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Wireless Integration: VeriSign's Approach

Everybody, it seems, is working on a solution to integrate mobile and Wi-Fi-based telephony. One of latest to enter the fray is VeriSign, a provider of secure network services to both wireless and wireline carriers, including managing roaming between cellular carriers. VeriSign recently announced field trials of its wireless integration solution at three U.S. university campuses.

Most such solutions are targeted at enterprises and government agencies. They involve installing proprietary hardware and software and establishing direct relationships with one or more cellular carriers. A prime example is the Enterprise Seamless Mobility solution from Motorola, Avaya and others.

VeriSign, however, is testing a different kind of service-based approach. When trial users are within range of their university's existing Wi-Fi network, they'll make mobile calls from a dual-mode handset over the WLAN and, if necessary, through a gateway to the PSTN . When they roam out of the Wi-Fi coverage, VeriSign automatically transfers the call to a cellular carrier.

"They'll be able to access a cellular network on demand," explains Tom Kershaw, VeriSign's vice president of next generation services. "You don't need a [cellular] contract because we have existing relationships with the mobile community. The design is to be network-agnostic. We'll grab access to the network that has the highest quality connection."

A customer with an existing Wi-Fi network and VoIP system simply needs to make a virtual private network (VPN) connection from their IP network to a VeriSign network operations center. VeriSign does the rest, using a mix of proprietary and standard technology, including translating between the Session Initiation Protocol (SIP) signaling used on IP-based phone networks and Signaling System 7 (SS7) used on cellular networks. It can even provide PSTN gateway services if the customer is just getting started in VoIP.

VeriSign is testing the technology at the University of Michigan, Northwestern University and Texas A&M. Universities are prime candidates for this kind of service, Kershaw says. The user base is more open to new modes of communications than in mainstream enterprises, and many campuses already have ubiquitous Wi-Fi coverage.

The business case, while it hasn't been fully worked out yet, could be compelling. For most mobile calls — as many as 80 percent, VeriSign figures — university users would remain within Wi-Fi coverage throughout. This means that schools that provide staff and faculty with cellular phones could theoretically save something approaching 80 percent of their airtime costs. Universities that don't currently provide mobile phones could now offer mobility without incurring huge new costs.

Mobility is certainly a powerful inducement. The University of Michigan owns a 38,000-line traditional phone system. It also has 1,500 VoIP desktop phone sets. It installed the VoIP system to replace Centrex lines. Given that the traditional phone system is of relatively recent vintage, the lure of VoIP is not enough on its own to make the school want to replace the system, explains director of communications systems Andy Palms. Wireless integration on the VeriSign model ups the ante, though.

"A lot of our folks are very mobile, and they spend a fair amount of time off campus," Palms says. "They would prefer it if they could walk around with their university telephone in their pocket. With this service, we could instantly use our Wi-Fi capability to provide their business telephone service and, to a degree, effectively eliminate the need for desktop phones."

A Wi-Fi phone alone would not be attractive enough to his users, he adds. It would have to be a dual-mode phone that they could also use when off campus. The potential business case: fewer costly phone company lines, better service to the community.

The VeriSign service is not just for universities, though, Kershaw hastens to point out. "It applies to consumers, to small business users and large businesses too," he says. "They'd all be able to get more use out of those mobile appliances. That's something every market cares about."

The availability of "mobile appliances" capable of both cellular and Wi-Fi telephony is the main delay factor in bringing wireless integration to a wider market, Kershaw says. For the trials, VeriSign is initially using Hewlett-Packard iPAQ PDA phones running SIP phone client software. They're expensive and not ideal for many users who are accustomed to using much smaller cellular handsets.

Asked when the first commercial customers might be up and running using the VeriSign service, Kershaw says, "It all depends on the handsets. They have to be economical and stable and support long talk times. That's really the gating factor right now. We're closely tracking handset availability." He expects the dual-mode handset market to take off in the fourth quarter this year.

At the time of writing, the trials were in the very early stages. UofM had only deployed two of the iPAQ devices, and was looking to hand out 25 or 30 more within a few weeks. "It sounds small, and it is pretty small," Palms says. "But it's not about scaling. This is really a trial to get the technology to work, rather than to get it to scale." Kershaw estimates there will only be a few hundred devices deployed across all three test sites.

The technical issues are one thing. Human behavior and market issues are another. One of the thorniest is how to hand off calls between Wi-Fi and cellular. From the technical point of view, VeriSign could do it seamlessly, Kershaw says. The question is whether users will want that. Or will they prefer to be notified when they're about to wander out of Wi-Fi coverage — and notified of what they'll be charged when they do — so they can end the call if they don't want to pay the airtime charges?

"What if the tariff structure is vastly different [than for regular cellular calls on a plan] and you're paying per minute?" Kershaw says. "You might walk up the driveway to take the garbage out and rack up a $5 phone bill."

At issue, in part, are the tolls to be charged. Since users won't have cellular contracts and VeriSign will use whichever network is available, does that mean every call will in effect be a roaming call and be charged accordingly, Palms wonders? Judging by Kershaw's comments, VeriSign itself doesn't know yet. Some users stand to save a lot by using Wi-Fi instead of cellular, but if they're charged roaming rates whenever they do have to use a cellular network, will that cancel out the savings?

One of the unknowns is the attitude of cellular carriers to this approach — and ultimately their role in bringing it to market. VeriSign already has business relations and network interconnections with most major cellular carriers, but it seems unlikely they will be content to give VeriSign customers access to their networks on a par with their own customers. They will presumably want to charge some premium, even it's not as big a premium as they charge customers of competing cellular carriers.

This is no doubt one reason VeriSign is talking about providing the integration service on a wholesale basis to carriers. As Kershaw points out, it means they would now be able to offer attractive multi-mode services — high-speed Internet, wireline and Wi-Fi VoIP, and cellular. Throw in video, and you have a quadruple play.