Tango Offers Carrier-Friendly Bridge Over The Fixed-Mobile GapTango Offers Carrier-Friendly Bridge Over The Fixed-Mobile Gap

A new software offering from a relatively obscure two-year-old enterprise mobility startup may help pierce the iron gate that has separated businesses from true fixed-mobile convergence, or unifying deskbound voice calling with mobile devices such as cellular phones and Wi-Fi-enabled smartphones.

Tango Networks has released a new version of its Abrazo suite that allows "voice-call continuity," or seamless handoffs between cellular networks and in-building Wi-Fi networks.

"This announcement really is the holy grail of what fixed-mobile convergence is all about," said Philippe Winthrop, research director for wireless and mobility at the Aberdeen Group.

Alastair Westgarth, who became president and CEO of Tango last October, says that the beauty of the new software (Release 4 of Abrazo, in Tango's parlance) is that it separates dual-mode (Wi-Fi plus cellular) systems from fixed-mobile convergence -- a distinction often lost in the minds of both users and the major carriers.

"We're now giving the carriers the capability of walking into fixed-mobile with or without dual-mode [capability]," says Westgarth, "or with the choice of introducing dual-mode at some point in the future. [Abrazo Release 4] doesn't force them to make a dual-mode decision while making a fixed-mobile decision."

The big U.S. wireless carriers have resisted moving toward dual-mode devices and services for years, frustrating their business customers in the process and in some cases actively blocking the technology for fear of eroding their cellular business. T-Mobile is the only one of the Big 4 carriers that has introduced dual-mode service to date.

Still, research from the Aberdeen Group shows that 30% of companies are planning on deploying voice services over dual-mode devices, including Wi-Fi enabled smartphones, over the next 12 months. Infonetics Research has predicted that worldwide revenue from Wi-Fi-enabled phones will grow by double digits in the next three years. All the big carriers, including Verizon Wireless and AT&T, are currently making plans to embrace or offer some form of fixed-mobile service over the next few years, while big infrastructure providers such as Cisco have come out with grand "unified communications" product lines that encompass, in many cases, voice, e-mail, instant messaging, "presence" and location-based services, and so on. To date, however, enterprises have been slow to move toward such systems because they often entail giving up some control, particularly over mobile devices.

"The classic [fixed-mobile] architecture has a server for voice-call continuity located up in the carrier network," explains Westgarth, "and at the end of the day what the carrier is doing is controlling dual-mode access into the enterprise over either the public switched network or over enterprise access points."

The premise of the new Abrazo software, he adds, is "if you're offering an enterprise service, you'd like to control it with the same policies as your PBX through the same set of routers or what have you."

Other fixed-mobile startups, including Agito Networks and DiVitas Networks, now offer similar technology that shifts control over fixed-mobile services from the carriers to the enterprise IT department. IP-telephony provider Avaya recently rolled out a dual-mode application designed to hand off calls between corporate Wi-Fi networks and cellular networks on Nokia E-series devices, while Qualcomm and Nortel last month said they will team to provide a dual-mode application for mobile devices. In general these offerings are in many ways the carriers' worst nightmare, bringing the power and affordability of voice-over-Wi-Fi (now dubbed in some circles "VoFi") to mobile devices and inevitably eroding the carriers' margins.

Tango's approach, on the other hand, while not offering any real technological breakthroughs, takes an inclusive approach that, in theory, will benefit enterprises, carriers, and end users.

Despite operators' skepticism, says Winthrop, the spread of Wi-Fi/cellular devices is both inevitable and beneficial: "This will create opportunities for the carriers, as users take their dual-mode devices with them, and bam! switch over to cellular. End users are going to be talking even more, and by default that will increase minutes for the carriers."