This new offering from Sprint and Tango is the first glimmer of an intelligent interface to the mobile world.

While much of the world's understanding about fixed mobile convergence is stuck on premises-based solutions that transparently whisk calls back and forth between Wi-Fi and cellular networks, there are carrier solutions that look to address many of the same requirements. T-Mobile has gotten some traction with their dual mode Wi-Fi Calling for Business service that uses the same unlicensed mobile access (UMA) technology as their consumer focused Unlimited Hot Spot Calling.However, Sprint is the only mobile operator who has actually made changes to their core network to incorporate an enterprise FMC service. That service, called Mobile Integration, takes a unique approach to FMC and can offer significant savings to enterprise users. They have now partnered with Tango Networks to expand the potential market for Mobile Integration and incorporated significant new functionality for mobile unified communications.

Sprint's Mobile Integration Sprint's Mobile Integration is a network-based FMC service that initially worked only with Avaya and Cisco IP PBXs. The configuration requires an MPLS network connection from the PBX to the Sprint network, and an Avaya or Cisco supplied interface device to support the MPLS network connection. Sprint then stores the mobile numbers of all of the Mobile Integration subscribers to identify their calls for special handling.

When another PBX station places a call to a Mobile Integration subscriber, the PBX will ring the user's desk phone and simultaneously forward a call request over the MPLS connection to the Sprint network to ring their mobile (i.e. "simultaneous ring"); the user can answer the call on either device. If the call is answered on the mobile, the PBX forwards the media (i.e. voice packets) over the MPLS network to Sprint who converts it to a traditional circuit switched cellular call. The key advantage is that Sprint treats that call as a free on-network mobile call.

If one Mobile Integration subscriber calls another, Sprint rings the mobile device and simultaneously sends a call request over the MPLS network to the PBX to ring their desk set. If the user answers on the mobile, an alert message is sent to the PBX so the call can be captured in the call detail recording. If the user answers on the desk set, Sprint connects the call to the PBX over the MPLS connection. In either case, the call is treated as a free on-net mobile call.

Sprint's basic charge for the Mobile Integration is $4.95 per user per month; there is also a charge for the MPLS network connection and for the premises-based interface device. However, if a significant portion of the mobile usage is calls to/from the PBX, those costs can easily be offset by reducing the cellular plan minutes. Probably the biggest obstacle will be trying to explain something as convoluted as this to cellular buyers, many of whom will think "MPLS" is a contraction for "Minneapolis"!

The Tango Factor Mobile Integration has been around for a while, and we've featured Sprint in a number of our FMC panels at VoiceCon over the years. The initial benefit of the Tango connection is that it will expand the range of PBX systems the service can support. Tango's product is PBX agnostic and designed to provide many of the same features as Mobile Integration, in particular, single number access, single voicemail, and number protection (i.e. keeping the mobile number unknown). The configuration calls for the installation of a central office device called the Abrazo C in the mobile operator's network and a companion device called the Abrazo E at the customer's location. The two Abrazos exchange signaling messages to provide simultaneous ringing and to route calls; the original concept did not include an MPLS connection from the customer to the mobile operator.

While ingenious in design, the Tango product has languished as the carriers chafed at the idea of introducing a new element in their core network, particularly one that did not address consumer services, the only market they pay any attention to. Sprint obviously sees Tango as a way to enhance the Mobile Integration offering.

According to Al Leo, VP of Business Development at Tango, Sprint has now embraced the concept, implemented the Abrazo C in their network, and married the Tango capability to Mobile Integration. The major advantage of the new service, formally called Tango-Enabled Mobile Integration, is that it can now be offered to users on all PBX platforms, not just Avaya and Cisco. This is particularly attractive to customers with mixed PBX environments. To use the service, the customer will have to install an Abrazo E, but a single Abrazo E will support users in multiple locations and on a variety of PBXs. Mobile calls to/from the PBX will still be routed over an MPLS connection, and the financial advantage of treating them as on-net mobile calls will be maintained.

While expanding the base of supported PBXs for the Mobile Integration service is the basic story, the Tango implementation adds an important increase in functionality as well. The communication between the Abrazo C in Sprint's network and the Abrazo E in the customer's site can provide presence and location status of the mobile devices. For the moment that's a one-way street (i.e. presence status about the mobile is provided to wired stations, but the presence status of those wired stations is not provided to the mobile), however, this is a major step forward. Up until this point, the interface between the user and the mobile operator has been as functional and transparent as a brick wall, but now for the first time we are getting useful presence information about mobile users. The location information is cell tower identification rather than GPS location, but that is way better than nothing.

Conclusion Our overall vision of the network going forward is an all-IP core with SIP-based signaling that not only supports integrated voice, text, and video communications but allows presence and other UC capabilities to be extended transparently between all end devices across all networks, public or private. Up until now, that vision has come to a screeching halt when we got to the mobile operators. While not "all-IP" at this stage of the game, this new offering from Sprint and Tango is the first glimmer of an intelligent interface to the mobile world.

As I have noted on numerous occasions, the leading-edge ideas in enterprise mobile services are coming from the smaller operators rather than the behemoths (i.e. AT&T and Verizon). While there is no Wi-Fi/cellular element, Sprint and Tango are providing a cost saving solution to users with MPLS and added intelligence in the network. This is a complex configuration however, and one that will require the cooperation of the PBX, wide area networking, and mobility groups. The biggest challenge may be to work through so many organizational silos.

While the addition of Tango expands the available market for Sprint's Mobile Integration to all PBX systems, from a mobile UC perspective, the ability to provide presence and location status for mobile devices is a real breakthrough. Sprint still has to work through their ongoing business difficulties and convince customers that their WiMAX initiative is a viable 4G solution, but they have really raised the bar in mobile UC.This new offering from Sprint and Tango is the first glimmer of an intelligent interface to the mobile world.