Mesh Gathers Momentum

An unconventional way of building wireless infrastructure, one in which routing is distributed and networks "grow" organically, appears to be gaining ground. Called "wireless mesh networking,” the technology holds out the promise of delivering low-cost broadband Internet access in places where conventional alternatives, such as laying fiber, would be prohibitively expensive.

Wireless Big Daddy Nokia Corp. recently lent the concept credibility when it announced that more than 50 customers have bought its RoofTop Wireless Routing mesh networking product, which is intended to enable service providers to deliver broadband services in areas where they can’t lay down copper wire.

The basic idea behind this kind of mesh networking is a system that uses a series of wireless gateways, or nodes, that pass data and share bandwidth among them rather than sending and receiving data from a central point. Mesh networking may be considered a team sport, with players passing the data “ball” up and down the field -- as opposed to the golf-like cable model, where a solitary player has to hit the ball into many different holes.

The mesh approach has a number of attractions -- one of them being that the available bandwidth increases with the number of nodes in the network. A downside might be that it’s tough to predict how many hops traffic will have to take until it reaches fiber or reaches its destination. That implies variations in network delays that might create quality-of-service (QOS) problems with some types of traffic, such as voice and video.

There are various ways of implementing wireless mesh networks -- using dedicated nodes or separate devices that can also function as nodes -- but the principle is the same.

This kind of networking is likely to initially appeal to service providers looking to meet the insatiable demand for broadband Internet access in areas that they can’t (or can’t afford to) install cable.

Certainly this is what Nokia is banking on; in September 1999 it bought Californian startup Rooftop Communications for its multipoint-to-multipoint radio technology, which is made to reach the places cable can’t. The radio in the RoofTop Wireless Routing product, which is generally installed (as the name suggests) on the roof of a building, acts as both an access device and a part of the network infrastructure, routing traffic for neighboring nodes. Nokia says that the technology enables its products to overcome line-of-sight issues.

Ambitious startup SkyPilot Network Inc. plans to create a nationwide wireless broadband access network using IEEE 802.11 wireless LAN kit arrayed in a mesh. The system is based around a series of nodes, situated on buildings, that pass data back and forth from a node that is linked to fiber in the ground. SkyPilot – with a CEO who’s a refugee from Covad Communications Inc. -- claims the system is considerably cheaper to use and maintain than DSL. The company is testing the system in Palo Alto, Calif.

Mesh networking, however, is not just being looked at as a cheaper way to broadband. This week, Caly Networks and ATDI have teamed up to promote a mesh networking technology that they say allows radio nodes in third-generation backhaul networks to communicate directly with each other, obviating the need for the base stations, which would cut costs for telecom operators struggling with the expense of 3G rollouts.

Meanwhile, on the smaller end of the scale, MeshNetworks Inc. has developed a wireless modem and accompanying software that it hopes will enable everything from cars to handheld devices to be linked in peer-to-peer networks. The company envisages its technology linking users in an ad-hoc fashion: For instance, if a group of users are all in the same small town and switch on their modems they’ll form a temporary network. Mesh Networks received an experimental license for its technology from the Federal Communications Commission (FCC) in January.

Since all these variations of mobile mesh networking are in their infancy, and there are few actual systems up and running, it’s hard to pinpoint potential problems with the technology. The reliability and range of the core technology behind all these systems -- radio -- is likely to be an issue. Most firms are using signal boosters in their nodes, but few will yet talk about performance in anything but general terms. There are bound to be issues with QOS, especially with the crowded 2.4GHz and 5GHz bands most of these technologies use.

— Dan Jones, Senior Editor, Unstrung
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