Wireless Networking's Next Wave

A crucial T1 connection to Verizon was down, but the court system was in the middle of a project to build its own fiber-optic network connecting all the buildings. A link to one of the courthouses remained up, so Guo and his team used the new fiber network to share connectivity throughout the complex.

Two locations remained dark; they sat astride a historic burial ground, the existence of which had delayed installation of the fiber network. Guo turned to Canobeam, an optical wireless system from Canon USA Inc. that uses two transceivers, each of which looks like an oversized security camera. When mounted on a roof or a wall and pointed at each other, the devices create a high-bandwidth data connection using laser light.

Three days after Guo called the company, on the Monday after the attacks, the connection was up, and service to all the courthouses was restored. The connections had more bandwidth--a typical T1 line runs at 1.5 Mbps, but Canobeam devices run up to 100 Mbps, and newer transceivers available from Canon run at speeds up to 1.25 Gbps. "When the T1 came back up, we canceled it," Guo says.

But many companies worry about the reliability of optical wireless. Laser systems require a direct line of sight from transceiver to transceiver, and anything that blocks that line can interrupt the signal. Optical transmissions can also be stymied by bad weather. In heavy rain or snow, particles of water passing through the beam can degrade the connection, but that generally causes slower data speeds and doesn't stop the connection. "More than 99% of the time, it's working great," Guo says.

Guo investigated traditional 802.11b wireless LANs to make these connections, but found that the Wi-Fi point-to-point connection just wasn't reliable enough and didn't provide the bandwidth he needed. It's cheaper, he says, but doesn't provide the performance.

Now the court system is using the technology in other locations, such as New York City areas where digging fiber is expensive, or where geography prevents laying wires. In Riverhead, N.Y., the Peconic River separates two courthouses, and the two buildings are connected by Canobeam. Canobeam hardware and installation costs about $40,000.

Still, most organizations are reluctant to use wireless technologies as the foundation for an IT infrastructure. New high-speed standards promise to make it easier to connect people to business networks, whether they're inside their offices or across town. Adoption is likely to be slow, but wireless technology is improving its track record of success, and making technology executives more comfortable trusting a greater part of network traffic to wireless. "A couple of years ago, maybe we would have worried," says OrderMotion's Christensen. "But now, not at all."