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The Point-to-Point of Wireless Bridging

Point-to-Point Performance
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We cast a wide net for our tests, inviting a dozen vendors of wireless point-to-point systems to send their wares to our Syracuse (N.Y.) University Real-World Labs®. Some do not have 5-GHz units at all, while some did not have devices ready for test, but we got products from six big names: Airaya Corp., BitRage, Proxim, RadioLAN, Wi-LAN and Young Design.

Several of the products we tested had just been released. And, as is typical of many emerging technologies, the performance, range and overall capabilities varied considerably, making head-to-head comparisons challenging. If product A offers twice the performance of product B but at half the range and double the price, does that make product A better? The answer, of course, depends on your needs.

The Basics

the products we tested work as wireless Layer 2 bridges. In an age where Layer 3 switches and routers dominate the market, you may wonder why these products are still running at Layer 2. The positive spin is that with a point-to-point system, you don't really need the sophisticated traffic-management capabilities of Layer 3 devices. In addition, many point-to-point systems will be linked to backbone routers anyway. Nonetheless, we would like more Layer 3 control--say, to filter certain protocols to optimize performance.

FCC Regulations for Select Unlicensed Radio Bands
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Although all the systems we tested are unlicensed and therefore must adhere to rules defined by the FCC and other international regulatory bodies, the underlying radios and modulation systems varied considerably from product to product in our tests. In most cases, it's a trade-off between price and performance. Packing more bits into each clock cycle requires more sophisticated radio technology--and you'll pay for that luxury. Because regulations vary by sub-band at 5 GHz, you'll get longer range from products that operate in the 5.8-GHz UNII-3 sub-band. The chart, "FCC Regulations for Select Unlicensed Radio Bands", shows some of the key regulations in the most commonly used unlicensed bands. We expect to see increased availability of low-cost chipsets that operate in the UNII-3 band, a development that will push the price-performance ratio lower.

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