really FMS because they rely on the mobile network for call control.

She also notes that while some PBX/IP-PBX based services offer call control by switching to and from the wireless access point and mobile networks, these configurations also can provide PBX-like telephony features to the dual mode handset. While she qualifies this solution as an FMC alternative, she observes that there are no network-based commercial services today that offer the same capability.

Mohr-McClune has published an advisory report titled "FMC - Did We Miss It?" and you can read it here.

Our thanks to Mohr-McClune for her insights. Next time, we'll move to another topic but if you have comments about IMS, UMA, FMC or FMS, please drop us a note by clicking on our contact information below.

Steve Taylor is president of Distributed Networking Associates and publisher/editor-in-chief of Webtorials. Larry Hettick is a principal analyst at Current Analysis.