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Mac OS, and vice versa. Luckily, as we note later in this chapter, most ven-
dors are moving towards browser-based configuration programs, which are a
lot easier to support than standalone configuration utilities.
90 Part II: Making Plans

As a general rule, if you™re using Windows 98 or 2000 (or Mac OS 9), make
sure that the devices that you buy will work up through Windows XP (and
Mac OS X). This will ensure your ability to use this wireless equipment in the
future if you upgrade parts of your network and will also help you get the
most value from your investment.

Form factor: Also, make sure the form factor (that is, the shape and form of
the device, like whether it™s external or a card) is what you™re looking for. For
example, don™t assume that if you have a tower PC, you should install a PCI
card. It™s nice to have the more external and portable form factors, such as a
Universal Serial Bus (USB) adapter because you can take it off if you need to
borrow it for something/someone else.

USB is supported by Windows 98 and later versions. Windows 95 does not
support USB ports. USB comes in two versions: USB 1.1 and USB 2.0. If your
computer has a USB 1.1 port, it has a maximum data transfer speed of 12
Mbps. USB 2.0 ports can transfer data at 480 Mbps, which is 40 times faster
than USB 1.1. If you plan to connect an IEEE 802.11a or IEEE 802.11g device to
a USB port, it must be USB 2.0.

Many brands of PC Cards include antennas that are enclosed in a casing that
is thicker than the rest of the card. The card still fits in the PC Card slot, but
the antenna can block the other slot. For most users, this shouldn™t pose a
serious problem; however, several manufacturers offer wireless PC Cards that
have antenna casings no thicker than the rest of the card. If you actively use
both of your PC Card slots, make sure that the form of the PC Card that
you™re buying won™t impede using your other card slot.

Even better, all cards should come from the same company that manufac-
tured the AP that you select to ensure maximum interoperability and to take
full advantage of any extended features that the AP offers.

Wall-mountability: If you plan on wall-mounting your device, make sure that
the unit is wall mountable because many are not.

Outdoor versus indoor use: Finally, some devices are designed for outdoor ”
not indoor ” use. If you™re thinking about installing this outside, look for
devices hardened for environmental extremes.




Bundled Functionality: Servers,
Gateways, Routers, and Switches
Wireless APs are readily available that perform only the AP function; but for
home use, APs that bundle additional features are much more popular for
good reason. In most cases, you should shop for an AP that™s also a network
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Chapter 5: Choosing Wireless Home Networking Equipment

router and a network switch ” a wireless gateway like we define in Chapter 2.
To efficiently connect multiple computers and to easily share an Internet con-
nection, you need devices to perform all these functions, and purchasing one
multi-purpose device is the most economical way to accomplish that.



DHCP servers
To create an easy-to-use home network, your network should have a Dynamic
Host Configuration Protocol (DHCP) server. A DHCP server dynamically assigns
an IP address to each computer or other device in your network. This function
relieves you from having to keep track of all the devices on the network and
assign addresses to each one manually.

Network addresses are necessary for the computers and other devices on
your network to communicate. Because most networks today use a set of
protocols (Transmission Control Protocol/Internet Protocol, or TCP/IP) with
network addresses (Internet Protocol [IP] addresses), we refer to network
addresses as IP addresses in this book. In fact, the Internet uses the TCP/IP
protocols, and every computer that is connected to the Internet must be
identified by an IP address.

When your computer is connected to the Internet, your Internet Service
Provider (ISP), such as America Online (AOL) or EarthLink, has assigned your
computer an IP address. However, even when your computer isn™t connected
to the Internet, it needs an IP address to communicate with other computers
on your home network.

The DHCP server can be a standalone device, but it™s typically a service pro-
vided either by a computer on the network or by a network router. The DHCP
server maintains a database of all the current DHCP clients ” the computers
and other devices to which it has assigned IP addresses ” issuing new
addresses as each device™s software requests an address.

Windows, Macintosh, and most other types of computers ” as well as net-
work devices ” can automatically communicate over the network with a
DHCP server to request the server to issue an IP address.



Gateways, NAT, and cable/DSL routers
A wireless gateway is a wireless AP that enables multiple computers to share
the same IP address on the Internet. This fact would seem to be a contradiction
because every computer on the Internet needs its own IP address. The magic
that makes an Internet gateway possible is Network Address Translation (NAT).
Most access points that you buy today are wireless gateways.
92 Part II: Making Plans



When your wireless network needs some order
Your home network comprises many parts. If know the WAN IP address in order for you to
you™re smart, you™ve consolidated these as have a good connection to the Internet. If the
much as possible because having fewer devices cable modem hasn™t renegotiated its connec-
means easier installation and troubleshooting. tion, it cannot provide that to the router. If the
But suppose that you have a cable modem, a AP comes back online before the router, it
router, a switch, and an access point ” not an cannot get its DHCP from the router to provide
unusual situation if you grew your network over connectivity to the client. Different devices
time. Now suppose that the power goes out. react differently when something is not as it
Each of these devices will reset at different should be on start up.
rates. The switch will probably come back fairly
Our advice: If you have a problem with your
quickly because it™s a simple device. The cable
connectivity that you didn™t have before the
modem will probably take the longest to re-sync
electricity went out and came back on, follow
with the network, and the AP and router will
these simple steps. Turn everything off, start at
come back up probably somewhere in-between.
the farthest point from the client, and work back
The problem that you, as a client of the DHCP toward the client, letting each device get its full
server (which is likely in the router in this startup cycle complete before moving to the
instance), have is that not all the elements are in next device in line ” ending with rebooting
place for a clean IP assignment to flow back to your PC or other wirelessly enabled device.
your system. For instance, the router needs to



A device that typically provides the NAT service to a home network is called
a cable/digital subscriber line (DSL) router or broadband router. (Note that
you can also purchase a broadband modem that doubles as a router, but the
typical modem is not a router.) Cable/DSL routers used in home networks
also provide the DHCP service. The router communicates with each com-
puter or other device on your home network via private IP addresses ” the
IP addresses assigned by the DHCP server. (See the earlier section “DHCP
servers.”) However, the router uses a single IP address ” the one assigned
by your ISP™s DHCP server ” in packets of data intended for the Internet.

In addition to providing a method of sharing an Internet connection, the
NAT service provided by a broadband router also adds a measure of security
because the computers on your network aren™t directly exposed to the
Internet. The only computer visible to the Internet is the broadband router.
This protection can also be a disadvantage for certain types of Internet gaming
and computer-to-computer file transfer applications. If you find that you need
to use one of these applications, look for a router with features called DMZ (for
demilitarized zone) and port forwarding that expose just enough of your system
to the Internet to play Internet games and transfer files. (Read more about this
in Chapter 12.)
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Chapter 5: Choosing Wireless Home Networking Equipment

A wireless Internet gateway is an AP that™s bundled with a cable/DSL modem/
router. By hooking this single device to a cable connection or DSL line, you can
share an Internet connection with all the computers connected to the network,
wirelessly. By definition, all wireless Internet gateway devices also include sev-
eral wired Ethernet ports that enable you to add wired devices to your network
as well as wireless devices.



Switches
Wireless gateway devices available from nearly any manufacturer include
from one to eight Ethernet ports with which you can connect computers or
other devices via Ethernet cables. These gateway devices are not only wire-
less APs but are also wired switches that efficiently enable all the computers
on your network to communicate either wirelessly or over Ethernet cables.

As we discuss in Chapter 2, there is a huge difference in performance
between a switch and a hub. Just because a device says that it has four ports
or eight ports doesn™t mean that it™s one or the other ” it could be either.
Look for words like switched LAN ports for an embedded switch in the device.

Even though you might intend to create a wireless home network, sometimes
you might want to attach a device to the network through a more traditional
network cable. For example, we highly recommend that you configure an AP
for the first time with the AP attached by a network cable directly to your
computer. At times, it might also be convenient to connect one of the other
computers in your home directly to your AP.



Print servers
A few multifunction Internet gateways add a feature that enables you to add a
printer to the network: a print server. Next to sharing an Internet connection,
printer sharing is the most cost-effective reason to network home computers
because everyone in the house can share one printer. Wireless print servers
have become a lot more economical in the past few years. However, when the
print server is included with the Internet gateway device, it™s suddenly very
cost effective.

The disadvantage of using the print server bundled with the AP, however, is
apparent if you locate your AP in a room or location other than where you™d
like to place your printer. Consider a standalone print server device if you
want to have your printer wirelessly enabled but not near your AP.
94 Part II: Making Plans


Operational Features
Most APs share a common listing of features, and most of them do not vary
from one device to the next. Here are some unique, onboard features that
we look for when buying wireless devices . . . and you should, too. Among
these are

Wired Ethernet port: Okay, this seems basic, but having a port like this
will save you time. We will tell you time and again to install your AP first
on your wired network (as opposed to trying to configure the AP via a
wireless client card connection) and then add on the wireless layer (like
the aforementioned client card). You will save yourself a lot of grief if
you can get your AP configured on a direct connect to your PC because
you reduce the things that can go wrong when you add in the wireless
clients. Note: On some APs, like the Mac AirPort, directly connecting for
setup is not an option.
Auto channel select: Some access points, such as some from ORiNOCO
(www.proxim.com), offer an automatic channel selection feature, which
is cool. For instance, the ORiNOCO AP-2000 Access Point selects its own
frequency channel, based on interference situation, bandwidth usage,
and adjacent channel use, by using its Auto Channel Select feature. This
is beneficial when first deploying your AP-2000 or adding an AP-2000 unit
in an existing environment. For instance, for the 5 GHz radio card (used
for 802.11a), the default channel is 52“5.260 GHz. When a second AP-
2000 unit is turned on in the vicinity of the currently active AP-2000
device, the Auto Channel Select feature changes the frequency channel
of the second unit so that no interference exists between the units.
Multiple AP-2000 units can be turned on simultaneously to establish
proper channel selection. That™s pretty nice because as you can read in
Chapter 6 and in the troubleshooting areas of Chapter 18, channel selec-
tion can try your patience. (You might wonder why it™s necessary to pay
more for more business-class access points ” this is a good reason.)
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 that you choose for an AP is located near an electri-
cal 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 out-
lets every eight feet along walls, so unless you live in an older home,
power outlets shouldn™t be a real issue. But if you™re putting it on the ceil-
ing, running one cable sure is easier than two!
Detachable antennas: In most cases, the antenna or antennas that come
installed on an AP are adequate to give you good signal coverage through-
out your house. However, your house might be large enough or be con-
figured such that signal coverage of a particular AP could be significantly
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Chapter 5: Choosing Wireless Home Networking Equipment

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 stan-
dard antennas; they attach to the AP to supplement or replace the exist-
ing antennas.
The FCC requires that antenna and radio be certified as a system.
Adding a third-party, non-FCC-certified antenna to your AP violates the
FCC regulations and runs the risk of causing interference with other
radio devices such as certain portable telephones.
Uplink port: APs equipped with internal three- and four-port hub/
switch devices are also coming with a built-in, extra uplink port. The
uplink port ” also called the crossover port, output, X, bridge, and so
on ” is used to add on even more wired ports to your network by
uplinking the AP with another hub or switch. This special port is nor-
mally 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

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