IN THIS APPENDIX
Wi-Fi is a certified version of variants of the 802.11 wireless standards developed by the IEEE (http://www.ieee.org). Wi-Fi equipment is certified by the Wi-Fi Alliance (http://www.wi-fi.org) for compatibility and standards compliance.
The 802.11 wireless standards, also called protocols, are designed to use the so-called free spectrums, which do not require specific licensing. The spectrums currently used by 802.11 are 2.4GHz and 5GHz. (The 2.4GHz spectrum is also used by household appliances such as cordless phones. Microwave ovens also generate noise/interference in this radio spectrum, which can impact the performance of wireless devices.)
You don't need to know or give a fig about wireless standards or 802.11 to happily use wireless networking on the road or in your home network. That's why I've kept this material out of the body of Anywhere Computing with Laptops: Making Mobile Easierbecause you don't really need to know it unless you are practicing to be an engineer.
But in case you are curious, I've summarized the most important concepts that underlie 802.11 (and Wi-Fi) in this appendix. Oh, and if you go into a store and a salesperson starts spouting "802.11 this and 802.11 that," you can check the summary of the 802.11 variants in "The Flavors of 802.11" and know exactly what is being talked about (quite likely better than the salesperson).