WiMAX: your next WAN?

It's all the rage for empowering mobile workers, but David Braue wonders whether WiMAX could also displace ADSL as the corporate WAN technology of choice.

It may not seem like world-beating news, but a quiet trial of WiMAX (worldwide interoperability for microwave access) wireless broadband technology at this year's Australian Grand Prix has opened up an entirely new market for the emerging technology.

In a project supported by Intel, Unwired and equipment provider Airspan Networks, doctors from Melbourne's The Alfred hospital, who relocate to Albert Park every year to treat sick and injured drivers and staff during the four-day event, used WiMAX to connect their trackside LAN to diagnostic systems back at The Alfred, several kilometres away.

That transmission, believed to be Australia's first ever use of WiMAX over licensed spectrum, used the high bandwidth of WiMAX to transmit large radiographic image files from the onside PACS system to specialists at The Alfred. These files are so large that in previous years they were burned onto CD and driven back to The Alfred for analysis by in-house radiologists - a 20-minute trip that was significantly slowing delivery of test results for patients at the satellite facility.

Success in extending The Alfred's LAN into the field paints a rosy future for WiMAX, which has been heavily hyped since its inception and looks to finally become a commercial reality with trials planned later this year and services by the beginning of 2007.

Interest in the technology has particularly taken off since the recent ratification of the IEEE 802.16e Mobile WiMAX standard, which allows a device to connect to a WiMAX base station and stay connected even while the user is moving - an essential requirement for supporting mobile workers.

The previous 802.16-2004 interim standard, also known as fixed WiMAX, only allowed connectivity from fixed locations but is rapidly losing mindshare as the more broadly appealing 802.16e standard catches on. "From a commercial sense, [Mobile WiMAX] is where we are focused," says Rob Inshaw, Asia-Pacific director of WiMAX with telecommunications gear giant Nortel Networks. "Scale and volume will be with WiMAX over time, and we are putting all our resources into building that WiMAX ecosystem."

Ready for business?

With cell coverage measured in the tens of kilometres and data speeds of up to around 75 Mbps, both flavours of WiMAX combine the flexibility of wireless LANs with the speed of fixed networks. And while many operators are now targeting low-hanging fruit by pitching always-on wireless broadband to consumers and mobile workers, the technology's coming ubiquity and strong performance begs a different question for business customers: could WiMAX be the future of the WAN?

Some wireless operators certainly think so. One company set to jump onto the WiMAX bandwagon is BigAir Group, which has built a fast-growing business both as a reseller of iBurst roaming wireless broadband services and an integrator of high-performance microwave WAN technologies running at up to 100 Mbps.

BigAir plans to begin Mobile WiMAX trials later this year and offer commercial services early in 2007. And while individual mobile users form a major part of the company's plans, CEO Jason Ashton believes WiMAX could also be an ADSL killer because it offers easier installation and the faster upload speeds necessary for two-way LAN-to-LAN communications.

"I think it will be a very strong alternative to fibre," Ashton says, "and it will kill ADSL because ADSL just cannot deliver business' requirements for uploading. [The current cap of] 1 Mbps is barely broadband in today's world, whereas we can today deliver up to 25 Mbps using pre-WiMAX solutions and can customise solutions up to 100 Mbps. On the wireless side, there are no artificial limits placed on uploads versus downloads."

Other, symmetric flavours of xDSL offer faster bidirectional services, but their limited availability and high cost have made widely available ADSL the remote office connection technology of choice despite its upload restrictions. And even recent moves by broadband provider Internode to introduce Annex M technology - which increases upload speeds over ADSL2+ links to 2.5 Mbps - will still fall far short of WiMAX speeds.

Although lopsided asymmetric ADSL services work well for download-focused web use, corporate networks require high-speed transmission in both directions. In high-bandwidth applications, those requirements are well serviced by fibre-based metropolitan area networks (MANs) capable of pushing data between offices at 10, 100 or 1000 Mbps. However, lower cost and wider reach could potentially give WiMAX technology an edge over both ADSL and fibre MANs in situations where businesses - particularly cost-sensitive smaller companies - need to provide seamless LAN connectivity between offices.

That wireless networks can provide effective WAN services at all, is being proven by converts such as Jetstar Airways, which is using Telstra's low-speed EV-DO service to deliver applications to its new airport check-in desks. Those applications will be hosted at the company's data centre and delivered using low-bandwidth Citrix Metaframe technology, which runs happily over the bandwidth that EV-DO provides.

"We've found that we can still deliver a 97.5% availability service with a primary and secondary access method," says CIO Stephen Tame. "You're not going to get 1 Mbps and 2 Mbps broadband connections [over EV-DO] but you will get 100 Kbps, and I only need 40 Kbps to run a thin-client. And if we have any problems, we can still use dial-up."

This set-up is both cutting the cost of terminal management and allowing Jetstar more flexibility in terminal service such as installing temporary EV-DO connected terminals during times of peak demand. By offering speeds dozens of times faster, other companies could use WiMAX to take this paradigm a significant step further. Fast bidirectional data transfers, combined with the availability of a fast and secure wireless connection anywhere, would allow mobile staff direct access to the corporate LAN at speeds that improve delivery of many services.

Such connectivity could pave the way to a whole range of new WAN-type solutions. Following on from the success of the Grand Prix trial, Intel for one is considering how WiMAX might be used to quickly wire emergency sites and empower ambulance and other emergency staff in the field. High-speed WiMAX could, for example, allow ambulance officers to use videoconferencing to give waiting emergency specialists a high-quality view of the patient they are transporting.

With the right creative minds at work, availability of high-speed broadband anywhere can improve all kinds of business processes. For example, support salespeople could quickly download multimedia-rich product demonstrations while in the field. Rapid data replication between the home office and WiMAX-enabled notebooks could resolve remote data backup problems.

Multi-participant videoconferencing could be conducted anywhere, any time at digital television quality. And set-up of an IP PABX at a temporary site could quickly provide phone lines just about anywhere - an approach that Cisco Systems used with a satellite-connected IP telephony solution provided during the Hurricane Katrina clean-up effort.

Control issues

The idea of WiMAX as an enabler for better WAN connections has slowly gained currency among some analysts. Gartner, for one, agrees that the technology could give ADSL a run for its money, although increasing noise from competing solutions such as 3G networks' coming 1 Mbps HSDPA technology - which will enjoy a strong coverage footprint thanks to carriers' ongoing 3G buildout - could cloud the picture for customers.

Tony Tu, industry analyst with Frost & Sullivan, is more cautious in his expectations for the technology. "We see WiMAX as an alternative for last-mile access, but don't see it as a viable replacement [on the WAN]," Tu says. "The reality is that people are used to having 99.999% or 99.9999% availability on their WANs, but WiMAX will only be 99.99% or so.

"Over the period of a year, that can be quite a long time," he continues. "Looking at issues such as quality of service, security, availability, interference, redundancy, resilience, capacity and bandwidth - especially when you compare WiMAX with conventional WANs using copper and fibre - we see those technologies outperforming WiMAX."

Rather, Tu believes WiMAX will be most popular as a replacement for existing fixed microwave links, which are widely used to link university campuses and other distant sites but remain relatively expensive. Another possible growth market for WiMAX-based WANs, he adds, would be as a backup for other fixed or wireless links, or as a method for quickly providing short-run line-of-sight links between buildings.

One issue that is sure to shape corporate take-up of WiMAX is the use of licensed and unlicensed spectrum. Unwired Australia, which owns the licence to most of Australia's radio spectrum in the frequencies where WiMAX operates, will effectively have its own clear path to roll out WiMAX services. Because they operate over a tightly controlled airspace, such third-party services should be reliable and interference-free - which should allow Unwired and its resellers to offer service level guarantees.

Many companies, however, will want to introduce their own WiMAX equipment to set up WAN links that connect directly into their own networks. This equipment will run in more congested, unlicensed radiofrequency spectrum, where potential interference and overcrowding could make for an unpredictable performance profile.

"The challenge for any radio is reliability," says Adam Radford, consulting systems engineer with Cisco Systems. With weather, interference and general environmental change all able to attenuate wireless signals, "there is more scope for things to go wrong in the wireless space than the fixed space," he explains.

The design of WiMAX, which has been built to operate on the assumption that it is working in uncluttered licensed radiofrequency spectra, doesn't improve the situation.

"It assumes that it has full control of that particular spectrum at that point in time," Radford explains, citing shortcomings with "the way it deals with collision, and with other people using the spectrum at the same time. Wi-Fi has algorithms that let it back off gracefully, but WiMAX assumes it will have sole use of the spectrum and doesn't back off."

Still others argue that the truth lies somewhere between the two extremes. Assuming that WiMAX may have trouble in areas such as in-building penetration, companies such as Nortel Networks are pressing the case for a combined solution that provides seamless roaming between in-building Wi-Fi and out-of-building WiMAX services for WANs and mobile employees.

However, if it's introduced, the speed and broad coverage of WiMAX is likely to prompt corporate investment in the technology for far more applications than simply connecting mobile employees in the field. Using it as a WAN alternative will make sense to many companies, but there's no need to be fanatical about it; ultimately, the key is to think of WiMAX as one of numerous viable options for site-to-site connectivity.

"The wireless space is complementary rather than predatory," says Radford. "There's not normally one wireless solution that provides everything you need at the price point you need, so it's about looking at your business requirements and finding the one that suits you best at that particular point in time."

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