Various efforts to standardize seamless roaming remain nascent, but several companies are trying to ensure that upcoming Wi-Fi/cellular services are able to tie in to both hot spots and corporate PBXes.
While Cisco Systems Inc. has no plans to build its own dual-mode handsets, the San Jose, Calif., company is working with several wireless phone makers to ensure that the phones work with Ciscos IP PBX systems, with eventual plans to launch an official compatibility licensing program. "There is a lot of cross-breeding going on," Larry Lang, general manager and vice president for the mobile wireless group at Cisco, said at CTIA Wireless last week.
Nortel Networks Ltd. is launching similar efforts with its own enterprise IP telephony systems, said officials at the Richardson, Texas, company.
Phone makers are doing their part, too. Research In Motion Ltd. plans to make its new voice-over-Wi-Fi BlackBerry work with corporate IP servers from several companies, including Cisco and Nortel, said RIM officials in Waterloo, Ontario. Nokia Corp. plans to add Wi-Fi to most of its enterprise-level phones, said officials at the Espoo, Finland, company. Motorola Inc., of Schaumburg, Ill., is readying dual-mode phones as well.
"I would love a handset that would use WLAN [wireless LAN] internally but also was my cell phone," said Jorge Abellas-Martin, CIO of Boston-based advertising corporation Arnold Worldwide and an eWEEK Corporate Partner. "So far, though, it seems that only the PDA phones are big enough to support such a multiplicity of radios—wireless LAN, cellular and Bluetooth. And I am skeptical that it will be easy to integrate across multiple vendors."
There are WAN/WLAN protocols in the works. The UMA (Unlicensed Mobile Access) specification focuses on roaming between GSM/GPRS (Global System for Mobile Communications/General Packet Radio Service) networks and WLANs. It includes among its participants such major players as Cingular Wireless and Nortel, but it isnt ideal for enterprises because it doesnt support SIP (Session Initiation Protocol).
A solution that uses IMS (IP Multimedia Subsystem), from the Third Generation Partnership Project, is an alternative roaming option and supports SIP for tying in to a corporate IP PBX. Still, an official industry standard for dual-mode roaming has yet to be chosen.
Cisco officials said they have been eyeing both the UMA and IMS options. "Were in the position where we have the luxury of hedging our bets," Lang said.
Carriers, however, are cautious. "Right now, the technology is pretty proprietary," said Jeff Bradley, vice president of business data services at Cingular Wireless, in Redmond, Wash. "We dont want to burn our customers by taking them down a path too soon."
That said, Cingular is in trials with a Fortune 500 company, testing a device that uses Cingulars GSM/GPRS network when it is outside the office and switches to Wi-Fi on the PBX on the inside, Bradley said.
On the CDMA (Code Division Multiple Access) front, Nortel last week announced a system designed to bridge CDMA wireless networks and WLANs. Due for trials later this year, the Converged Mobility system allows for managed subscriber billing so customers can receive one bill for both Wi-Fi and WAN.
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