Primer: Making A Mesh Of Your WLAN

In the market for mesh? Here's a rundown of some of the leading providers of wireless mesh systems.

• BelAir Networks. BelAir was an early advocate of multiradio, carrier-class system design, but the company is branching out to the lower end of the market. Its high-end BelAir 200 offering, the keystone of its "cellular LAN" architecture, integrates up to four radios, high-gain directional antennas and standby batteries into a carrier-class enclosure designed to be mounted outdoors. Aside from providing outdoor access, the system is frequently used to beam Wi-Fi signals into buildings from the outside, akin to cellular phone services. BelAir's recently announced single-radio system, scheduled for availability this month, provides a lower-cost offering for installations where performance requirements are more modest.

• Firetide. While most mesh providers deliver both mesh infrastructure and Wi-Fi access, Firetide focuses on mesh infrastructure with an Ethernet interface that can be attached to a Wi-Fi AP or to any other Ethernet-capable device. Firetide has begun to develop mesh-based video surveillance, for example--a natural for a rapidly growing public-safety/homeland security market--using video gear originally designed for Ethernet networks. The company offers both indoor and outdoor products, aggressively priced from $695 to $1,995. Although the value is high, you won't get the capacity of competing multiradio system designs.

• Motorola. Motorola has focused heavily on public safety and government operations, where it has significant penetration with its radio systems. Its proprietary mesh offering is Mesh Enabled Architecture (MEA). Motomesh, Motorola's upcoming multiradio system, supports MEA radios and Wi-Fi concurrently and unlike MEA, emphasizes location-tracking capabilities. Motorola also has a multipoint fixed-wireless product line, called Canopy, that is sometimes used to provide backhaul services on Tropos' mesh networks.

• Nortel Networks. Nortel offers a dual-radio mesh system, called Wireless Mesh Network Solution, that uses 802.11g for access and 802.11a for mesh backhaul. Deployments include some universities and NASA, but the City of Taipei's network is the most interesting as a test of mesh scalability: The system is expected to include 10,000 mesh APs by the end of the year. Nortel is also a lead player in the Wi-Mesh Alliance.

• Strix Systems. Strix Systems made its entry into the market with its Access/One Indoor Wireless System (IWS), a spiffy modular multiradio design that lets you stack up to three radio modules into a single mesh node. More recently, the company has branched into the somewhat hotter outdoor market. Its Outdoor Wireless System (OWS) combines up to six radios into a single NEMA enclosure, which provides considerable flexibility. The outdoor system also interoperates with its indoor system, facilitating indoor/outdoor installations. Unlike Belair's outdoor system, Strix's offering does not include integrated antennas. This enhances system flexibility but complicates installation (and detracts from aesthetics).

• Tropos. Tropos is a leader in the market by virtue of its large installed base. Its single-radio 802.11g system design is aggressively priced and easy to deploy. To overcome the limitations of the single-radio design, Tropos uses its predictive wireless routing protocol (PWRP) to optimize routing decisions and minimize routing overhead. Still, the company's recommendation that the number of intermediate mesh hops shouldn't exceed two is a clear indication that its mesh is capacity-constrained. This means that a much larger proportion of mesh routers needs to be connected to the wired network. Where this is impractical, Tropos often employs Motorola's Canopy 5 GHz multipoint backhaul system.