802.11n: How Best to Use It and When
If your company has traveling employees, bandwidth-hogging applications, a need for speed or just a desire to keep pace with technology, you're probably thinking about moving to an 802.11n-based wireless networking infrastructure, at least at the network's perimeter.
It's inevitable, experts say, and the numbers bear it out. ABI Research, an Oyster Bay, NY, market research firm, finds that while 802.11n has only a 2.3 percent penetration rate in North America today, that number will grow exponentially, reaching 19 percent by next year. In large part, that's because the technology is mature, costs have decreased, and it has the flexibility that wireless can't compete with, says Stan Schatt, vice president and research director for wireless connectivity at ABI Research.
Although the standard isn't fully approved -- it's expected to be available by 3Q09 at the latest -- it's finished, for all intents and purposes, she says, and most major vendors have 802.11n products ready to go.
With products already available and companies hungry for the throughput and flexibility 802.11n will provide, the only decisions left involve how to choose and implement the technology most effectively and efficiently.
The first step is performing a thorough site survey, evaluating your current technology infrastructure and future needs.
"Now is the time to spend the money and time to look at your needs," says Lisa A. Phifer, vice president of Core Competence Inc., a Chester Springs, Penn., network and security consultancy. "You have an opportunity to start with a clean slate with a brand new set of products and do it right the first time. You'll spend less money in the long run."
Once you know what you need, the next step is choosing a product and a vendor, which is more difficult than it may seem. There are major differences in terms of robustness, capacity, flexibility and manageability.
"You have to consider everything. For example, what if your controller goes down? Some access points are capable of going into independent mode and some aren't," says Schatt. "And there are significant differences in antenna technology; some companies like Motorola and Ruckus have put a lot of effort into their antennae to accentuate the advantage of the MIMO (multiple input/multiple output), while others haven't."
Don't be afraid to ask vendors the tough questions, especially about features that are important but don't get much airtime in websites and collateral, adds Michael Fineran, a principal at dBrn Associates, a consultancy in Hewlett Neck, NY.
For example, few vendors mention how many transmit chains their products provide. That's important, because while 802.11n provides the ability to send multiple signals at the same time in the same frequency band, two chains would provide twice the transmission capacity of one chain. "That's not something they tell you, so you have to ask," Fineran says.
Another important factor is maximum transmission rate. Although all vendors quote one, they often don't say whether it's 20MHz or 40MHz. It's an important consideration, he adds, because that determines the bandwidth and the number of available channels.
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