Products delivering fixed mobile convergence let enterprise administrators fully integrate mobile phones with the PBX, extending the reach and power of the companies' telephony infrastructure to mobile users both in the office and on the road. By granting seamless mobility between voice over Wi-Fi and cellular voice service, companies could potentially see a dramatic decrease in the amount of mobile minutes used. However, implementers must evaluate whether these cost savings are offset by upgrades likely needed to the PBX, wireless network and mobile smartphone fleet in order for the initiative to be successful.
At the heart of the matter, FMC (fixed mobile convergence) solutions fully integrate mobile phones into the corporate PBX. With FMC, mobile users can be reached on their smartphone by dialing a corporate extension (the same extension that is likely already assigned to a desk phone), can easily place calls using either the corporate extension caller ID or the mobile phone's personality, can leverage 4-digit dialing for other enterprise extensions, and can access the corporate telephony directory for lookups.
However, FMC solutions will also leverage available Wi-Fi networks for cost savings, allowing the user to seamlessly use voice over Wi-Fi technology when in the office-or, in some cases, remotely-which could potentially save the enterprise much money on cellular minutes used up when the employee is in actually in-pocket. Therefore, FMC solutions need to have the intelligence to locate and connect a user's smartphone no matter if they are connected via Wi-Fi or the cellular network, and the solutions must be able to seamlessly move calls between the networks when the user moves in and out of the building.
In my recent tests of FMC products from Agito Networks and DiVitas Networks, I found that the solutions available today deliver on all these fronts, doing so in a fashion that does not require the smartphones to have mobile data services, although some features will be missing without such service. Specifically, directory lookups when connected to the cellular network will not be possible without data services.
DiVitas has also taken some baby steps towards implementing a richer mobile unified communications experience that will require the end point to have cellular data service. Specifically, DiVitas' client application now offers presence capabilities-identifying which other DiVitas users are available at the moment, what forms of communications are currently being accepted, and passing along a status message-as well as instant text messaging service between Divitas users.
To enable FMC in the enterprise, customers will need to have a central PBX that is SIP-enabled, because the FMC controller will need to trunk into the PBX and the clients may connect directly to the PBX as well, depending on which solution we are talking about. The smartphone's relationship to the PBX will depend on the FMC solution in question.
DiVitas fully utilizes trunk-side connectivity between the pieces of the FMC solutions and the PBX, meaning that the phones register with the FMC server component, which in turn proxies communications to the PBX. All call initialization and tear down, as well as the call media payload, go through the FMC server. This arrangement should lead to a wider array of supported PBXes (as the PBX just needs to support SIP trunks), but in essence, a system administrator will then be managing two PBXes (each with their own call routing patterns and voicemail capabilities) as the FMC server is by necessity its own PBX.
Agito Networks, on the other hand, utilizes both trunk- and line-side connectivity. Call management traffic trunks through the FMC server, while the media payload goes directly to the PBX or the other end of the call (depending on the type of call). Line-side connectivity requires much work on the backend from the FMC vendor, as patches to the PBX could break the connectivity. But careful planning of PBX upgrades and collaboration with FMC support should alleviate these concerns. So line-side connectivity will likely limit the number of PBXes that are supported by the FMC vendor, but in theory should allow better use of the native features of those PBX solutions that are supported.