Wi-Fi/Cellular at Crossroads

Businesses going mobile today face a daunting array of wireless access technologies, services and devices that are fairly complex to cobble together. To maximize network coverage, for example, most large organizations must work with several cellular network operators. They also often run their own private wireless LANs for faster, less expensive mobile campus connections.

Achieving broad mobile coverage could soon become less cumbersome, however, as LAN-speed Wi-Fi networks and cellular networks take their first early steps toward convergence.

Managing cellular wireless alone is a challenge that typically involves purchasing, provisioning, managing and securing a variety of wireless cards, devices and network service suppliers.

"When managing multiple vendor relationships and configurations, the cost rises exponentially and eats up time," says Tony Fuller, CIO at a large retailer. "And users adjusting to use different networks spend time concentrating on the device, not on the work at hand."

The convergence of Wi-Fi and mobile devices and networks -- which will eventually hand off signals to each other so users won't have to reauthenticate when crossing network boundaries - could help address these problems. Nascent industry endeavours to bridge these environments promise to extend the reach of wireless networks, reduce the number of client devices per user and streamline the lives of both IT and the mobile worker.

The IT community likes the sound of wireless convergence -- at least on paper. "We use both wireless [LAN] and cellular. Obviously, we'd love to have the two converge into a single wireless source," says Vern Butler, chief technology officer at CWCapital, a commercial loan company. "Handoffs between mobile networks would allow our lenders to continue conducting business independent of the network available and maximize the use of their time."

Paul Limon, IT manager for the Americas at heavy equipment manufacturer JCB, concurs. "Extending our [virtual LANs] out across multiple wireless networks would be a natural for us, particularly for our quality-control inspectors," he says. "Who wants to continually log on and log off?"

The required technology components are arriving piecemeal, however, so converged mobile nirvana isn't here just yet. As a first step, laptops and handheld devices are gaining embedded connections to both Wi-Fi and mobile WAN networks. This gives a device a higher probability of finding and connecting to a nearby wireless network, effectively extending the user's mobile coverage. Some converged service offerings are already available.

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Aggregating services

Network aggregation services from companies such as iPass and Fiberlink Communications represent an early move toward convergence. The wireless and wired network services they bundle and resell from carriers around the world are used with client devices that support connections to multiple networks.

The various services are accessible from a common client software interface provided by the aggregator, so users can access the best available network wherever they are. The aggregator maintains the multicarrier relationships and provides back-end security, billing and settlement services.

The mobile WAN component of these offerings isn't yet globally cohesive, however. "The wireless support of today's providers is not yet mature enough" to consider aggregators for worldwide mobile convergence, says Albert Hitchcock, CIO at Nortel Networks. The communications company supports 27,000 global users carrying mobile devices equipped with both Wi-Fi and cellular technology.

IPass and Fiberlink both support access to Wi-Fi hot spots around the world and resell Verizon Wireless' Evolution Data Optimized (EV-DO) services in the US. Outside the US, however, customers usually must buy mobile WAN services directly from individual providers. The aggregators' connection management client software will allow access to these networks, but managing the global mobile WAN carrier relationships is a key one-stop-shop benefit that isn't yet available internationally.

For seamless internetwork roaming once the desired network connections are in place, mobile client/server VPN software can be installed to let wandering users maintain sessions across network boundaries while retaining authentication credentials. Also, some hardware vendors, such as technology partners Motorola, Proxim Wireless and Avaya, are starting to offer premises equipment that handles Wi-Fi-to-cellular signal handoffs for voice calls. Carriers are also exploring services-based handoff alternatives.

Today, the mobile components needed for expanding coverage via roaming among multiple networks must be bought and deployed separately. Achieving smooth roaming among wireless networks with no break in a session requires IT to buy, install and manage multiple physical connections per device and deploy special client/server software to enable session persistence when roaming.

In addition, Wi-Fi-to-cellular handoff products and services leave IT departments speculating about the logistics of merging their networks with a carrier's in terms of service levels, troubleshooting and security.

"The subject of service-level agreements is fastidiously ignored by those who advocate mixed 802.11 and cellular solutions," says Doug Hill, an associate technical fellow and network chief architect at The Boeing Co. Carriers have approached Boeing about running a carrier-controlled mixed network where the carrier charges for voice-over-WLAN calls handed off to Boeing's internal Wi-Fi network at a lower rate than for the portion of a call moving over the cellular network.

But in a potential bridged Boeing-carrier infrastructure, neither party could monitor or troubleshoot across the public/private network boundary without sharing management information with the other. Not sharing the information with the carrier could degrade service quality, but doing so could introduce security concerns, Hill says.

This conundrum is one reason why Nortel, at least in the short term, will probably use premises-based equipment for such handoffs. The company is running trials in the US of Wi-Fi-to-cellular handoffs with carriers, testing the capability as both a premises-based and a carrier services function, Hitchcock says.

Another reason to house and manage the handoff equipment internally for now, Hitchcock says, is that "there's no single, global carrier that can serve our 70-country footprint".

Roger Entner, vice president of wireless telecom at researcher Ovum, said, "Your carrier can loan you another [modem] card if you [travel internationally]. Your other option is to rely on global Wi-Fi hot spots."

Roaming issues are why United Parcel Service now does business directly with the world's five largest network operators. UPS drivers use the company's self-developed, laptop-based Delivery Information Acquisition Device (DIAD) to frequently transmit delivery status information to the corporate mainframe.

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The latest DIAD version, introduced last year and in use by 40,000 drivers, supports dual mobile WAN connections matched to the services with the best coverage in the post codes of a given driver's territory, says John Killeen, director of global network systems at the worldwide delivery services company.

"The previous DIAD generation ran primarily on the Cingular network," Killeen says. "We found that 81 percent of our network problems related to roaming onto a Cingular partner's network. So now we have separate, direct contracts in place with all the primary carriers."

For now, UPS's roaming needs are confined to the mobile WAN. Sales-force personnel use EV-DO services and laptops; the company's warehouse-based personnel use Bluetooth finger-scanners that transmit package information to the company's 2000-site Wi-Fi LAN and don't require cellular connectivity. The company has made a conscious decision not to include voice in the DIADs so as not to "interrupt the driver's day", Killeen adds.

Anthony Marano, a fruits and vegetables wholesaler that turns much of its business around in a day's time, relies on voice-centric cellular/Wi-Fi convergence to survive.

"Some 80 percent of our business volume involves customers physically delivering, e-mailing or faxing us an order for produce that's needed within 48 hours," says Chris Nowak, IT director. As a real-time business, the company can't afford the delays associated with extensive voice mails and callbacks and desktop-bound e-mail, he says.

The company treats the nascent Enterprise Seamless Mobility system from Motorola, Proxim and Avaya as its production telephone network, even though it is technically still a pilot project. The year-old setup facilitates phone-call handoffs between the company's Wi-Fi network and the GSM cellular network from Cingular Wireless, allowing buyers and sellers to remain in continuous communication with customers and vendors.

The premises-based equipment integrates Anthony Marano's Avaya IP PABX with its wireless LAN, the cellular network and a dual-mode handset -- the Motorola CN620 -- that "speaks" both 802.11a (5-GHz) Wi-Fi and quadband GSM cellular.

Users can have a single phone number that reaches them on the campus Wi-Fi network, which extends across a space of 27,870 square metres, or on the cellular network when they are out of the office -- provided that the number called is the IP PABX number, Nowak says. The system extends phone calls, four-digit PABX dialling and phone transfers to the Cingular network; employees use browser-based Outlook Web Access on the CN620 for e-mail, he says.

John DeFeo, corporate vice president of enterprise products at Motorola, says this setup is in a half-dozen trials around the world, but Motorola has decided not to deploy the CN620 as a commercial product. Rather, the company intends to enhance the handset and related system components with unified mailboxes, presence capabilities, enterprise-class instant messaging and possibly additional Wi-Fi radio support. The next-generation system is scheduled to ship in the first half of next year, according to a company spokeswoman.

While a range of converged devices are already emerging, some IT executives would rather see cellular service stabilized and coverage enhanced before getting still more sexy handset choices.

Dale Frantz, CIO at Auto Warehousing, says, "The bane of my existence is that people love Treo [handheld] devices, because the push technology for 'always-on' e-mail access is unreliable. The network drops sessions and user credentials between cell towers and creates a significant support burden.

"It seems there haven't been many performance gains in cellular communications," Frantz adds. "I believe that stabilizing the network services is at least as important as delivering the next device that plays [your favourite song]."

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Waiting for WiMax

Tony Fuller, CIO at a retailer with 3000 shops and 7000 trucks, is holding out for a single, ubiquitous mobile network technology. "It is very difficult to find a consistent service across the entire country," says CIO Tony Fuller. This is problematic managers responsible for multiple stores can traverse three states in the same day, he says.

Fuller thinks mobile WiMax might solve the problem. The technology promises about 1.6Mbit/sec. per subscriber, outstripping the bandwidth of today's broadband cellular networks.

Sprint Nextel is actively testing WiMax, and Intel, a key developer of the technology, says it is also in trials with other carriers. Intel plans to embed mobile WiMax connections directly into laptop motherboards next year.

"We're looking for one technology rather than one provider," Fuller says. "If the user has to figure out what kind of connectivity is available, that's awkward. If it can be transparent, that's worth its weight in gold."

With the advent of mobile WiMax, Fuller hopes his company will need to train people on only one technology and use just one connection in each device. "If you add up the number of people I have to cover, times the cost of multiple network connections each, that gets [expensive]," he says.

Such benefits aren't guaranteed, however, considering that today's competing cellular service offerings, although based on the same technology, don't use compatible connection gear.

Dual-mode devices ready to roll

Laptops, which are already shipping with embedded Wi-Fi connections, are now gaining integrated mobile WAN connections, too. Lenovo Group's Z-, T- and X-Series ThinkPads, for example, now ship with both embedded Wi-Fi and 400Kbit to 700Kbit/sec EV-DO connections. Dell began directly integrating Cingular Wireless HSDPA/UMTS connections into its Latitude line of notebooks in late March; the connections are backward compatible with EDGE and GPRS networks throughout the world. Dell has also said it will integrate Verizon Wireless' EV-DO connectivity into its Inspiron and Latitude lines this year.

Dual-mode wireless handheld devices are also emerging. Users can choose from several dual-mode mobile devices for running data over either a mobile WAN or a Wi-Fi LAN, including units from Hewlett-Packard, Intermec Technologies, Motorola and Psion Teklogix. Research In Motion offers a BlackBerry that also supports voice/data over cellular or over an 802.11b Wi-Fi network, but not both.

"It's crazy that you can't combine Wi-Fi and GSM in the BlackBerry," says Paul Limon, IT manager for the Americas at JCB. "We're all road warriors, and we all want [these services] on a single device for a single price and consistent and reliable speeds." When it announced its Wi-Fi- capable BlackBerry last year, RIM said that it would eventually support both cellular and Wi-Fi in a single device, but the company hasn't yet announced a delivery date.

Some manufacturers do offer dual-mode options for voice and data. Symbol Technologies offers a high-end MC70 starting at $US2000. The rugged, multifunction device supports Wi-Fi and cellular data and voice, scanning, push-to-talk and other capabilities.

In Japan, the NEC N900iL dual-mode handset is available for use with NTT DoCoMo's third-generation service. Other devices enabling voice and data over both Wi-Fi and mobile WAN services are expected from Nokia and G-Tek Electronics this year.