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You’re surfing the Web from a wireless laptop in an Internet café, two stories below ground, and your signal is strong. Pages are loading quickly, and the status bar in your laptop confirms that Wi-Fi strength is “excellent.” Down there, however, your cell phone is useless, registering zero bars. If only there were a service that could somehow let your phone speak Wi-Fi, allowing it to use some of the available Internet Protocol (IP) bandwidth to call anyone in your address book, anywhere in the world, as if you were using your cellular service. VeriSign operates a service that will allow you to do just that, and is currently offering the service on a trial basis to universities such as the University of Michigan, Northwestern University, and Texas A&M, and next-generation voice-over-IP (VoIP) providers. 

The service, VeriSign® Wireless IP Connect, allows participants to make or receive calls using both a Wi-Fi network or a commercial wireless carrier network while using a single device and phone number. “This service has strong potential for subscribers and carriers alike,” says Tom Kershaw, vice president of next-generation services for VeriSign. “Subscribers will be able to enjoy the quality, reliability, and features of landline service, the lower costs of VoIP service, and the convenience of mobility. Carriers, in turn, will be able to reach and retain a growing market of users who are demanding a service that combines all three of these benefits.

The University of Michigan: 
Building a Dual-Mode Network 
The University of Michigan serves over 50,000 students across its three campuses of Ann Arbor, Dearborn, and Flint, and the university’s Information Technology Central Services (ITCS) department works hard to ensure that necessary information can be readily accessed. The University of Michigan is currently testing the ability of VeriSign IP Connect to bridge IP and cellular networks and provide access using a single device. “We want to determine the feasibility of allowing students and faculty to move between various networks that may or may not be owned by us,” says Pradip Patel, senior engineer for the university. “We want to find out if this is possible now, and then we’ll work with VeriSign to anticipate which advancements might be possible in the future.” Andrew Palms, director of communications systems for the university, says that the students, faculty, and staff at the university comprise a highly mobile population. “If we could provide telephone service to each of these three groups,” says Palms, “across privately owned devices and devices provided by the school, we could enable communication at a fixed cost, and remove some of the communication barriers between these parties.”

The University of Michigan began its testing using two Hewlett-Packard® iPAQ h6300 Pocket PCs, personal digital assistants (PDAs)/phones that provide both Wi-Fi and cellular connectivity. VeriSign installed a Session Initiation Protocol (SIP) client onto each handset, which allows them to register on the campus IP network. The IP network is hard-wired to a Nortel Networks® Meridian SL-100 private branch exchange (PBX), a carrier-grade system that supports 35,000 phone lines. The SL-100, in turn, connects out to the VeriSign network over a virtual private network (VPN) that is managed and monitored by VeriSign® Managed Security Services, which protect worldwide enterprises and critical US Government resources.

VeriSign IP Connect goes to work as soon as the iPAQs register their presence on the campus IP network. The user’s phone number is stored in the VeriSign® Network Routing Directory (NRD), an intelligent system that can interoperate with VeriSign’s Signaling System 7 (SS7) network, which, in turn, has connectivity with cellular networks and the Public Switched Telephone Network (PSTN) for wireline services. The NRD is designed for extremely fast lookup, high reliability, and maximum scalability; it runs on the same infrastructure by which VeriSign routes up to 15 billion Web and email addresses every day. When users roam outside of the Wi-Fi coverage area and the SIP client is not present in the NRD, IP Connect simply routes calls using a cellular carrier under a roaming agreement, and ensures that the call is charged to the same number.

Currently, the university has been able to successfully use the iPAQs to make and receive calls over IP and cellular networks, using the same number. In addition, the university can use the dual-mode phones to call anyone on campus using the university’s 5-digit dialing plan.

Patel says that the university would benefit from testing the converged IP/cellular network using other dual-mode handsets in addition to the iPAQs which, being handheld computers rather than strict dual-mode phones, are prohibitively costly for widespread adoption ($579). Though a number of Wi-Fi-enabled cell phones should soon be available, none were available at the time of testing.

Looking Ahead 
Should the service prove its viability, the University of Michigan is interested in testing the service in a variety of settings, such as hospitals, where cell phones are not allowed. Supported by VeriSign digital infrastructure, universities, service providers, and enterprises are gaining new opportunities from existing technologies.