The Beginner's Guide to Wi-Fi
Everything You Need to Know About Wireless Networking
by Michael Fortner
Copyright 2004 by Wellness Publishers,L.L.C.
Here is everything you need to know about wireless
networking, from how it works, to explanations of
the various standards and products.
Tabel of Contents
Introduction
Wireless Fidelity
Wi-Fi Equipment
Understanding Network standards
Limitations & Drawbacks
Hotspots
Basic Network Security
Wireless Entertainment
Expanding Your Network
The Future of Wi-Fi
Networking Reference Guide
End Notes and Bibliography
Introduction
Wi-Fi Means Mobility
No other networking technology in a small home or office
provides the convenience or mobility of a Wi-Fi network. That's
because other methods, including standard wired Ethernet
networks and phone-line and power-line based networks, all
require a connection via wire or cable. Wi-Fi uses radio waves
that travel through walls and floors and connect you anywhere,
indoors or out, if you are within range of the antennas.
Wi-Fi Connects You
Imagine working on your laptop or checking e-mail from
anywhere in your home. Imagine being able to connect to your
office network from an airport or coffee shop. Imagine
retrieving files or presentations from the corporate network,
cruising the Internet or sending instant messages to coworkers—and doing it all
from a conference room or the company cafeteria. Now,
imagine doing all these things easily and quickly, without
worrying about finding a wired network connection. That is WiFi.
Imagine being able to move your entire office without losing
your investment in networking installs, or to add new staff, all
without moving cables or installing complicated hubs and
routers. That is Wi-Fi
Wi-Fi networks also work well for small businesses, providing
connectivity between mobile salespeople, floor staff and
behind-the-scenes finance and accounting departments.
Because small businesses are dynamic, the built-in flexibility
of a Wi-Fi network makes it easy and affordable for them to
change and grow.
Who Can Use Wi-Fi?
Everyone can use Wi-Fi, almost everywhere in the world.
Home Wi-Fi networks can connect multiple computers to each
other, to other devices and to the Internet. A Wi-Fi network
can connect a family's computers and entertainment devices
together to share hardware, software and data resources. That
means everyone in the family can access or share stored files,
photos, sound and video - all without unsightly cables running
throughout the home.
In a home or home office, Wi-Fi deployment gives you the
ability to share a single high-speed broadband cable or DSL
connection. A Wi-Fi network can easily be expanded to an
almost unlimited number of users. Wi-Fi networks work
especially well for small businesses, providing connectivity
between mobile salespeople, floor staff and behind-the-scenes
finance and accounting departments. Because small
businesses are dynamic, the built-in flexibility of Wi-Fi
networks makes it easy and affordable for them to change and
grow.
Wireless Fidelity
Wi-Fi is short for Wireless Fidelity. Like cordless phones and
garage door openers, Wi-Fi uses radio waves to send
information between two computers, PDAs, and a growing list
of common electronic devices, but is used mostly for
connecting to the internet. Wi-Fi means freedom beyond the
limitations of an internet wire.
It was originally created for business travelers who wanted a
way to connect to the internet, and is blossoming into a major
industry. Wi-Fi has expanded into offices, homes, cafes,
shopping malls, airports, hotels, golf courses, and university
campuses. Cities such as Long Beach and Milwaukee are
offering free Wi-Fi in areas of downtown, such as two city
parks in Milwaukee.
A home user can sit in the backyard and listen to the birds sing
while paying bills online or checking email. Mom can now take
her computer from room to room as she watches the kids or
watch them via a wireless camera, and sports enthusiasts can
use it to get stats while watching a game on TV.
Wi-Fi Equipment
To get hooked up at home you will need a high speed
connection such as DSL or cable (dial-up access will not work
with Wi-Fi), and a laptop (preferably with an Intel Centrino chip
designed for Wi-Fi functionality). Desktop computer and
printers can also be hooked up to a wireless network. Most
new laptops and PDAs come equipped with a Wi-Fi card. You
will also need is a transmitter in one or two locations of your
home and you are good to go.
Router
The gateway or hub of a wireless network is a router which is
also an Access Point. Routers connect to DSL, satellite
broadband, or cable, and sends data to laptops at speeds four
times greater than the fastest DSL or cable speed. Routers
control the flow of information between the network and the
internet. Routers will either connect to the broadband modem,
or will include a cable or DSL modem. They have built-in
firewalls for added security, and some have more advanced
security features. The router can also connect a desktop
computer not hooked up to the wireless network, using
standard DSL line.
Price ranges form $53.00-73.00.
The Buffalo AirStation Broadband Router
AP incorporates improved security with
VPN support, and upgradeable firewall
features. The built-in, 4-port Ethernet
switch allows you to combine wired and
wireless networks on the same LAN. The
Broadband Router AP also supports up
to 40Mbps router throughput and will
protect your investment when higher
broadband rates become available
(currently, typical throughput is 27Mbps).
Access Point
A Wi-Fi network may need an additional transmitter, also
called an Access Point (AP). Wireless Access Points do not
provide the features and configurability of most routers
because they are not intended to be the hub or central
gateway, but merely to add an extension to the wireless
network.
Prices range from $39.00-$210.00.
NETGEAR's HE102 802.11a Wireless
Access Point provides users
untethered access to the network and
Internet whether in their conference
room, home, classroom or cafeteria.
You can create a network from the
ground up or extend your wired
network to accommodate new
locations and users. With blazing
speeds you can deploy highbandwidth applications never before
possible. Share presentations and
collaborate on graphics-intensive
projects without being tied to your
desk. Protected with industrystandard 64/128/152-bit WEP
encryption.
Adapters
An adapter is a radio connection that fits into your computer or
PDA. If your computer doesn't have a built in adapter, you can
connect one with an external adapter. Be sure to get the same
standard as your router, such as 802.11a, b, g, or Bluetooth.
There are several different types: PC Cards, PCI and miniPCI, USB, CompactFlash, and SD.
Some adapters have extra features, such as retractable or
removable antennae, encryption, or even connectionmonitoring software.
Price ranges from $86.00 to $119.00.
Proxim's ORiNOCO 802.11a/b/g Gold
ComboCard delivers the utmost in mobile
convenience and performance, allowing
secure connections to 802.11b, 802.11a,
and 802.11g networks from a single card.
You can move easily between 802.11
networks at work, home, and in public
spaces.
A few years ago a Wi-Fi antenna (AP) cost about $300, but is
now priced at $40.00 and up (the same for routers). A Wi-Fi
card costs $65-$100. Always buy equipment that is Certified
by the Wi-Fi Alliance. Just look for the "Wi-Fi Certified" logo.
Certified products undergo rigorous testing to insure that they
are functionally compatible with another company's products.
Noncertified products have compatibility issues and
"catastrophic failure rates." (1)
Understanding Network standards
Perhaps the most important decision you will make is the
standard you choose to install. The standard influences
everything-- speed, features, signal reach, and the cost of the
network. It can be confusing at first glance, so here's a quick
guide to what you need to know about network standards.
Network
standard
Speed
Range
Frequency &
interference
Hotspot
access
Power
drain
Cost
802.11b
5-11Mbps
100-300
feet
2.4GHz; high
Excellent
Moderate
Low
802.11a
22-54Mbps 60-100 feet
5GHz: low
Poor
High
High
802.11g
20Mbps
150-250
feet
2.4GHz; high
Excellent
Moderate
Moderate
Dual band
22Mbps
150-300
feet
2.4GHz,5GH
z
Excellent
Moderate
High
Bluetooth
300700Kbps
20-50 feet
2.4GHz; high
Poor
Low
Moderate
High-speed data transfers can be expected in the above listed range. Beyond those
distances, the farther away you are from the access point, the slower the transfer speed.
802.11a, 802.11b, 802.11g, and Bluetooth are different radio
bands such as AM and FM. The 802.11b has a data transfer
rate up to 11Mbit/sec, while 802.11a and 802.11g transfer
data up to 54Mbs. But 802.11a has a much lower risk of
frequency interference than b and g. A dual-band device can
use either standard. Bluetooth is used for handheld computers
and PDAs, but can be used with computers as well.
802.11b is the dominate standard, and 802.11b based
equipment are the lowest in price. It operates at 2.4GHz with
potential interference from cordless telephones, garage door
openers, microwave ovens, security radios, and baby
monitors. It is compatible with 802.11g.
802.11a standard has the advantage of operating at a different
less populated frequency (5.15GHz to 5.35GHz) than 802.11b,
so it is less likely to experience signal interference. Its high
speed data transfer is better for streaming audio and video or
transferring large files, with bandwidth left over. However,
802.11a has a shorter range. A major limitation is that most
hotspots utilize the 802.11b standard. If you expect to use
public hotspots while traveling, then 802.11a is a bad choice.
The two standards operate at different frequencies, so they
can't communicate with each another. The 5Ghz radio also
has an greater power drain on labtop batteries compared to
2.4GHz.
802.11g has the speed of 802.11a but operates at 2.4GHz like
802.11b, therefore 802.11g equipment can be used with
802.11b equipment. Therefore, 802.11g is the standard of
choice when adding to or upgrading an existing 802.11b
network. The only drawback is the possible signal interference
of 2.4GHz, when operating in an area with other such devices,
including Bluetooth.
Dual band
Dual-band equipment offers the ability to switch between the
different standards, thus insuring that you will always have the
best possible connection. But it cost twice as much as singleband equipment. With dual-band you will be able to use
802.11a at home and 802.11b with hotspots.
Price ranges from $227.00-$279.00.
Linksys WRT55AG Dual-Band
Wireless A+G Broadband Router
combines four devices — a router,
switch and two wireless access points
in a single unit. The router lets you
securely share one high-speed
Internet connection among your entire
network.
Bluetooth is slow, 500Kbps, compared to the other standards,
but offers more flexibility and its range is much shorter.
Bluetooth equipment can work with little or no preparation. It
has better range than infrared and is not limited by the line-ofsight operation of the infrared requirement. Therefore,
Bluetooth is expected to eventually replace infrared.
Since it has low power requirements it can be used in handheld devices such as PDAs. Attendees at conferences can
transfer files across the table with Bluetooth-equipped handheld devices or notebooks. They can also print through a
Bluetooth-equipped printer without downloading drivers.
"Bluetooth may soon be standard equipment on
many cell phones and handheld computers. There's
even talk of putting Bluetooth into home appliances.
But for all the theoretical benefits of Bluetooth, the
reality is that it's currently a mess of incompatible
hardware and software. It operates at 2.4GHz, so is
subject to interference problems the same as
802.11b and 802.11g. " (CNET.com)
Price ranges from $23.00-$34.95.
Now you can truly enjoy the freedom of
wireless connectivity with Actiontec's USB
Bluetooth Adapter. Simply plug this tiny
adapter into any USB port on your computer,
and you can exchange information between it
and any other Bluetooth enabled device.
HomePlug
"Power-line gear may be the best-kept secret in home
networking," says CNET.com. Powerline, also known as
HomePlug, is a good way to have a wireless (not counting the
electrical wires) network without radio interference or security
issues, and at a lower cost. HomePlug can reach to far
distance areas of a large building, which Wi-Fi cannot.
HomePlug uses a home's electrical wiring to connect a
network, with transfer speeds of about 5Mbps. HomePlug
routers and adapters have no compatibility problems, they will
all work with other HomePlug devices.
Price ranges from $79.00-$95.00.
The D-Link DHP-100 is a plug-and-play Ethernetto-Powerline Bridge providing a convenient way to
extend the range of a wireless access point or
router. It is especially useful for homes or small
offices when concrete walls, elevator shafts,
successive floors in multi-storied buildings, or other
architectural impediments inhibit the wireless
signal. Two or more D-Link DHP-100s can extend a
wireless access point or router's range. The D-Link
DHP-100 is fully compliant with HomePlug
PowerLine Alliance Industry Specification v1.0.
Limitations & Drawbacks
A single access point can connect 15-20 computers, provided
they do not require excessive amounts of data. Just surfing the
web or checking email only uses bursts of bandwidth, but if 10
computers were all downloading large files at the same time,
they would each only get 10% of the normal speed.
And you cannot print with Wi-Fi unless your printer is wireless
equipped, or you send the signal to a desktop computer which
is connected to the printer.
Drawbacks of Wi-Fi include signal interference and bandwidth
stealing. Interference is often caused by cordless phones,
microwave ovens, metal shelving, concrete walls, ham radios,
and even glass which acts as a reflector. Small businesses
also must guard against people walking around looking to
steal their connection (war-walking), driving around (wardriving), and making chalk marks on the pavement to let
others know where they can steal your connection (warchalking). You do not want Wi-Fi if you live in an apartment
because people in the next dwelling or standing outside can
use your connection.
Hotspots
A hotspot is an area with public access points. You can turn on
your computer while away from home and it will detect the
presence of an AP if one is available. But where are they? You
can walk around trying to find one, or you can buy handheld
devices that can detect the presence of hotspots, but they do
not work well. The best way to find them is through web sites
that list all the legally available hotspots in the world.
Wi-Fi Zone
Wi-Fi 411
Wi-Fi Free Spot
Hot Spot List
Intel Hotspot Finder
Public access does not always mean free. Many places
charge to connect unless you buy some of their product.
Hotspots in parks and downtown may also require payment by
the day, hour, or even minute. And in order to use the feebased hotspots you must have an account with one of the
wireless internet service providers. A standard DSL or cable
service provider is all that is needed at home or at the office to
use wireless, but to connect to many hotspots you need an
account with Bingo (www.bingo.com), STSN (www.stsn.com),
T-Mobile (www.t-mobile.com), or Wayport (www.wayport.net).
Basic Network Security
The equipment you have and the layout of your network will
determine what security you'll need. A few basic measures are
required for an acceptable security level.
Wireless devices come equipped with security such as WEP
(Wired Equivalent Privacy), which comes in 64/bit and 128/bit
encryption, but it can be hacked. The newer WPA (Wi-Fi
Protected Access) is secure enough for most home and small
business users, and is now required for product certifications
given since September 2003.
"Wi-Fi Protected Access meets the wireless LAN
security needs of both enterprises and individuals,"
said Wi-Fi Alliance Managing Director, Frank
Hanzlik. "This is a very robust, cross vendor
interoperable security technology that is both easier
to install than its flawed predecessor WEP and far
more secure. The Wi-Fi Alliance recommends that
WEP be dropped in favor of WPA for applications
as soon as feasible." (2)
But like Windows XP, wireless equipment do not come with
security enabled as the default setting; users must be sure to
enable security when they install Wi-Fi. But even without
security you can still shop online because secure web pages
send your credit card number encrypted. The weakest link in
Wi-Fi security is in fact the end users, who can be tricked into
giving out their passwords and user IDs.
Other security features include a hardware firewall
found in most routers. Hardware firewalls do their
own port filtering and encryption tasks, with little or
no resource drain on your computers.
MAC address filtering is an additional security
measure. MAC (Media Access Control) is the
unique physical address of each network device,
which can be assigned by the user. Any device who's address
is unrecognized will not be allowed access to the network.
Without this security someone standing outside your home or
office could use your Wi-Fi connection and even have access
to your private files.
However, these security measures only protect your wireless
network; once your signal leaves the network via your router
(gateway), it is no longer encrypted, unless you are shopping
on a site with SSL, or when using VPN (Virtual Private
Network), which is for corporate users connecting to their
company's network. Home users who access the internet must
have a software firewall and antivirus software. Software
firewalls such as ZoneAlarm and Kerio Personal Firewall are
free and work well. It is recommended that you purchase
antivirus software in order to get the best protection and
immediate updates when a new bug or worm is spreading over
the net.
Wireless Entertainment
A new device called a Digital Audio Receiver (DAR), sends
music to your stereo from your PC, and supports several
different networking standards: wired Ethernet, 802.11b, FM,
USB, HomeRF, even phone-line networking. With new
multimedia devices someone who downloads movies can
watch them full-screen on their television set. Other devices
can connect with or take the place of slide projectors.
Price ranges from $136.00-$152.00.
The Grandtec GWB-4000 Ultimate Wireless
is the world's first truly wireless PC-to-TV
converter system recommended for
professional presentations, computer
gaming, and Internet browsing on TV. The
GWB-4000 is a wireless PC to TV system
that converts both audio & video for use
with any TV!
EZ-Stream Universal 2.4GHz/5GHz Wireless Multimedia Receiver is the
industry’s first Universal Wireless Home Entertainment Networking
device in the market. It works with all the 802.11 Wireless Standards
available – whether it is the popular 802.11b, the emerging 802.11a, or
the new 802.11g. EZ-Stream UWM Receiver delivers your networked
PC’s collection of MP3 songs, digital photos, digital music video or
movies to your Home Entertainment Center or Audio System.
Simply connect the receiver to your TV or stereo system via a standard
Audio/Video Cable, and load the EZ Installation Wizard for the Media
Server Software on your networked PC. The Media Server software is
easy to use and configure.
The Wireless-G Game Adapter can be used in two
different ways. If you have an existing home wireless
network and a cable or DSL Internet connection, the
Game Adapter lets your PlayStation®2, Xbox™ or
GameCube™ attach to the network so you can get into
online games without running wires to the game room.
It's completely driver-free, so it works on any platform.
Setup is a snap. In some cases, it works right out of the
box!
The Game Adapter provides lag-free gaming with
communication speeds up to 54Mbps when connected to
other Wireless-G devices. It can also connect to
Wireless-B (802.11b) devices and networks at 11Mbps.
Expanding Your Network
With wireless repeaters and bridges you can connect with your
friend across the street or across campus, or create a
community network. A repeater picks up the signal and sends
it off again at full strength to make a wireless network reach to
far ends of a building or to the next building. Bridges connect
two networks together. Bridges tend to work only with other
bridges of the same type and model.
Perhaps you just need to extend your range a few yards, in
which case an antennae or signal booster (amplifier) will work.
An antennae is preferred over an amplifier because the noise
and interference also increase with an amplifier. Long range
antennae can reach across landscape where no bridge or
repeater can be plugged in. Uni-directional antenna sends the
signal in one direction, which keeps your neighbors from
receiving it, while an omni-directional antenna sends the signal
out in all directions.
Price ranges from $112.00 - $139.00.
This external outdoor Omni Antenna for
11Mbps Wireless LAN AirStations connects to
the AirStation Access Point, extending the
range of your wireless network environment. It
can also be used with 2.4GHz wireless
communication devices to communicate
between buildings or other point-to-point
situations.
With a wireless security camera you can keep an eye on the
kids playing in the pool while you are in some other part of the
house. You can also watch what is happening inside or
outside your home from anywhere in the world.
Prices range from $139.00 - $250.00.
The D-LinkAir DCS-1000W is a
versatile 802.11b Wireless Internet
camera with VGA quality resolution. An
ideal solution for remote security
monitoring or broadcasting of live
events over the Internet.
Price ranges from $99.00 - $172.99.
The DCS-900 from D-Link delivers live
video over the Internet for real-time
viewing and monitoring. This Internet
Camera combines the functionality of
video surveillance with the reliability
and scalability of Fast Ethernet.
The Future of Wi-Fi
The future of Wi-Fi is very bright. Its growing in popularity
because of decreasing costs and the freedom it gives to users.
Many offices are going wireless because its less expensive
than hardwiring all their desks, which must be rewired
whenever desk areas are moved or the company moves to a
new location. Wi-Fi is also being used in warehouses and
other remote areas, which increases productivity.
Business travelers and home users on vacation can connect to
the internet through an estimated 24,000 public Wi-Fi
networks worldwide, and expanding rapidly as businesses
such as Starbucks, Kinko's, and MacDonald's offer Wi-Fi in a
growing number of their locations. Public Wi-Fi could be the
fastest growing area, and will soon be available in many
downtown areas and even along major highways, allowing
users access wherever they stop.
There are expected to be 99 million Wi-Fi users by 2006, with
89,000 public access points worldwide, says Gartner
Research.
Wi-Fi is considerate an emerging technology, which means
there are still many new products being developed that will use
the technology, as well as new ways of using it. You can now
buy stereos with wireless speakers, and even a 15 inch battery
powered television set with a wireless cable connection. It is a
bit pricey at over $1,000.00, but it is an example of the growing
number of wireless products. More and more of these
products will be able to hookup to your PC and/or other
household devices.
In the future you can look for scanners, cameras, DVD players
and recorders, and even appliance controllers, coming
equipped with Wi-Fi. There are even new standards being
developed such as 802.16.
Networking Reference Guide
Home network
You can buy a networking kit that includes all the basic
components, or you can buy the components separately. What
you need will depend on how many computers and perifrials
you will connect and how you will use them.
Required Components
Device
What it does
Cable/DSL router
Connects the internet to Access
Point
stationary wireless device that
Wireless Access Point sends information to a wireless
computer
Wireless adapter (PC Card)
Power-line adapter
Connects computers to a wireless
network
Connects computers to a powerline network
Home-office network
If you have a home office you need strong security. Wireless
routers have a built-in firewall, but software firewalls provide
added security, especially when accessing your network from
remote public hotspots.
Required Components
Device
What it does
Cable/DSL
Connects the internet to Access Point
router
Wireless Access stationary wireless device that sends
Point information to a wireless computer
Wireless adapter Connects computers to a wireless network
Power-line
Connects computers to a power-line network
adapter
Online gaming and entertainment
The best configuration for using streaming audio or video, or
online multi-player gaming, is wired Ethernet, 802.11a, or
802.11g (or dual band).
Required Components
Device
What it does
Cable/DSL
Connects the internet to Access Point
router
Wireless Access stationary wireless device that sends
Point information to a wireless computer
Wireless adapter Connects computers to a wireless network
Power-line
Connects computers to a power-line network
adapter
Digital-media
Connects TVs and stereos to the network
adapter
Hotspot user
Whether you plan to use free public hotspots, or commercial
hotspots (user fees apply), the right gear will make hotspotting
easy. An adapter (PC Card) with a sensitive antenna, an
external antenna connector, or a high-power output are best to
find out which wireless ISPs are available where you are.
Required Components
Device
Wireless notebook
What it does
Connects to Access Points via
adapter
PDA with built-in Wi-Fi or Connects to Access Points via
CompactFlash adapter adapter
Wireless adapter
Range-extending antenna
Connects computers to a wireless
network
Increases the range of wireless
signals
Wireless Internet service For use with remote hotspots
End Notes and Bibliography
(1) Wi-Fi Alliance: Noncertified wireless products have high
failure rates, Bob Brewin; January 13, 2004: Computer World
Magazine.
(2) Wi-Fi Alliance press release February 3, 2004.
Other reference sources:
http://www.wi-fi.org/OpenSection/secure.asp
http://www.wi-fi.org/OpenSection/design.asp
http://milwaukee.about.com/cs/government/a/wifi_p.htm
http://www.siam-wireless.com/wifi-explained.php
http://www.istart.co.nz/index/HM20/PC0/PV21902/EX245/AR2
3995?printable
Wireless gizmos dominate last day of electronics show;
Michelle Kessler and Jefferson Graham. USA TODAY.
McLean, Va.: Jan 12, 2004 (pg. B.02).
Public Wi-Fi networks growing rapidly; Michelle Kessler USA
TODAY.
McLean, Va: June 2, 2003 (page E.11).
Wireless computing: All about Wi-Fi. Consumer Reports, 9/03.
Wi-Fi changes virtually everything; Users say they'll never go
back; Michelle Kessler. USA TODAY. McLean, Va.: Feb. 19,
2004 (page B.01).