There is no doubt that users want to add mobility to their unified communications. We now have a variety of fixed-mobile convergence (FMC) solutions, and as often in the case in emerging technologies, the leading edge capabilities are coming from the smaller, more aggressive players. During last week’s InterOp convention in Las Vegas, Cisco and Nokia announced a spate of trails for their mobile unified communications solution, but the news was about numbers, not capabilities. While most of the other solutions have advanced to an automatic hand-off, Cisco’s still depends on the user transferring the call manually. That function is critical not just for the user convenience, but to ensure that calls are always carried on the most cost-effective service.

There are three key factors that differentiate fixed mobile convergence solutions: control, functionality, and integration. Control deals with whether the solution is managed as part of a carrier service like T-Mobile’s Hotspot@Home or by the customer’s equipment. As the cellular carriers have shown little interest in delivering enterprise FMC, an opportunity has been created for a variety of user-based solutions. In terms of functionality, the offerings differentiate themselves by providing either a basic voice call handoff or some level of mobilized UC. Mobile UC solutions offer features like presence-capable remote directory, visual voicemail, and 4-digit extension dialing. Integration defines whether a call is handed off automatically from the private to the cellular network, or if the user must invoke a manual command to affect the transfer.

Whether the carrier or the customer controls the solution, the goal is a fully functional mobile UC capability where calls are automatically handed off and the user can move transparently between the private and the public networks. That vision has persisted since the first ill-fated Seamless Convergence product was announced by Avaya, Motorola, and Proxim in mid-2004. In that case the cellular partner, Cingular, refused to certify the dual-mode Motorola CN620 handsets that were the basis of the offering, and Seamless Convergence died a slow death.

The Start-Ups

The idea of customer-based FMC was resurrected by DiVitas Networks in 2005, with a solution that could work with any TDM or IP-based PBX. The DiVitas Server connects to the PBX and controls a network of dual mode Wi-Fi/cellular handsets with special client software DiVitas provides. When a Wi-Fi connected station begins to move out the wireless LAN coverage area, the DiVitas Server instructs the PBX to dial the user’s cellular number, and the call is automatically transferred to that connection. The mobile client also offers a range of UC capabilities including presence-based directory and visual voicemail. The user is accessible at one number, and since the network selection is automatic, you are assured the call will be routed over the less-expensive WLAN access if it is available. DiVitas President and CEO, Vivek Khuller, notes that with a manual solution, there is no way of ensuring that the user is not simple using the cellular network, even when they are in range of the WLAN.

Another start-up, Agito Networks, is now offering a solution similar to DiVitas. Agito has a similar configuration and feature set, but with some important differences. According to Co-Founder and Vice President of Marketing Pejman Roshan, Agito’s Roam Anywhere Mobility Router uses a location “metric”, to decide when to make the Wi-Fi to cellular hand-off decision. During the system set up, the user takes a radio snap-shot of the signal conditions at the building exits, and when the system senses that a user is moving towards an exit, it triggers the hand-off. Signal strength he argues can vary widely so their location-based approach provides a more foolproof hand-off. Mr. Roshan also claims that their product interfaces to the customer’s IP PBX rather than switching the call itself, and so is easier to deploy. DiVitas will argue to the contrary, but that Cisco WLAN user now has two alternatives getting an automatic hand-off capability. 

The IP PBX Vendors

The other IP PBX vendors have also been rolling out automated hand-off solutions, though the level of UC feature integration varies by product. Avaya has followed up their Seamless Convergence debacle with a string of mobile UC capabilities. Once you cut through the thicket of incomprehensible product names for which Avaya is famous, you find that they too can support a range of mobile UC capabilities in a solution that features automatic hand-offs and tight coupling with Avaya’s desktop UC solutions.

Siemens also offers an automatic hand-off and a line up of mobile UC capabilities in their HiPath MobileConnect offering. Like Avaya’s solution, MobileConnect couples tightly with their OpenScape unified communications solution, and Siemens also offers its own WLAN switch product. Having acquired Chantry Networks in 2005, Siemens now has all of the elements for delivering mobile UC in-house. While they do have a software client for dual mode Wi-Fi cellular handsets, they also manufacture their own line of optiPoint WLAN-only handsets.

Nortel and NEC America both depend on Firsthand Technologies for their mobile UC solution, and like Cisco, they too have to depend on user interaction to hand off calls. Reports indicate that an automatic hand-off capability is due from Firsthand by the end of the year.

WLAN Switch Vendors

While most of the activity in FMC is coming from the PBX vendors and start-ups like DiVitas and Agito, WLAN switch vendor Aruba Networks is throwing its hat into the ring. Aruba is active on a couple of fronts. First, they have been testing the capability to allow T-Mobile’s Unlicensed Mobile Access (UMA) based HotSpot@Home product to work with their WLAN switch product. While HotSpot@Home is essentially a consumer offering, Aruba has been able to trick the UMA-capable Wi-Fi/cellular handsets to associate with their centrally controlled thin access points when they come within range of an Aruba WLAN. Once associated with the Aruba network, HotSpot@Home clients can roam anywhere within that WLAN switch network, and the call is transparently handed off from access point to access point. So a user could roam from the cellular network to the private network, and then roam anywhere within the private network.

Aruba is now looking to add a capability similar to DiVitas and Agito that would allow enterprise Wi-Fi/cellular handsets to roam seamlessly between the cellular and WLAN environments. Rather than building a separate server, the Aruba approach would integrate that capability on their Mobility Controllers, the servers that control their network of thin access points. According to Aruba Co-Founder Keerti Melkote, that functionality belongs in the WLAN, not an auxiliary controller, and SIP-based signaling will allow them to interface with a variety of IP PBXs. Mr. Melkote notes that the WLAN switch has the clearest view of the WLAN environment, and with its integrated location capabilities, it can make the most informed decision about when to transition the caller to the cellular network.

Conclusion

The great thing about mobility is that you don’t have to sell users on the convenience. Unified communications is increasing the functionality of the communications network, and an increasingly mobile workforce is looking to have those same capabilities available when they walk out the door. The solution must address user features and convenience but also address network control and the business requirement of ensuring that the call is always sent over the most cost-effective service available. It seems that it’s the little guys who are leading the rush.