Municipalities Starting to MeshBy Eric Nee | Posted 03-22-2005
Municipal governments aren't generally known for being on the cutting edge of technology. Just the opposite, in fact. Many city offices still look much as they did in the 1970s, or earlier, with rows of bulging file cabinets squeezed against the back wall, and flickering green screens sitting atop clerks' desks.
There is one area, however, where municipalities are breaking new technology groundbroadband wireless networks. Cities as diverse as Philadelphia, Las Vegas and Garland, Texas, are all experimenting with mesh, a new way of building wireless networks. "We've got 10 to 15 good-sized cities sitting on the fence waiting to see what happens in Vegas," said Mitchell Gonzalez, president and CEO of Cheetah Wireless Technologies Inc., a Las Vegas firm that has been hired by the Las Vegas Traffic Engineering Department to build and run a trial network smack in the middle of Sin City.
The reason that so many cities are entranced with mesh networks is their potential to leapfrog conventional WiFi, 3G cellular and even WiMax networks, by offering more complete coverage, faster speeds, greater reliability and easier deployment. Better yet, mesh networks promise to do all this for less money than many existing wireless networks. At least that's what proponents argue. Like any hot new technology, however, there is a certain amount of hype and exaggeration that has to be discounted. (More on that later.)
If mesh lives up to expectations, cities will be able to improve services, increase municipal employee productivity, provide residents with better and less expensive Internet access and create a more vibrant business climate. Municipal mesh networks aren't going to replace the broadband networks that snake through downtown high-rises, but they can provide broadband connections for small and medium-size businesses that can't otherwise afford them, or are located in areas of the city where broadband is not available. And just as constructing roads, sewers and electricity grids helped some cities leapfrog others in the early years of the Industrial Age, building a broadband infrastructure throughout the city limits will help cities compete in the Information Age.
Here's why wireless mesh technology is so entrancing: In a conventional wireless network, each client device, whether it's a PDA or a laptop, communicates directly with a cell tower or WiFi base station. For the network to function, the cell tower has to be up and running, which isn't always the case, and more important, the laptop has to be within range to send and receive signals. If the laptop is out of range, if the signal is weak, or if the cell tower is down, you're out of luck. It's a bit like the traditional mainframe computer model, in which terminals can communicate with the mainframe, but not with one another.
A mesh network is more like the Internet. All the devices that make up a mesh network are peers of one another, able to send and receive WiFi, WiMax, or other wireless signals with any other device within range. Signals are sent from one device to the next until they reach an Internet access point (the equivalent of the cell tower, it's a device that sends and receives signals and is hardwired to the Internet). Like the Internet, routing tables in each device help determine the optimum path for every signal.
One of the beauties of a mesh network is that it is redundant. If one node or device stops working, or is bogged down with too much traffic, then data is simply routed around it. This makes the mesh network more efficient and reliable than a conventional one. And if more bandwidth is needed, it is easy to boost performance by dropping in new nodes when and where they are required.
Dianah Neff, CIO of the city of Philadelphia, plans to blanket the city with 3,000 to 4,000 network nodes, which will cover each of the city's 135 square miles with a WiFi signal. These nodes in turn will send signals to Internet access points sprinkled throughout the city that are either hardwired or use WiMax to connect to the Internet. The nodes will provide uniform coverage along all of the streets, parks and other open spaces of the city, at an average data rate of one megabit per second upstream and downstream. The wireless signals may bleed over into some homes, businesses and office buildings, but not by design. "We are building the basic infrastructure," Neff says. "It will be up to others to provide services into the home or business." Philadelphia doesn't want to be in the business of offering Internet access to the public. Instead, the city is devising plans to contract with private organizations that would use the mesh infrastructure and extend inexpensive Internet access to homes and businesses.
And mesh is inexpensive to install. It costs about $20 per household to install a mesh network in a neighborhood, compared to $700 to $1,000 per household to bring in a wired broadband network such as DSL, according to Neff. Those savings can be passed on to subscribers, which is crucial for a city such as Philadelphia, where 23 percent of its 1.5 million residents are below the poverty line, and 42 percent of city households still lack Internet access of any kind. "The impetus for doing this was to meet the mayor's goal of overcoming the digital divide," Neff says.
The cost of building the city's portion of the wireless infrastructure will total only $10 million, Neff estimates. There are no large cell towers to construct, and the network nodes are small boxes that use very little electrical power, and can be attached to city-owned light poles. "Our crews installed 37 nodes in two days," Neff says. And much of the backend infrastructure that the Internet access points attach to, such as fiber optic cable, is already installed. Philadelphia's mesh network will operate in the same unlicensed spectrum as WiFi, allowing anyone with an 802.11 card to pick up the signal, and, for a price, connect to the Internet.
Does this all sound too good to be true? It just might be. "It reminds me a bit of 3G, or Bluetooth," says Philip Marshall, director of wireless and mobile technologies at the Yankee Group. "Mesh has its place, but the market is assuming it can do more than it can. Some of the initial deployments are exaggerating its potential."
One problem early adopters are running into has to do with the very thing that makes mesh so attractive: the ability of every device on the network to pass on signals, what is called "hopping" in mesh parlance. Some early proponents said signals could be passed from one device to the next almost without limit. It turns out that each time the signal hops, some of the bandwidth drops away. While there may be ways of mitigating this problem, it is better to have one, two, or at most three hops from the client device to the Internet access point.
Garland, Texas, a Dallas suburb with 221,000 residents spread over 57 square miles, ran into this problem when it began building its mesh network, which was designed to provide high-speed communications for police, fire and medical emergency teams. "Right now we probably have more hops than we want," says Darrell McClanahan, telecommunications director for the city of Garland. "We want to deploy more Internet access points in the network to keep it down to two, maybe three hops maximum." But adding more Internet access points increases the cost of the network.
Still, mesh is so promising that Motorola Inc. recently bought one of the leading suppliers of mesh technology, MeshNetworks Inc., and announced plans to incorporate mesh in its wireless products for a variety of markets. Don't be surprised to see an explosion of interest in mesh over the next year or two as these initial forays give way to broad rollouts around the country.
Eric Nee, a longtime observer of Silicon Valley, has served in a variety of editorial positions at Forbes, Fortune and Upside magazines. His next column will appear in May.