CWNA Guide to Wireless LANs, Second Edition
Chapter 1
It’s a Wireless World
At a Glance
Instructor’s Manual Table of Contents

Overview

Objectives

Teaching Tips

Quick Quizzes

Class Discussion Topics

Additional Projects

Additional Resources

Key Terms
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CWNA Guide to Wireless LANs, Second Edition
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Lecture Notes
Overview
In this chapter, the students will first explore how wireless is used in everyday life, and
then take a peek at some popular wireless technologies. They will see how different
sectors of the economy are using wireless technology, and learn about its advantages
and disadvantages.
Chapter Objectives
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Describe how wireless technology is used in daily activities
Tell how wireless local area networks are used in applications such as education,
business, travel, construction, and other areas
Explain the advantages and disadvantages of wireless technology
Teaching Tips
A Day in the Life of a Wireless User
1. Provide an overview of the ways in which wireless technology has embedded itself in
everyday life. Define the term hotspot.
Home
1. Provide an overview of WLANs. Explain how they can increase productivity by
allowing users to connect to a network from a variety of locations without wires.
Mention some example of devices that can be interfaced via wireless networks.
Car
1. Provide an overview of Bluetooth technology, and explain how it is use in small devices
over short distances.
Teaching
Tip
Over 2,000 different computer, telephone, and peripheral vendors have agreed to
create products based on the Bluetooth standard.
Office
1. Discuss the concept of fixed broadband wireless. Explain that it is used to transmit data
wireless between immobile entities, such as office buildings. Briefly mention the
infrastructure, such as antennas, involved in fixed broadband wireless.
2. Introduce the concept of free space optics.
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Teaching
Tip
Atmospheric effects such as scintillation (the "waves of heat" pattern you
sometimes see over dark surfaces) can have an affect on free space optics
transmissions.
Teaching
Tip
With FSO, transmissions fade rapidly in certain kinds of weather—fog, in
particular.
Field
1. Discuss how handheld devices can be used to communicate wirelessly. Explain that
these devices typically connect to the nearest cell tower, which then connect to the local
telephone company.
On Site
1. Describe the purpose and use of RFID tags. Explain the differences between RFID tags
and traditional barcodes.
A Look at Wireless Technologies
1. Provide a brief introduction to wireless technologies.
Wireless Local Area Networks (WLANs)
1. Discuss the characteristics of Wi-Fi. Explain that there are many wireless standards,
each with different characteristics.
2. Discuss the purpose and functionality of wireless NICS. Illustrate with Figure 1-1. If
possible, pass a wireless NIC around to the students.
3. Discuss the purpose and functionality of an Access Point. Illustrate with Figure 1-2. If
possible, pass an access point around to the students.
4. Explain that a patch cable connects an AP to a wired LAN or to the Internet. Discuss
how the interface between a wireless and wired LAN allows wireless users to access
entities on the wired LAN, such as printers. Illustrate with Figure 1-3.
5. Illustrate a home wireless LAN with Figure 1-4.
Bluetooth
1. Provide an overview of Bluetooth technology. Explain the purpose of a radio module
and a link manager.
2. Mention the transmission capabilities of the Bluetooth standard. Illustrate a Bluetooth
device with Figure 1-5. If possible, pass a Bluetooth device around to the students, and
demonstrate a Bluetooth connection.
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3. Explain that when two Bluetooth devices come within range of each other, they
automatically make a connection. Discuss the role of the master and slave(s) in this
connection. Define the term piconet.
Teaching
Tip
Bluetooth is named after the 10th-century Danish King Harald Bluetooth, who
was responsible for unifying Scandinavia.
Teaching
Tip
Bluetooth support is integrated into Microsoft Windows XP Service Pack 2
(SP2).
Telecommunications Links
1. Discuss some of the telecommunication methods in use today.
characteristics of ISDN and T-1 transmission methods.
Explain the
2. Briefly discuss DSL and Cable transmission.
3. Describe the transmission capabilities of WiMax and FOS. Explain that these are lineof-site transmission methods. Discuss the configurations necessary to utilize these
transmission methods, emphasizing the differences between WiMax and FOS. Illustrate
with Figure 1-7.
Cellular Telephony
1. Discuss the characteristics of Global Systems for Mobile (GSM) communications
technology. Stress that information transmitted over GSM may be based on the Wireless
Application Protocol (WAP). Explain that WAP provides a standard way to transmit,
format, and display Internet data for devices like cell phones and handheld devices.
2. Using Figure 1-8 to illustrate, discuss the communication mechanism between
computers and servers when browsing the Internet.
Teaching
Tip
Make sure that the students understand that when a Web server sends a Web
page back to a PC, it is only sending HTML code; the Web browser is
responsible for interpreting that code and displaying the results on the screen.
3. Explain that a WAP cell phone runs a microbrowser that uses Wireless Markup
Language (WML) instead of HTML. Mention that a WAP gateway is used to translate
HTML to WML. Illustrate the WAP model with Figure 1-9.
Radio Frequency Identification (RFID)
1. Describe the difference between RFID tags and standard barcodes in detail.
2. Discuss the transmission characteristics of RFID.
3. Describe the physical characteristics of an RFID tag. Use Figure 1-10 to illustrate.
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Teaching
Tip
No RFID Tag can read through metal.
Teaching
Tip
Different RFID tags operate at different frequency ranges. These frequency
ranges are often used for different applications.
Wireless Technology Categories
1. Using Table 1-1 as a guide, discuss each of the various wireless technology categories.
Mention that WLANs will be the focus of this text.
Quick Quiz 1
1. ____________________ wireless refers to wireless transmissions between devices that
cannot be mobile.
Answer: Fixed broadband
2. ____________________ is an alternative to high-speed fiber optic transmissions.
Answer: Free space optics (FSO)
3. True or False: It is not necessary to connect an AP to a wired LAN or to the Internet.
Answer: False
4. A Bluetooth device uses a(n) ____________________, which is special software that
helps identify other Bluetooth devices, creates the links between the devices, and sends
and receives data.
Answer: link manager
5. ____________________ provides a standard way to transmit, format, and display
Internet data for devices like cell phones and handheld devices.
Answer: Wireless Application Protocol (WAP)
Wireless LAN Applications
1. Explain that wireless LAN applications can be found in every industry with employees
who need the freedom to conduct business without being confined to a specific location.
Education
1. Explain that wireless LANs are an ideal technology for colleges and schools. Discuss
why educational institutions were some of the first organizations to adopt WLANs on a
wide-scale basis.
2. Use Figure 1-11 to illustrate a typical campus map that identifies wireless access points.
CWNA Guide to Wireless LANs, Second Edition
Teaching
Tip
1-6
Some, if not most, of the students may not understand how difficult it was to gain
internet access at educational institutions prior to the adoption of wireless
technology. Try to convey to them what it was like to have to wait for computer
access in the computer lab, and sit in a computer lab for hours on end. Explain
that most dorms at most universities did not even have hard-wired internet access
until the mid-1990s.
3. Stress the ways that wireless technology has reduced the cost of computer at
universities, such as reduced need for wiring and infrastructure.
Business
1. Explain some of the ways that wireless technology has changed how business is
conducted. Stress that the ability to access data to make decisions whenever and
wherever the need arises is critical, and wireless technology facilities easier and quicker
access to data.
2. Explain why and how wireless technologies allow businesses to create an office in a
space where the traditional infrastructure doesn’t exist.
Teaching
Tip
Because WLANs are becoming so widespread, computer giant IBM and cell
phone vendor Nokia are teaming up to make it easier for a company’s employees
to move from a WLAN hotspot to an area of GSM coverage transparently while
remaining connected to the network.
Travel
1. Explain that the travel industry has perhaps adopted wireless technologies more than
any other sector of the economy. Mention the wireless capabilities that have been
installed in most airports and on some airlines.
2. Mention that wireless technology goes beyond serving just the passenger. Explain the
ways that airlines incorporate wireless technology into the everyday tasks inherent to
that industry, such as maintenance.
3. Mention that some airlines are using wireless data transmission to send messages to and
receive message from aircraft in flight.
Construction
1. Discuss the reasons why the construction industry has benefited greatly from wireless
technology, such as ability to quickly reschedule and quick filing of paper work.
2. Explain how wireless technology has been used to create “smart” construction
equipment. Specifically discuss the use of GPS on construction equipment.
Warehouse Management
1. Discuss the importance of proper inventory and knowing the location of items within a
warehouse.
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2. Explain how a WMS coordinates warehouse management activities, and explain how
wireless technology can be used in conjunction with a WMS.
3. Discuss the use of RFID tags on inventory or palettes of inventory. Explain how this
can alleviate or solve many warehouse management issues, and mention how the WMS
manages and coordinates warehouse activities using the RFID tags.
Public Safety
1. Explain how WLAN and GSM technologies are being used in public safety facilities
and equipment. Mention that APs can be installed on municipal building, and can be
used to download large volumes to information to properly equipped public safety
vehicles.
Health Care
1. Provide an overview of the administrative tasks in a medical setting that can be made
easier via wireless technology. Specifically mention the administration of medication.
2. Explain that wireless LAN point-of-care computer systems allow medical staff to access
and update patient records immediately. Discuss the medical administration processes
that can be assisted by wireless technology.
3. Stress that wireless healthcare systems can immediately verify that medication is being
administered to the correct patient in the correct dosage, which eliminates potential
errors and documentation inefficiencies. Mention that the documentation process now
takes place at the bedside where care is delivered, improving accuracy. Also mention
that all hospital personnel now have real-time access to the latest medication and patient
status information.
4. Explain that wireless technology is also used in other medical areas.
example of a video pill. Illustrate with Figure 1-12.
Present the
Wireless Advantages and Disadvantages
1. Explain that with any technology, there are advantages and disadvantages to be
considered, and WLANs are no exception.
Advantages
1. Provide a brief overview of the advantages of wireless LANS.
Mobility
1. Explain that the primary advantage of wireless technology is mobility. Mention that
many occupations that require workers to be mobile.
2. Explain that an increasingly mobile workforce is one characteristic of today’s business
world. Discuss how WLANs fit into this business environment, stressing that with a
wireless network, workers can access information from almost anywhere.
3. Discuss the concept of “flat” organizations. Explain that wireless networks give teambased workers the ability to access the network resources that they need while
collaborating in a team environment.
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Easier and Less Expensive Installation
1. Explain that installing network cabling in older buildings can be difficult and costly.
Discuss the hurdles that might be encountered while trying to outfit a building with a
wired network infrastructure.
2. Stress that the elimination of the need for cabling can substantially reduce the cost of
installing and maintaining a network. Mention how wireless LANs can also reduce the
time cost of installing a network.
3. Mention that wireless networks provide flexibility in terms of setting up and organizing
an office space.
Increased Reliability
1. Discuss the reasons why cable failure may occur, and explain how a wireless LAN can
reduce the likelihood that cable failure would adversely affect a network. Stress that this
increases overall network reliability.
Disaster Recovery
1. Explain that a documented disaster recovery plan is vital to every business if it is to get
back on its feet quickly after a calamity. Define the term hot site, and explain how a hot
site is used in the event of a disaster.
2. Define the term cold site, and discuss the advantages and disadvantages of using a cold
site rather than a hot site. Explain that using a WLAN at a cold site means that very
little cabling is required to get the cold site running.
Teaching
Tip
Typically, a business has an annual contract with a company that offers hot site
services with a monthly service charge. Some services also offer data backup so
that all company data is available regardless of whether a hot site or cold site is
used.
Disadvantages
1. Provide a brief overview of the disadvantages of wireless LANS.
Security
1. Explain that wireless signals are broadcast over open air, making security a major issue.
2. Using the list on pages 20 and 21 of the text as a guide, discuss the unique challenges
inherent to wireless security. Define the terms war driving and rouge access point.
Teaching
Tip
Wireless security will be covered in detail in Chapters 8 and 9.
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Radio Signal Interference
1. Explain that signals from other devices can disrupt wireless transmissions, or the
wireless device may itself be the source of interference for other devices. Discuss the
types of devices that might cause radio signal interference.
2. Explain that the only solution is to this issue is to locate the source of interference and
remove it, or move the wireless access point to a position where the interference will
not occur.
Health Risks
1. Explain that wireless devices emit a low level of RF radiation, as do cell phones.
Mention that high levels of RF radiation are know to cause biological damage, but it is
not know if low level can cause damage as well.
Teaching
Tip
Most wireless devices also emit very low levels of RF energy even when in
stand-by mode. However, these levels are considered non-significant and do not
appear to have health consequences.
Teaching
Tip
Questions have been raised about the safety of hand-held mobile phones with a
built-in antenna positioned close to the user’s head when speaking on the phone.
In mobile devices, the antenna is the primary source of RF. The safety of
cordless phones, which have a base unit connected to the telephone wiring in a
house and which operate at far lower power levels and frequencies, has not been
questioned.
Quick Quiz 2
1. ____________________ institutions were some of the first adopters of WLANs.
Answer: Educational
2. True or False: Wireless technologies also allow businesses to create an office in a space
where the traditional infrastructure doesn’t exist.
Answer: True
3. True or False: The use of wireless technology in a medical setting is limited to medical
administration.
Answer: False
4. A(n) ____________________ is generally run by a commercial disaster recovery
service that allows a business to continue computer and network operations to maintain
business continuity.
Answer: hot site
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5. An employee who purchases an access point and secretly brings it into the office in
order to provide personal wireless access has installed what is known as a(n)
____________________.
Answer: rogue access point
Class Discussion Topics
1. Do any of the students have a wireless LAN installed in their homes? Did they install it
themselves? How did they choose the equipment necessary to install it?
2. Can the students think of any other major industries, other than the ones mentioned in
this chapter, that would benefit from wireless technology?
Additional Projects
1. Beyond the two Wi-Fi hot spot locating tools explored in Projects 1-1 and 1-2, many
other Web sites offer this service. Have the students research online and locate two or
three other such Web sites. Have them perform the same search on the Web site that
they find, Wi-Fi.org, and Yahoo maps. Does one service provide better results than the
others? When the students have completed this assignment, compile their results into a
master list that can be redistributed to the class.
2. Have the students research online to find the typical cost of wireless equipments, such
as wireless NICS and wireless access points. Then, have them research the cost of
regular NICS. How do the per unit costs compare? If wireless equipment is more
expensive, ask the students whether they think this cost is offset by the reduced cost of
cabling.
Additional Resources
1. Wifi411: Online Wi-Fi Hot Spot Locator:
http://www.wifi411.com/
2. WLAN links:
http://wi-fiplanet.webopedia.com/TERM/W/WLAN.html
3. Official Bluetooth Web Site:
http://www.bluetooth.com/
4. FSO White Papers:
http://www.freespaceoptic.com/White_Papers.htm
5. Free Space Optics Primer:
http://www.baselinemag.com/article2/0,1397,1778374,00.asp
6. The Wi-Fi Alliance Home Page:
http://www.wi-fi.org/OpenSection/index.asp
7. WiMAX Forum:
http://www.wimaxforum.org/home
8. Introduction to Cellular and GSM Communications:
http://www.gsmfavorites.com/introduction/
9. WAP Resource Center:
http://www.palowireless.com/wap/
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10. Wireless Markup Language Tutorial:
http://www.computerworld.com/news/2000/story/0,11280,42991,00.html
11. RFID Frequencies Tutorial:
http://www.rfidinc.com/tutorial.html
12. Planes and Trains: Wireless on the Move:
http://www.techworld.com/mobility/features/index.cfm?featureid=512&Page=2&pageP
os=2
13. WLANs Spreading to Hospitals:
http://www.wi-fiplanet.com/news/article.php/1581811
Key Terms
 Access point (AP): A wireless device that acts as a base station to receive signals from
and transmit signals to wireless network interface cards in other wireless devices.
 Bluetooth: A low-power wireless data and voice transmission technology.
 Cable modem: A telecommunications technology that sends data over television cable.
 Cold site: A remote site that provides only office space in the event of a disaster.
 Digital subscriber lines (DSL): A telecommunication technology that uses telephone
lines.
 Fixed broadband wireless: A wireless wide area network technology for transmissions
between buildings.
 Free space optics (FSO): A fixed broadband wireless technology that uses lowpowered infrared beams and transmits at speeds up to 1.25 Gbps over a distance of up
to 6.4 kilometers (4 miles). An alternative to high-speed fiber optic transmissions.
 Gbps: Billions of bits (gigabits) per second.
 Global Systems for Mobile (GSM) communications: A wireless wide area network
technology used by cellular telephones and handheld devices.
 Hot site: A remote site that contains redundant equipment, supplies, and
telecommunications infrastructure for a business, and is ready immediately in the event
of a disaster.
 Hotspot: Location where wireless data service is available.
 Integrated Services Digital Networks (ISDN): A wide area network technology that
transmits at 256 Kbps.
 Kbps: Thousands of bits (kilobits) per second.
 Link manager: Bluetooth software that helps identify other Bluetooth devices, creates
the links with them, and sends and receives data.
 Master: A Bluetooth device that controls wireless traffic.
 Mbps: Millions of bits (megabits) per second.
 Microbrowser: A small browser program that runs on a cellular telephone or a
handheld device.
 Piconet: A Bluetooth network that contains one master and at least one slave.
 Radio frequency identification (RFID): Small tags that function like electronic
barcodes.
 Radio module: Bluetooth radio transceiver built onto a microprocessor chip.
 Rogue access point: A WLAN access point installed without permission.
 Slave: A Bluetooth device that takes commands from the master device.
 T-1: A wide area network technology that transmits at 1.544 Mbps.
 WAP gateway: A device that translates between WML and HTML.
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WAP proxy: Same as WAP gateway.
War driving: Driving around with a wireless device searching for a wireless signal.
Wi-Fi (Wireless Fidelity): Another name for a wireless local area network.
WiMax: A fixed broadband wireless technology that sends and receives signals
between antennas over longer distances.
Wireless adapter: Another name for a wireless network interface card (NIC).
Wireless Application Protocol (WAP): A standard way to transmit, format, and
display Internet data for devices like cell phones or handheld devices.
Wireless local area network (WLAN): A local area network (LAN) in which the
devices are not connected by wires.
Wireless Markup Language (WML): A programming language designed to display
text-based Web content on the small screen of a cell phone or handheld device.
Wireless network interface card (wireless NIC): A card that is inserted into a device
that enables it to communicate on a wireless network.
Wireless personal area network (WPAN): Wireless technologies that have a limited
transmission range of up to 3.3 meters (10 feet).
Wireless wide area network (WWAN): Wireless technologies that have a
transmission range from 152 meters (500 feet) to 120 kilometers (75 miles) or more.