Wireless Home Networking - Index of

Chapter 5: Choosing Wireless Home Networking Equipment
� Power over Ethernet (PoE): Because every AP is powered by electricity
(where’s Mr. Obvious when you need him?), you should also consider
whether the location you choose for an AP is located near an electrical
outlet. High-end access points, intended for use in large enterprises and
institutions, offer a feature known as Power over Ethernet (PoE). PoE
enables electrical power to be sent to the AP over an Ethernet networking
cable so that the AP doesn’t have to be plugged into an electrical
outlet. Modern residential electrical codes in most cities, however,
require outlets every eight feet along walls, so unless you live in an
older home, power outlets shouldn’t be an issue. But, if you’re putting
the access point on the ceiling or in the attic, running one cable sure is
easier than running two!
There’s an IEEE standard for POE; it’s IEEE 802.3af.
� Detachable antennas: In most cases, the antenna or antennas that come
installed on an AP are adequate for good signal coverage throughout
your house. However, your house may be large enough or may be configured
in such a way that signal coverage of a particular AP could be significantly
improved by replacing a stock antenna with an upgraded
version. Also, if your AP has an internal antenna and you decide that the
signal strength and coverage in your house are inadequate, an external
antenna jack allows you to add one or two external antennas. Several
manufacturers sell optional antennas that extend the range of the standard
antennae; they attach to the AP to supplement or replace the existing
antennae.
The FCC requires that antennas and radios be certified as a system.
Adding a third-party, non-FCC-certified antenna to your AP violates FCC
regulations and runs the risk of causing interference with other radio
devices, such as certain portable telephones.
Detachable antennas are a potentially big benefit for 802.11g (and earlier
802.11a and b) systems, but not so much for 802.11n. Because of the
very tight integration between hardware and antenna in a MIMO
802.11n system, most 802.11n routers don’t offer detachable antennas
and wouldn’t benefit from them if they did. We expect that eventually
this will be an option, but as we write (during the early days of 802.11n),
detachable antennas aren’t really an option.
� Uplink port: APs equipped with internal three- and four-port hub and
switch devices are also coming with a built-in, extra uplink port. The
uplink port — also called the crossover port — adds even more wired
ports to your network by uplinking the AP with another hub or switch.
This special port is normally an extra connection next to the last available
wired port on the device, but it can look like a regular Ethernet
jack (with a little toggle switch next to it). You want an uplink port —
especially if you have an integral router or DSL or cable modem — so
that you can add more ports to your network while it grows. (And it
will grow.)
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