The Airaya AI108 was the only product we tested that is based on the same Atheros chipset that is widely implemented in 802.11a WLAN products. This lets Airaya take advantage of low component costs while delivering excellent performance. The big trade-off is range. Because the AI108 operates in the 5.25-to-5.35-GHz UNII-2 band, it is limited by the FCC to a maximum of 1 watt of radiated power at the antenna. At deadline, Airaya's Web site indicated that the product had not yet received FCC certification, though the company assured us certification was imminent. Airaya says it plans to add support for the UNII 5.8-GHz band, which allows for higher radio output levels, early next year.
Like Wi-LAN's and Proxim's offerings, the AI108 integrates the radio and antenna into a single enclosure. Power-over-Ethernet is supported, so a single cable supplies both power and network connectivity. During performance testing on the early production unit supplied to us we experienced unit failures that were quickly traced by Airaya back to a faulty power supply. Airaya sent us a new device that performed without problems, along with assurances that its quality-assurance program has been improved to ensure that customers don't experience this problem.
The bridge comes with a factory default IP address. This let us access the integrated Web configuration utility, which is protected by a username and password. The Web page included an option to choose a channel (only a single channel was available in the unit we received) and data rate. The bridge lets you select data rates of 108, 54, 48, 36, 24, and 12 Mbps, but if you choose "best," the rate will be set to the highest possible rate automatically. Those of you familiar with 802.11a will recognize these data rates. In essence, Airaya is binding two 11a channels to achieve a raw data rate of 108 Mbps. The Web configuration utility includes an antenna-alignment tool, but it didn't work in the version we tested. After consulting with Airaya, we were told the feature is available in the current firmware release, which we did not have time to test before deadline.
Some users may be concerned that using an 802.11a chipset for a point-to-point bridge could expose the system to hacking by 11a users who are able to intercept the radio signals. Airaya addresses this problem by using a nonstandard, center-channel frequency. It also implements a proprietary 152-bit encryption algorithm.