Guide to this Instructor’s Manual

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New Perspectives on Computer Concepts 2011 Instructor’s Manual of

Computer Concepts

Chapter Five: LANs and WLANs

A Guide to this Instructor’s Manual:

We have designed this Instructor’s Manual to supplement and enhance your teaching experience through classroom activities and a cohesive chapter summary.
This document is organized chronologically, using the same heading in blue that you see in the textbook. Under each heading you will find (in order): Lecture Notes that summarize the section, Figures and Boxes found in the section (if any), Teacher Tips, Classroom Activities, and Lab Activities. Pay special attention to teaching tips, and activities geared towards quizzing your students, enhancing their critical thinking skills, and encouraging experimentation within the software.
In addition to this Instructor’s Manual, our Instructor’s Resources CD also contains PowerPoint Presentations, Test Banks, and other supplements to aid in your teaching experience.
For your students:

Our latest online feature, CourseCasts, is a library of weekly podcasts designed to keep your students up to date with the latest in technology news. Direct your students to, where they can download the most recent CourseCast onto their mp3 player. Ken Baldauf, host of CourseCasts, is a faculty member of the Florida State University Computer Science Department, where he is responsible for teaching technology classes to thousands of FSU students each year. Ken is an expert in the latest technology and sorts through and aggregates the most pertinent news and information for CourseCasts so your students can spend their time enjoying technology, rather than trying to figure it out. Open or close your lecture with a discussion based on the latest CourseCast.

Table of Contents

Chapter Objectives


Section A: Network Building Blocks


Section B: Wired Networks


Section C: Wireless Networks


Section D: Using LANs


Section E: Security Through Encryption


Glossary of Key Terms


Chapter Objectives

Students will have mastered the material in Chapter Five when they can answer the following questions:

  • What are PANs, LANs, MANs, and WANs?

  • Which devices are most common on LANs?

  • On a network, how does file sharing mode differ from client/server mode?

  • Why do networks have different topologies?

  • What is the purpose of a communications protocol?

  • Why do most networks transmit digital rather than analog signals?

  • How does data find its way over a network to a specified destination?

  • Is it easy to set up wired and wireless networks?

  • Are there different kinds of wired and wireless LANs?

  • What are the advantages and disadvantages of LANs?

  • What makes a network a security risk and how can networks be secured?

  • How does encryption work?


050100 In a network, a server is a computer that provides services to other computers called peers. (Answer: False) (249)

050200 Star, ring, and mesh are examples of network topologies. (Answer: True) (250)

050300 When you send an e-mail message over a network, it is chopped up into packets. (Answer: True) (253)

050400 The IP address assigned to your computer on the Internet is derived from your computer’s MAC address. (Answer: False) (255)

050500 Some network technologies use home telephone or electric cabling for computer networks. (Answer: True) (257)

050600 The most popular type of wired network is Ethernet. (Answer: True) (258)

050700 Network speeds are measured in megabytes and gigabytes. (Answer: False) (261)

050800 Many wireless networks use radio waves to transmit data. (Answer: True) (265)

050900 Bluetooth is a wireless technology used for WANs. (Answer: False) (267)

051000 A wireless infrastructure network uses a centralized broadcasting device, such as a wireless access point or router. (Answer: True) (270)

051100 Wireless networks are less secure than wired networks. (Answer: True) (273)

051200 WEP, WPA, and PSK are examples of Wi-Fi networks. (Answer: False) (283)

051300 Public key encryption uses a public key to encrypt messages, but a private key is required to decrypt messages. (Answer: True) (286)



052100 Networks come in many sizes and use many different technologies, yet they all need to communicate with each other. What is the key to network intercommunication?

  1. Packet switching

  2. Network protocols

  3. Network topology

  4. Peer-to-peer technology

(Answer: b)

Network Classifications (246)


  • Stress that early PCs were designed for solo use, yet the advantages of networking were identified as early as 1976.

  • Discuss shared resources as an identifiable advantage of networking. Ask students to list the benefits and drawbacks of shared resources and information.

  • Describe the different geographic scopes for networks. Which of these are familiar to students? Why is it important (or convenient) to describe networks in terms of their scope?


Point out what type of network(s) your school uses. If there is one network type used, explain why it was considered the best choice to meet the school’s needs. If your school has a variety of networks of different types, explain why the school has this mix of networks.

  • Refer students to the New Perspectives Web site for a Student Edition Lab called “Networking Basics.”


  • Figure 5-1, Figure 5-2


  • Class Discussion: Networks have changed the way we communicate and share resources in a number of ways. Ask students to list examples from their own lives.

  • Group Activity: Divide students into two groups. Ask each group to come up with a scenario in which each type of network (PAN, LAN, MAN, or WAN) is most appropriate. Have each group take turns in sharing a scenario from their group list and write it on a whiteboard.

  • Quick Quiz:

  1. What type of network are you most likely to encounter in a school lab or small business setting? (Answer: LAN)

  2. How can computer networks be classified? (Answer: According to their geographic scope, mode, and/or physical topology.)

LAN Standards (247)


  • Discuss possible repercussions of the diversity of LAN technologies that previously existed.

  • Discuss the advantages that exist in the consolidation around Ethernet technology and Wi-Fi standards.

Network Devices (248)


  • Point out that when students use a computer in the library to print a document or access the Internet, they are using a LAN.

  • Note that in many cases, using a LAN is transparent.

  • Discuss the role of network interface cards and “built-in networking” circuitry as providing the means to connect nodes to a network.

  • Discuss the role of network devices, such as hubs, switches, routers, gateways, bridges and repeaters, in supporting the network.


Point out the different peripherals and computers that are networked in the classroom.

  • Figure 5-3


  • Class Discussion: Ask students about their experiences using a LAN. Point out that they very likely have used a LAN, in places like libraries, coffee shops and school labs, and been unaware of it.

  • Quick Quiz:

  1. A(n) ___________ is any device that contains network circuitry to directly connect to a network. (Answer: networked peripheral)

  2. A(n) ___________ is any electronic device that broadcasts network data, boosts signals, or routes data to its destination. (Answer: network device)

Clients, Servers, and Peers (249)


  • Discuss the difference between peer-to-peer mode and client/server mode.

  • Use Figures 5-4 and 5-5 to illustrate the difference between client/server and peer-to-peer networking.

  • Explain what kind of mode your school network(s) use(s).


  • Figure 5-4, Figure 5-5


  • Assign a Project: Ask students to create simple sketches of client/server and peer-to-peer modes that include different types of nodes and networked peripherals.

  • Quick Quiz:

  1. A(n) ___________ stores files and supplies them to workstations on request. (Answer: file server)

  2. A(n) ___________ handles jobs sent to network printers. (Answer: print server)

  3. A(n) ___________ runs application software for network workstations. (Answer: application server)

Physical Topology (250)


  • Review the different types of topologies and the advantages and disadvantages of each. For example, a bus topology allows quick and cost-efficient communication of one signal to many users.

  • Discuss the most common uses of different topologies. For example, star topologies are often used with telephone lines, bus topologies with cable lines, and tree topologies with larger LANs found in schools and businesses.

  • Use Figure 5-6 to describe the major topologies.

  • Describe how gateways can connect networks to one another, even those with different topologies.

  • Discuss how a bridge is used to connect similar networks.


Consider using the board to draw a series of interconnected networks using colors to differentiate between nodes and gateways.

  • Figure 5-6


  • Assign a Project: Ask students to create a chart that includes simple sketches of the five network topologies (star, ring, bus, mesh, and tree) and the advantages and disadvantages of each.

  • Quick Quiz:

  1. The arrangement of devices in a network is called its ___________. (Answer: physical topology)

  2. Data traveling in a(n) ___________ network can take any of several possible paths from its source to its destination. (Answer: mesh)

  3. True/False: You can connect various types of networks. (Answer: True)

Network Links (251)


  • Discuss the role of the communications channel in providing a pathway between network devices.

  • Explain the difference between physical and wireless communication links.

  • Note that all networks, whatever their geographic scope, organizational mode or physical topology, rely on some form of link.

  • Discuss the difference between physical (cable-based) links and wireless links (RF waves, microwaves, infrared light waves).

  • Define bandwidth, using the highway example given in the book.


Discuss the bandwidths of the various forms of connections like twisted-pair cable, coaxial cable, fiber-optic cable, radio waves, infrared light, etc. Bring in examples of physical cables.

  • Figure 5-7


  • Quick Quiz:

  1. A(n) ___________ provides a pathway for signal transmissions. (Answer: communications channel or link)

  2. __________ is the transmission capacity of a communications channel. (Answer: Bandwidth)

  3. True/False: High-bandwidth communications systems are sometimes referred to as broadband. (Answer: True)

Communications Protocols (252)


  • Define a protocol as a set of rules that describe how parties should communicate.

  • Describe what a communications protocol does, including dividing messages into packets, addressing packets, initiating and regulating the flow of transmission, checking for transmission errors, acknowledging receipt of transmitted data, etc.

  • Define the term "packet" and identify the parts of a packet.

  • Explain the process of packet switching and why this technique is used.

  • Make sure students understand the difference between a circuit switching network (the telephone system) and a packet switching system (the Internet, and local area networks).

  • Discuss the two most commonly used network addresses: the MAC address and the IP address.


It might be helpful to students’ understanding to compare protocols to spoken language. In order for two people to communicate, they must share a common language. If one person speaks only Danish and the other only Hebrew, they won’t be able to communicate. But if both also speak English, they could agree to use that as a common language. Likewise, networks must agree on a common language. Note that the language, or protocol, of the Internet is TCP/IP. While many networks use other communication protocols, they must also be able to “speak” TCP/IP in order to communicate over the Internet.

  • Figure 5-8, Figure 5-9, Figure 5-10, Figure 5-11


  • Group Activity: Break students up into small groups. Give each group a simple multi-page letter and a few unaddressed envelopes. Have them create packets. Stress that each packet must include sender and recipient addresses, part of the message (‘data’), and sequence information (page number). Use one set of packets to illustrate how the message is sent across the Internet and reassembled at the destination once all packets have been received.

  • Quick Quiz:

  1. What are three aspects of network communications that communications protocols are responsible for? (Answers: Setting standards for formatting (encoding and decoding) data, guiding data to its destination, and mitigating the effects of interference)

  2. True/False: Handshaking refers to the process through which two computers on a network negotiate their communications protocols. (Answer: True)



052200 Suppose you’re setting up a network in your home or apartment. You want all of the computers to access the cable modem that provides Internet access. What is the one additional component that you should purchase to tie the network together?

  1. A router

  2. A network interface card

  3. A file server

  4. A HomePlug Ethernet port

(Answer: a)

Wired Network Basics (256)


  • Discuss the advantages and disadvantages of a wired network.

  • Explain that some wired networks technologies use communications channels that already may exist in homes.

  • Discuss the advantages and disadvantages of wired networks.

  • Mention that the most popular LAN technology today is Ethernet.


  • Figure 5-12


  • Class Discussion: Ask students if they have a wired home area network. What do they like about it? What do they dislike?

HomePNA and Powerline Networks (257)


  • Explain that HomePNA is a network technology that utilizes existing telephone wires and coaxial cables to provide a communications channel between network devices.

  • Review how HomePNA compares to Ethernet.

  • Explain that a powerline network is a network technology that utilizes electrical wiring to provide a communications channel between network devices.


  • Figure 5-13, Figure 5-14


  • Class Discussion: The text mentions that some hotels have retrofitted their guest rooms to provide Internet access via a HomePNA. Ask students to think of similar situations where this strategy might work.

  • Quick Quiz:

  1. True/False: HomePNA is faster than Ethernet. (Answer: False)

  2. A(n) _______ network uses premises electrical wiring to form the infrastructure for a LAN. (Answer: powerline)

Ethernet (258)


  • Explain that Ethernet is the leading LAN technology in use today.

  • Describe how Ethernet simultaneously broadcasts data packets to all network devices.

  • Discuss what happens when packets collide, the speed at which packets travel, and what sort of cables and topology the network uses.

  • Use Figures 5-15, 5-16, and 5-17 to discuss the specifics of Ethernet and its requirements.

  • Discuss how the term Ethernet actually refers to the IEEE 802.3 family of standards.


Review the reasons for the success of the Ethernet standard, as listed on page 259. Ask students which, if any, of these reasons stands out for them as the main reason why Ethernet became so popular.

  • Figure 5-15, Figure 5-16, Figure 5-17


  • Assign a Project: Have students list at least two reasons Ethernet is so popular. Can they come up with any reasons in addition to those listed on page 259?

  • Quick Quiz:

  1. Today, most personal computers and LAN equipment work with ______________ Ethernet. (Answer: Gigabit)

  2. True/False: Ethernet simultaneously broadcasts data packets to all network devices. (Answer: True)

  3. What does CSMA/CD stand for? (Answer: Carrier Sense Multiple Access with Collision Detection)

Ethernet Equipment (260)


  • Discuss that, in order to connect to an Ethernet network, a computer must have supporting hardware installed.

  • Explain that the computer can be Ethernet ready, which means it contains built-in Ethernet hardware (including an Ethernet port). If it is not Ethernet ready, then an Ethernet adapter (Ethercard or NIC) can be installed in one of three ways: via a USB port, a PC slot, or a PCI slot on the system board.

  • Explain that the network adapter usually is connected by cable to a device called a network device (like a hub, switch or router).

  • Explain the differences between hubs, switches and routers.

  • Stress that the components of the Ethernet network (the Ethernet adapters and network devices) should all be chosen to work together efficiently.


If you have a network card that is not in use, bring it to class as a visual aid. Ask your tech support department if they have any "dead" network cards you could have. Other network devices, such as hubs, switches and routers, could also be used as visual aids. If possible bring a Cat 5 or Cat 6 cable with an RJ45 connector on one end.

  • Figure 5-18, Figure 5-19, Figure 5-20, Figure 5-21


  • Assign a Project: Have students list the network hardware needed for a typical home network that will be used to access the Internet.

  • Quick Quiz:

  1. True/False: A network switch is a sophisticated connection device that sends data only to the devices specified as the destination. (Answer: True)

  2. What type of network device ships data from one network to another? (Answer: network router)

  3. True/False: Using a hub instead of a switch can increase a network’s performance and security. (Answer: False)

Ethernet Setup (262)


  • Ask students whether they have set up a wired home network. Was it easy or difficult to set up?

  • Explain how to set up a wired Ethernet home area network.

  • Refer to the photographs in Figure 5-23.


Demonstrate how to make folders and drives available to others when using Windows.

  • Figure 5-22, Figure 5-23, Figure 5-24


The New Perspectives Lab “Local Area Networks” deals with issues that relate to this section of the textbook. You might want to go through the lab during class time if you have a computer with a projection device. Otherwise, assign this lab for students to do outside of class.

  • Class Discussion: If your classroom has a computer that is connected to a campus network, allow the class to examine the connections. Is it a wired or wireless connection? If it is wired, what kind of cable is used? Can you identify the type of network device the computer is connected to (a hub, switch, or something else)? If the connection is wireless, where is the wireless hub? If necessary, take a field trip to the hub to see what it looks like. If your building has a cable room (or closet) where network connections come together, arrange a visit to that room as well.

  • Quick Quiz:

  1. Ethernet network cables are terminated at each end with plastic _______________ connectors. (Answer: RJ45)

  2. True/False: To prevent unauthorized changes to your network, it is essential that you change the router’s password. (Answer: True)



052300 When you’re setting up a wireless network, you see an option asking if you want to broadcast the network SSID. You should:

  1. Change the default SSID and broadcast it while you set up the network.

  2. Turn SSID broadcasting off so that hackers don’t know the network’s encryption key.

  3. Make sure SSID is broadcasting so that your network is protected by strong encryption.

  4. Activate SSID broadcasting or else the network devices won’t be able to send data to the router.

(Answer: a)

Wireless Basics (265)


  • Discuss how networks of all sizes (PANs, LANs, and WANs) can use wireless technologies.

  • Use the following chart to discuss the advantages and disadvantages of various types of wireless network links:

    Communications Link



    Radio waves

    Longer range; does not require line-of-sight transmission

    Before you can use a frequency for communication, it must be licensed from the FCC

    Infrared transmissions

    An FCC license is not required

    Short transmission range; requires line-of-sight transmission

    Microwave transmissions

    Long range; can be aimed in one direction; has higher capacity when compared to radio waves

    Microwaves cannot penetrate metal; requires line-of-sight transmission; microwave stations cannot be more than 25 or 30 miles apart

    Satellite links

    A GEO satellite provides continuous coverage over a particular area; an LEO satellite offers transmission delays of only a few hundredths of a second

    A GEO satellite requires a delay of 24 seconds to transmit data; an LEO satellite requires a web of satellites

  • List the advantages and disadvantages of wireless networks.

  • Explain that Wi-Fi specifies the hardware, the type of transmission medium, and the transmission speed.


  • Figure 5-25, Figure 5-26


Most students will be familiar with the use of radio waves for data communication. Students also may be familiar with satellite transmission if they have used a GPS system. However, many will not be familiar with the use of infrared transmissions, even though they use some infrared devices, such as television remote controls. Discuss examples of each of these technologies.

  • Class Discussion: If your building has a wireless network, ask the class if they use it. Is it reliable?

  • Quick Quiz:

  1. Most wireless networks transport data using which type of signal? (Answer: RF)

  2. True/False: Infrared light can be used to carry data signals, but only for short distances and between devices with clear line of sight. (Answer: True)

  3. True/False: Workstations, peripheral devices, and network devices can be equipped with transceivers to send and receive data on wireless networks. (Answer: True)

Bluetooth (267)


  • Explain that the name Bluetooth is derived from the nickname of a 10th century Danish king, Harold Bluetooth. According to the inventors of the Bluetooth technology, the king engaged in diplomacy that led warring parties to negotiate with each other, making Bluetooth a fitting name for this technology, which allows different devices to talk to each other.

  • Discuss how Bluetooth technology allows Bluetooth devices to form networks automatically when they come within range of each other.

  • Discuss the term Bluejacking as it relates to one Bluetooth device sending a message to another Bluetooth device anonymously when they are within range of each other.

  • Refer to Figure 5-28. Ask students whether there are other uses, beyond the wireless headset that clips to a motorcycle helmet, that they can envision for Bluetooth technology.


Ask if any students have any Bluetooth devices with them in class. If so, have them show the devices to the class.

  • Figure 5-27, Figure 5-28


  • Class Discussion: Ask students to list as many Bluetooth devices as they can think of. Write them down on a whiteboard.

  • Quick Quiz:

    1. What is another name for a Bluetooth network? (Answer: piconet)

    2. True/False: Bluetooth is typically used to connect a collection of workstations. (Answer: False)

    3. True/False: Bluetooth networks form automatically when Bluetooth devices are within range of each other. (Answer: True)

Wi-Fi (268)


  • Stress that Wi-Fi is a term used for a family of wireless standards know as IEEE 802.11.

  • Note that some of the standards are cross compatible and some are not, as noted in the table in Figure 5-29.

  • Emphasize that the maximums listed in the table in Figure 5-29 are theoretical maximums because of the obstacles that wireless signals face in the typical network environment (an office, for example).


  • Figure 5-29, Figure 5-30

Wi-Fi Equipment (268)


  • Compare the equipment needed for a wired LAN with the equipment needed for a Wi-Fi LAN.

  • Point out that most computers today come equipped with Wi-Fi circuitry.

  • Discuss the different types of W-FI adapters.

  • Survey students about the wireless capability of their own computers. Do their desktop computers have a Wi-Fi card or did they come pre-equipped with wireless capabilities? What capabilities do their laptops have?

  • Discuss the advantages of a wireless ad-hoc network over a wireless infrastructure network. Present real-world scenarios to students that require one kind of solution or the other and ask them to identify which type of network would be preferred, and why.


  • Figure 5-31, Figure 5-32, Figure 5-33, Figure 5-34


  • Class Discussion: Ask student what Wi-Fi equipment they own. Have them refer to Figure 5-31 for ideas if they are unsure.

  • Quick Quiz:

    1. True/False: All wireless networks require a router. (Answer: False)

    2. A(n) _______ is a wireless access point that also includes routing circuitry that can connect a Wi-Fi network to the Internet. (Answer: wireless router)

Wi-Fi Setup (270)


  • Present the basic procedure for setting up a wireless network.

  • Discuss basic security options (changing router’s default password, changing the default SSID, and enabling encryption).

  • Explain SSID. Note that an extremely weak form of wireless network security is to turn off the broadcast of the SSID. While to the average user there does not appear to be a network in use, a network protected in this way is still easily accessed by crackers using the appropriate tools.

  • Explain that forms of encryption and authentication should also be used (at a minimum WEP but preferably WPA).

  • Note that some newer wireless access points disable the automatic SSID broadcast feature in an attempt to improve network security.

  • Note that some advanced wireless access points support broadcasting multiple SSIDs, allowing the creation of Virtual Access Points. This partitions a single physical access point into several logical access points, each of which can have a different set of security and network settings.


Explain, or if possible, demonstrate the Wi-Fi setup at your school. Consider inviting someone from the IT department to come and further explain the setup to the class.

  • Figure 5-35, Figure 5-36, Figure 5-37, Figure 5-38


Refer students to the New Perspectives Web site for a Student Edition Lab called “Wireless Networking.”

  • Class Discussion: What are some advantages and disadvantages of wireless networks? Is the connection always available? Do the advantages outweigh the disadvantages with regard to this technology? Is the answer contingent on circumstances? If so, list some of them.

  • Quick Quiz:

  1. ______ technology uses two or more antennae to essentially send multiple sets of signals between network devices and is used to improve Wi-Fi speed and range. (Answer: MIMO or multiple-input multiple-output)

  2. True/False: Microwaves can be aimed in a single direction and have more carrying capacity than radio waves. (Answer: True)

  3. The IEEE 802.11 family of standards is also known as ______.

  1. MIMO

  2. SSID

  3. Wi-Fi

  4. Bluetooth

(Answer: c.)



052400 There are many ways to share files among the computers on a network. Which one of the following is the LEAST secure way to share files?

  1. Use a file server.

  2. Activate file sharing for the root directory of all the computers in the network.

  3. Designate specific folders on your computer as shared.

  4. Put files you want to share in the Public folder.

(Answer: b)

LAN Advantages and Challenges (274)


  • Review the advantages alongside the challenges listed in the text.

  • Refer to Figure 5-40 to point out the devices that can be used on a LAN.


  • Figure 5-39, Figure 5-40


  • Class Discussion: Ask whether students have experienced any of the benefits listed in the text (such as shared hardware, shared software, increased productivity). Discuss whether students have experienced any of the disadvantages listed in the text (such as network malfunctions, wireless LAN ‘snooping,’ malicious code received via a network connection).

  • Quick Quiz:

    1. Hardware, software, and data accessible to authorized network users are called _____. (Answer: shared resources)

    2. True/False: Sharing networked hardware can reduce costs. (Answer: True)

    3. True/False: LANs are more vulnerable than standalone computers to malicious code. (Answer: True)

Sharing Files (276)


  • Discuss file servers for use on home networks. As the costs of file servers decline, and the number of computers in a single home continues to rise, file servers for home use can be something to consider.

  • Explain that a blade server is a circuit board containing a processor, memory and a network connection designed to slide into a blade server unit. Discuss why businesses use blade server units (cost effective, energy efficient, flexible).

  • Students may well be able to relate to having had a file exclusively on their laptop, for example, when the laptop failed; having had a file server at home that made backup as easy as dragging and dropping a file could have saved a significant hassle.


Remind students that it’s not a good idea to allow shared access to the root directory (usually drive C) on their computers.

  • Figure 5-41, Figure 5-42, Figure 5-43, Figure 5-44


  • Assign a Project: Have students look for and identify the shared resources available on networked classroom or lab computers.

  • Quick Quiz:

  1. ____________ assigns a drive letter to a storage device located on a network workstation. (Answer: Drive mapping)

  2. A(n) __________ is a computer whose primary purpose is to be a repository for files that can be accessed by network workstations. (Answer: file server)

  3. True/False: You can limit access to viewing only in folders you’ve designated as shared. (Answer: True)

Sharing Printers (278)


  • Use Figure 5-45 to consider the different ways in which a printer can be attached to a LAN.

  • Use Figure 5-46 to talk about the options in the printer dialog box that permit the sharing of this resource across the network.


  • Figure 5-45, Figure 5-46, Figure 5-47

LAN Parties (280)


  • Note that a controversy among those in the LAN party community is advertising at LAN parties; some events have gained a reputation as an advertising front for companies (e.g., Bawls, Alienware) in order to generate sales or demonstrate their products to the gaming audience. However, many large-scale LAN parties actively seek sponsorship in order to reduce operating risks to the organizers and to provide prizes for attendees.

  • Note that LAN party attendees tend to be more experienced gamers as the setup required makes LAN parties too much of a commitment for casual players.


  • Figure 5-48


  • Class Discussion: Do any students have experience with LAN parties? If so, in what context? How many people were in attendance? Have them describe their experiences.

  • Assign a Project: What kinds of LAN parties are open to gamers in the area where you are located? Ask students to use the Internet to find the Web site(s) of LAN parties in the area and learn about what is involved and what software/hardware is required for participation. How much does it cost to be a part of the event?

Troubleshooting (280)


  • Discuss which of the problems listed on page 281 are most common. Discuss other problems not included in this list.


Demonstrate how Windows tools can be used to troubleshoot network problems.

  • Figure 5-49


  • Assign a Project: Have students investigate troubleshooting resources available at their school or campus. Is there a Help Desk available via the telephone or email? Are there resource discs or a campus Web page with troubleshooting utility freeware software?

  • Quick Quiz:

    1. True/False: Network computers are vulnerable to unauthorized access from many sources and locations. (Answer: True)

    2. For security reasons, it is not advisable to allow shared access to the __________ directory of drive C on your computer.

    1. root

    2. home

    3. network

    4. shared

(Answer: a.)



052500 As part of the process of setting up a wired network what should you remember to do?

  1. Assign an IP address to each network device.

  2. Remove the Ethernet card from any computer that has one.

  3. Enable wireless security.

  4. Disable the SSID.

(Answer: c)

Wi-Fi Security (282)


  • Discuss LAN jacking. When the laptop's wireless adapter (NIC) is set to promiscuous mode, it will receive any packets within its range. The goal is to find vulnerable sites either to obtain free Internet service or to potentially gain illegal access to the organization's data.

  • Note that the legality of war driving in the United States is not clearly defined at this point. There has never been a conviction for war driving, and there is the untested argument that the 802.11 and DHCP protocols operate on behalf of the owner giving consent to use the network, but not if the user has reason to know that there is no consent.

  • Discuss the options for securing a wireless network.


  • Figure 5-50, Figure 5-51, Figure 5-52


  • Assign a Project: Give students a list of basic networking terms and ask them to create a personal glossary. Encourage students to investigate terms that they cannot clearly define.

  • Quick Quiz:

  1. ____________ is another name for LAN jacking. (Answer: War driving)

  2. ____________ scrambles the data transmitted between wireless devices and then unscrambles the data only on devices that have a valid encryption key. (Answer: Wireless encryption)

  3. True/False: All devices on a network must use the same type of encryption. (Answer: True)

Encryption (285)


  • Discuss why it is important to encrypt sensitive data that will be transmitted over a network.

  • Use the code in Figure 5-53 as an example of weak encryption. Discuss the flaws of this technique and the ways in which a code has to be changed in order to be considered strong encryption.


A good analogy for explaining public key encryption (PKE) is that of a locked front door to a building, and the door has a mail slot. The mail slot is exposed and accessible to the public; its location (the street address) is analogous to the public key. Anyone knowing the street address can go to the door and drop a written message through the slot. However, only the person who possesses the matching private key, the owner of the building in this example, can open the door and read the message.

  • Figure 5-53, Figure 5-54, Figure 5-55, Figure 5-56


  • Assign a Project: History abounds with fascinating stories about encryption and cryptography. Governments and militaries have long used encryption to ensure the secrecy of their communications. One notable example is the Enigma cipher machine used by the German military during World War II. Ask students to use the Internet to read about the Enigma machine and the role that it played in German dominance early in the war. How did the machine work to encrypt the messages of the German military?

  • Quick Quiz:

  1. _________ key encryption uses the same key to encrypt the message as to decrypt it. (Answer: Symmetric)

  2. A(n) __________ is a procedure for encrypting or decrypting a message. (Answer: cryptographic algorithm)


053100 Have you ever accessed a free WLAN?

a. Yes

b. No

c. Not sure

053200 Do you believe that rogue WLANs can survive alongside for-profit broadband ISPs?

a. Yes

b. No

c. Not sure

053300 Are broadband providers justified in limiting the terms of their service agreements to “one subscription, one customer”?

a. Yes

b. No

c. Not sure

Glossary of Key Terms

  • AES, 285

  • Application server, 249

  • Bandwidth, 251

  • Bluetooth, 267

  • Bridge, 250

  • Broadband, 251

  • Bus topology, 250

  • Ciphertext, 285

  • Circuit switching, 253

  • Client/server mode, 249

  • Communications channel, 251

  • Communications protocol, 252

  • Cryptographic algorithm, 285

  • Cryptographic key, 285

  • CSMA/CD, 259

  • Decryption, 285

  • DHCP, 255

  • Drive mapping, 276

  • Encryption, 285

  • Ethernet, 258

  • Ethernet adapter, 261

  • File server, 249

  • Gateway, 251

  • Handshaking, 252

  • HomePNA, 257

  • Infrared light, 265

  • IP address, 255

  • LAN, 247

  • LAN jacking, 282

  • LAN party, 280

  • MAC address, 254

  • MAN, 247

  • Mesh topology, 250

  • Microwaves, 265

  • MIMO, 268

  • Narrowband, 251

  • Network attached storage, 248

  • Network device, 248

  • Network hub, 261

  • Network interface card, 248

  • Network router, 261

  • Network switch, 261

  • Networked peripheral, 248

  • Node, 248

  • Octet, 255

  • Packet, 253

  • Packet switching, 253

  • PAN, 246

  • Peer-to-peer mode, 249

  • PGP, 287

  • Physical topology, 250

  • Piconet, 267

  • Plaintext, 285

  • Powerline network, 258

  • Print server, 249

  • PSK, 283

  • Public key encryption, 286

  • RF signals, 265

  • Ring topology, 250

  • RJ45 connector, 262

  • Shared resources, 274

  • SSID, 272

  • Star topology, 250

  • Strong encryption, 285

  • Symmetric key encryption, 286

  • Transceiver, 265

  • Tree topology, 250

  • WAN, 247

  • Weak encryption, 285

  • WEP, 283

  • Wi-Fi, 268

  • Wi-Fi adapter, 269

  • Wired network, 256

  • Wireless access point, 270

  • Wireless ad-hoc network, 270

  • Wireless encryption, 283

  • Wireless infrastructure network, 270

  • Wireless network, 265

  • Wireless network key, 284

  • Wireless router, 270

  • WPA, 283

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