Choosing a wireless technology

After you know what you’re networking and what will be on your wireless network,
you have to decide how to network wirelessly. As we discuss extensively
in Chapter 2, four main variants of wireless networking technologies
exist: 802.11a, 802.11b, 802.11g and 802.11n (draft standard).
Collectively, all these technologies are usually referred to as Wi-Fi, which isn’t
a generic term, but, rather, refers to a certification of interoperability. The
folks at the Wi-Fi Alliance (www.wi-fi.org) do extensive testing of new wireless
gear to make sure that it works seamlessly with wireless equipment from different
manufacturers. When it works, it gets the Wi-Fi logo on the box, so you
can rest assured that it works in your network.

Wi-Fi certified gear works together — as long as it’s of a compatible type. That
means that any 802.11b, 802.11g, or 802.11n Wi-Fi certified gear works with
any other equipment of that type; similarly, any 802.11a Wi-Fi certified gear
works with any other 802.11a and 5 GHz capable 802.11n gear that has been
certified. (Note that not all 802.11n gear is 5 GHz capable — if a particular
piece of equipment supports this, it will say so and will also be 802.11a certified.)
802.11b and g gear does not work with 802.11a gear, even if it has all
been certified because they work on different radio frequencies and cannot
communicate with each other.
The discussion of wireless technology quickly degenerates into a sea of
acronyms and technospeak. If you need a refresher on this alphabet soup —
or to begin from square one — Chapter 2 is a primer on jargon, abbreviations,
and other nuts-and-bolts issues.
For home users, the three most important practical differences between
802.11a, 802.11b, 802.11g, and 802.11n networks are speed, price, and
compatibility.

802.11b is an older standard that is no longer used these days. You would
be hard pressed to find any 802.11b in your network, and only if you have
been buying legacy equipment at flea markets or electronic junk yards.
802.11g equipment has been the standard in use for a few years. Thanks
to its proliferation, it’s inexpensive but at least four times faster than
802.11b.
802.11a can still be found in some special-use corporate environments,
but it’s no longer used in the home. It is as fast as 802.11g, costs much
more, and has a shorter range.
802.11n is five times faster than 802.11a and 802.11g and is 22 times
faster than 802.11b.
802.11a and 802.11b are not compatible.
802.11a and 802.11g are not compatible.
802.11b and 802.11g are compatible.
802.11n is compatible with all other standards but at the cost of its
higher speed — when you add 802.11a, b, or g gear to an 802.11n network,
you slow down the ultimate throughput or speed of that network.
The 802.11n standard is compatible with all other standards, but not all 802.11n
equipment supports both the 2.4 GHz (802.11b and g) and 5 GHz (802.11a) frequencies
— many support only 2.4 GHz. An AP that includes 802.11n should
work with any other device as well (though not always at the higher 248 Mbps
speed of 802.11n). Thus, you don’t have to look for a multimode AP.
If your primary reason for networking the computers in your house is to
enable Internet sharing, 802.11g is more than fast enough because your
Internet connection probably won’t exceed the 54 Mbps of the 802.11g connection
any time soon — unless you’re one of the lucky few who lives where
fiber-optic Internet services (such as Verizon’s FiOS service) are installed.
Despite the fact that most Internet services are slower than 802.11g, we don’t
recommend that you buy only 802.11g gear. 802.11g is being superseded by
802.11n with full 802.11g compatibility. In fact, you would save only a few
bucks by buying 802.11g gear new. The speed, range, and compatibility of
802.11n are more than worth the increased price tag.
802.11g is the minimum standard around which you should build your network.
If you want to hedge your bets, look for an 802.11n AP that can handle all Wi-
Fi technology standards. Apple, Belkin, NETGEAR, D-Link, and several other
leading manufacturers of wireless home networking equipment already offer
802.11n wireless devices.