Compatibility
So how do you successfully navigate this alphabet soup of standards? All of the Wi-Fi variants (802.11b, g, and n products) use the same 2.4 GHz radio frequency, and as a result are designed to be compatible with each other. This means you can usually use devices based on the different standards within the same wireless network. The catch is that doing so often requires special configuration to accommodate the earlier devices, which in turn can reduce the overall performance of the network.
Moreover, wireless network hardware manufacturers sometimes use non-standard technology enhancements to increase performance. Such features may not be compatible with devices from other vendors, and may even need to be turned off when not supported by every device on the wireless network.
The bottom line is that in an ideal scenario you’ll want all your wireless devices—the access point and all wireless-capable computers—to be using the same technology standard and to be from the same vendor whenever possible. Of course, this isn’t always possible, so just remember that mixing and matching wireless hardware, while possible, may require some tweaking and won’t always deliver the best results.
Speed
When you buy a piece of wireless network hardware, it will often quote performance figures (i.e., how fast it can transmit data) based on the type of wireless networking standard it uses, plus any added technological enhancements. The crucial thing to know about these numbers is that they’re like the miles-per-gallon ratings associated with cars—put simply, your mileage may—in fact will—vary, often considerably.
In truth, performance figures plastered on product boxes or marketing literature are almost always wildly optimistic. While the official speeds of 802.11b, 802.11g, and 802.11n networks are 11, 54, and 270 megabits per second (Mbps) respectively, these figures represent a scenario that’s simply not attainable in the real world. (It’s just like how you don’t actually get to pocket your full annual salary because of deductions for taxes and so forth.)
In a nutshell, always treat wireless network performance quotes with a high degree of skepticism. As a general rule, you should assume that in a best-case scenario you’ll get roughly one-third of the advertised performance.
It’s also worth noting that a wireless network is by definition a shared network, so the more computers you have connected to a wireless access point the less data each will be able to send and receive. It’s like when you cook for four and six people show up; everyone still gets to eat, but there’s less food to go around. (One way to improve the performance and capacity of a wireless network is to use more than one access point.) Continue to Page 3
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