Dual-mode devices that merge cellular and Wi-Fi networks are on the way. What has to happen to make them work for your business?
Today, mobile business users navigate a patchwork of wireless networks. Most connections must be set up, torn down and reinitiated when users cross Wi-Fi and cellular network boundaries.
Consumer services are expected to come first
“We’ve dreamt about this scenario for several years,” says Brian Chernish, network operations director at Western States Insurance Agency in Missoula, Mont. “It would increase employees’ availability and their ability to conduct business wherever they are.”
Pieces of this converged landscape, such as dual-mode handsets, the simultaneous ringing of multiple phones and unified voice mailboxes, have surfaced. In the data world, client/server products called mobile s allow workers to roam across different wireless network types with no breaks, so long as the client device sports connections to multiple networks. But to date, voice isn’t part of the mobile VPN picture.
“We’re still a couple years away from dual-mode voice being seamless enough to be used in the enterprise,” Chernish says. It looks as if companies will have ample time to prepare for this type of convergence.
One reason is that dual-mode phones have gained limited support from mobile network operators, who worry about cannibalizing their cellular voice revenues. “Carriers are still figuring out how to accommodate enterprises’ requests for VoIP over Wi-Fi in a way that makes them money,” says Charles Golvin, principal analyst at Forrester Research.
Second, customer premises equipment (CPE) that handles the back-end signal handoff, which would allow enterprises to build and manage the converged network themselves, is in its infancy. Motorola, with partners Avaya and Proxim Wireless, as well as start-up Divitas Networks, are among the companies with such equipment in pilots.
Finally, many organizations haven’t optimized their wireless LANs for voice coverage, which requires Wi-Fi propagation to all corners of the enterprise. Most initially installed Wi-Fi for data transmission in mainstream locations, where users are likely to pause to send an e-mail or download a file. On a mobile phone call, though, users might wander anywhere while expecting their conversations to remain live with consistent quality.
“Our Wi-Fi network is built for conference rooms and guests, not blanket coverage,” acknowledges the global network architect of a worldwide consumer products company who asked not to be identified. “We’d need to pop $400,000 to $500,000 [in infrastructure] to use Wi-Fi instead of cellular for voice” just within the company’s U.S. headquarters, he says.
Carrier and manufacturer activity
No U.S. carrier has announced a dual-mode business service yet, so it’s early to speculate on potential cost savings. However, Cingular Wireless’ OfficeReach service, which combines customer PBXs and cellular services to help companies lower their internal cell phone charges, could serve as a potential billing model.
If a call is made from within an enterprise-defined zone, it is billed at OfficeReach rates, which are lower than traditional cellular rates: about 2 cents per minute for in-zone cellular-to-landline calls, says Rana Khasnavis, Cingular executive director for business voice products. Cellular calls between corporate PBXs cost “fractions of a penny,” he says.
Cingular says it expects to sell dual-mode phones in 2007, when its IP Multimedia Subsystem (IMS) infrastructure is in place. IMS is a set of standards, backed by the Third Generation Partnership Project (3GPP) worldwide mobile standards body, for telecom infrastructures that bridge the Internet and cellular environments. “We’re trialing dual-mode services, and we are looking at both businesses and consumers,” says company spokesman Ritch Blasi.
Verizon Wireless and Sprint Nextel say they haven’t committed to offering dual-mode service and are studying technology, products, and the issues associated with Wi-Fi’s unlicensed spectrum.
Dual-mode phones are shipping from HP, HTC, LG, Motorola and Nokia. Many support data connections to cellular and Wi-Fi, as well as voice over cellular, but without inherent voice-over-Wi-Fi (Vo-Fi) capabilities.
However, the dual-network voice capabilities are available on handsets from HP, Motorola, NEC and Nokia from mobile network operators in countries outside the United States. At press time, others were poised to ship in the United States from Nokia, Samsung and UTStarcom (see graphic). ABI Research expects shipments of dual-mode phones to exceed 300 million by 2011.
Some dual-mode phones are programmable, which means users could download an IP telephony client on them to make voice calls over both networks. However, there are two problems with this: One is that the Wi-Fi and cellular sessions remain separate, without benefit of network handoff and unified messaging. The other is that using a VoIP software client across a cellular data service is an infraction of most U.S. cellular carriers’ standard terms and conditions.
Skype, however, has reportedly been working with Fujitsu-Siemens, Motorola and Nokia on developing dual-mode handsets with its IP telephony client software built in. Presumably, a mobile network operator rebranding and selling these handsets would permit the VoIP service over its network.
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For now, enterprises can get limited wireless convergence capabilities in integrated communications servers. They can have multiple phones ring simultaneously when a single PBX number is dialed, for example, and check a single unified cellular-Wi-Fi voice-mail box for messages. These capabilities are available from companies such as Avaya (the EC500), Cisco (MobileConnect) and Ascendent (Voice Mobility Suite). Ascendent was purchased earlier this year by Research In Motion.
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How to prep for dual-mode device deployment
* Build out your Wi-Fi network for all-over voice coverage if you haven’t already. This will require conducting a voice-centric, radio-frequency site survey.
* Ask carriers and handset suppliers about the battery life of dual-mode phones to ensure that the user experience doesn’t degrade.
* Global companies often use tri- or quad-band cellular phones. If you’re one of them, find out if you will have to give up any cellular radios and services in a dual-mode device to gain Wi-Fi.
* Investigate whether you’ll be able to procure the dual-mode devices you need from the carriers you prefer for best coverage.
* Work with your mobile network operator and CPE vendor to determine cross-network security and troubleshooting schemes.
End-to-end issues
A key issue to iron out with a service provider or CPE maker is getting a consistent security scheme that will work transparently between the Wi-Fi and cellular networks.
“Users will be moving between VoIP on the Wi-Fi network and circuit-switching on the cellular network. There are different forms of security used with each, and, frankly, I haven’t seen anyone address this yet,” says Bob Egan, research director in the emerging technologies group of TowerGroup.
Rosanne Carey, Trinity Health’s director of telecommunications in Farmington Hills, Mich., is using SpectraLink’s Vo-Fi system and is investigating dual-mode voice options. She expressed concern over the security issue. “We will perform a risk assessment to determine the risk of handing off a call to a public network,” she says. “Our security policies would have to be modified to support” the results.
IT managers should note that early Wi-Fi-to-cellular handoff equipment must be initiated by the business (PBX) phone number for seamless handoff to take place in either direction. In other words, calls must be placed from or received by the direct-inward-dial number, not the cellular number.
“Fixing this issue could be a great value-add from a carrier,” suggests Chris Nowak, IT director at Anthony Marano, a fresh-produce distributor in Chicago. The company has been piloting a CPE-based Wi-Fi-cellular phone system from Motorola, Proxim Wireless and Avaya for the past two years. “We’d pay the $2 or $4 [per line, per month] for that capability,” Nowak says.
Another issue is managing mixed private Wi-Fi and public cellular networks. “There’s no troubleshooting support model yet,” says Joe Fearday, telecommunications manager at Trinity Health. “There is a compelling business case for dual mode in getting our clinicians to a single device and avoiding a tool belt of communications equipment. But we’d need packet analysis of the handoff, because when a doctor loses a call and wants to know why, we’ll be put in the position to figure it out.”
Other IT executives are also reluctant to share management information about private networks with their mobile carrier to facilitate end-to-end troubleshooting.
David Wirth, manager of technical operations at Princeton University, says: “We’d rather not have a third-party provider in our network and wiring closets for security reasons.” Princeton is running an internal pilot of Vo-Fi using the Nortel MCS 5100 Multimedia Communications Server with wireless IP telephony handsets.
Wirth says that he’ll require cooperation from his cell phone providers for dual-mode to be a success. “Cell signals come to campus and must turn into Wi-Fi signals. If the carriers don’t cooperate, it won’t work,” he says.
Wexler, an independent editor and writer in Silicon Valley, is author of Network World‘s “Wireless in the Enterprise” newsletter. She can be reached at joanie@jwexler.com.
