CASTING A WIDER NET
Forget hot spots. Mesh technology brings fast and cheap wireless internet access to entire cities.
By John Edwards

Marion, information-services director for the Silicon Valley enclave of Milpitas, California, is the man in charge of an intriguing municipal project. The plan: to bring seamless wireless access to the city's mobile public workers wherever they happen to be in the town. Milpitas's new wireless infrastructure, known as a mesh network, is designed to give police officers, firefighters, and building inspectors, among others, access to crucial information at data speeds ranging up to five megabytes per second. The city is just one of a number of municipalities and businesses that are embracing mesh networks.

The interest is understandable. While both traditional wireless local area networks (WLANs) and mesh nets have limited range, mesh technology can be easily and cost-effectively expanded to cover a few thousand square feet or dozens of square miles. Unlike conventional radio and mobile phone-based data-communications systems, mesh nets generally don't have dead zones. They also process large chunks of data handily. The same cannot be said of cell-phone access to the web.

Mesh networks are also relatively cheap to roll out. They simplify network deployment by eliminating the need to install access points with direct cable connections to the internet. (With a mesh, all access-point backhaul traffic is sent over the air to a central station.) By getting rid of cables, companies can cheaply place internet access points in hard-to-reach places. Craig J Mathias, a principal at Farpoint Group, a US technology-research firm, estimates that a typical indoor mesh can cost up to 25 percent less than an equivalent conventional WLAN. With an outdoor mesh, savings can reach almost 90 percent.

For Milpitas, the real value, says Marion, is that it's the only technology currently out there that provides high-speed data traffic across a whole municipality. While the Milpitas project does violate the golden rule of technology purchasing (never buy really new gizmos), Marion says he could not wait for an ideal wide area networking solution to come to market. The city's existing Cellular Digital Packet Data system, running at a top speed of 19.2K bits per second, was simply too pokey to support the transmission of photos, maps, floor plans, and other large graphics files.

The Milpitas mesh, supplied by Tropos Networks, covers about five square miles and uses 32 access points. It connects the city's 30 police cars to the internet, allowing cops to access data on touch-screen computers mounted on dashboards and in glove compartments. The city also plans to connect its traffic cameras to the network, allowing firefighters and other first responders to view and evaluate an accident scene as they race toward the location.

Despite the obvious benefits, the technology is far from perfect. Makers, including Tropos, MeshNetworks, Firetide, and BelAir Networks, continue to roll out different and usually incompatible products, making it difficult for potential purchasers. So, too, does the notoriously high mortality rate of wireless start-ups. Early adopters of meshes could wind up stuck with networks that can't be expanded or upgraded or even serviced. Latency, too, could be a problem. As more users log on and more data is relayed between access points response times can slow. Since a mesh must carry both service and backhaul, bandwidth can vanish.

Still, the networks' vast potential outstrips its drawbacks. Experts believe mesh could dramatically alter inventory management and logistics. In Portsmouth, England, for example, city bus stops are linked to a US$6 million network supplied by MeshNetworks. Anyone at any bus stop in Portsmouth can walk up to a display and find the exact location of the next bus. Ken Dulaney, a mobile-computing analyst for technology-research firm Gartner, believes the networks are well suited for businesses with large outdoor operations. Ports and railroad yards top his list. "They are places where you have to cover a lot of area and you can't run wire," says Dulaney.

Enterprises can also blanket large indoor areas, such as office buildings, convention centers, sports arenas, warehouses, and factory floors. At the Computer History Museum in California in the US, a mesh supplied by Firetide provides Internet coverage throughout much of the institution's 120,000-square-foot building.

John Edwards is a freelance writer based in Arizona in the US.eir due diligence.