Download THE ROLES AND GOALS OF INFORMATION TECHNOLOGY

EXTENDED LEARNING MODULE D
NETWORK BASICS
THE MODULE IN SHORT FORM…
This module is a basic introduction to networks and their components. You’ll start out with the most simple
types of networks and go on to the Internet, client/server systems, and then cover some network
technologies.
The first section describes peer-to-peer networks and what would be needed to set up a small network at
home or in a dorm room. There are two possibilities for building a home network: (1) with Ethernet cards
and network cabling or (2) using existing phone wiring. This section also covers adding wireless access to
the home network. This section includes key terms such as peer-to-peer networks, network interface
card, Ethernet card, router, Bluetooth, WiFi, and router.
The second section discusses the five ways of accessing the Internet
1. Telephone or dial-up connection (key terms such as telephone modem)
2. Digital Subscriber Line (DSL)
3. Cable modem (key terms such as cable modem)
4. Internet over satellite
5. Wireless Internet connection (key terms such as Palm OS, Pocket PC OS, Wireless Internet service
provider, and personal digital assistant)
The third section deals with client/server networks, first from a business viewpoint and then briefly from the
point of view of physical components including key terms such as client/server network and
communications protocol.
The next section covers
 the classification of networks by geographical distance (key terms such as local area network,
municipal area network and wide area network)
 wired telecommunications media (key terms such as coax and optical fibre)
 wireless telecommunications media (key terms such as infrared, microwave, repeater, and
communications satellite).
The last section discusses communications service providers and the ownership options that are available.
STUDENT LEARNING OUTCOMES
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6.
Identify and describe the four basic concepts on which networks are built.
List the components you need to set up a small peer-to-peer network at home.
Compare and contrast the various Internet connection possibilities.
Describe client/server business networks from a business and physical point of view.
Define local area networks (LANs), municipal area networks (MANs), and wide area networks (WANs).
Compare and contrast the types of communications media.
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EXTENDED LEARNING MODULE D
LECTURE OUTLINE
INTRODUCTION (p. 426)
1. Basic Principles of Networks
PEER-TO-PEER HOME NETWORK (p. 427)
1. Home Network Components
2. Wireless Access to Your Home Network
3. Home Network with Existing Home Wiring
INTERNET ACCESS (p. 431)
1. Telephone or Dial-Up Connection
2. Digital Subscriber Line (DSL)
3. Cable Modem
4. Internet over Satellite
5. Internet Access on Multiple Computers
6. Wireless Internet Connection
BUSINESS NETWORKS (p. 435)
1. Client/Server: A Business View
2. Client/Server: A Physical View
LANs, MANs, WANs, AND COMMUNICATIONS MEDIA (p. 441)
1. Classification of Networks by Geographic Distance
2. Telecommunications Media: The Paths That Carry Information
3. Bandwidth
4. Wired Communications Media
5. Wireless Communications Media
6. Infrared and Omnidirectional Microwave for Short Distances
7. Directional Microwave for Medium Distances
8. Satellites for Long Distances
COMMUNICATIONS SERVICE PROVIDERS (p. 445)
1. Key Considerations for Communications Media
END OF MODULE (p. 448)
1. Summary: Student Learning Outcomes Revisited
2. Key Terms and Concepts
3. Short-Answer Questions
4. Assignments and Exercises
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EXTENDED LEARNING MODULE D
KEY TERMS AND CONCEPTS
KEY TERMS AND CONCEPTS
Bandwidth
Bluetooth
Broadband
Cable modem
Cat 5 (Category 5)
Client/server network
Coaxial cable (coax)
Communications medium
Communications protocol (protocol)
Communications satellite
Communications service provider
Computer network
Digital Subscriber Line (DSL)
Ethernet card
Firewall
Handspring
Home PNA (Phoneline Networking Alliance)
Infrared
International virtual private network (International VPN)
Local area network (LAN)
Microwave
Municipal area network (MAN)
Network hub
Network interface card (NIC)
Optical fibre
Palm
Palm Operating System (Palm OS)
Peer-to-peer-network
Personal digital assistant (PDA)
PNA adapter Card
Pocket PC
Pocket PC OS (Windows CE)
Private network
Public network
Repeater
Router
Satellite modem
Switch
Telephone modem (modem)
Value-added network (VAN)
Virtual private network (VPN)
Wide area network (WAN)
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EXTENDED LEARNING MODULE D
WiFi (Wireless Fidelity or IEEE 802.11b)
Wired communications medium
Wireless network access point (wireless access point)
Wireless communications media
Wireless Internet service provider (wireless ISP)
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EXTENDED LEARNING MODULE D
SUPPORT
Extended Learning Modules
 XLM/C – this is a good module to cover if your students need an introduction to computer hardware
and software, essential for understanding networks.
 XLM/B – which discusses computer crime and forensics and would be good to cover in conjunction
with this one since it discusses how networks can be abused.
Web Support (www.mcgrawhill.ca/college/haag)
 Wireless technologies
 Web access
 Network technologies
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EXTENDED LEARNING MODULE D
Introduction
INTRODUCTION
This module covers networks, including the basic components common to all networks. It includes
discussions of small home or dorm networks, different types of Internet access, business networks,
classifications of networks, telecommunications media, and communications service providers.
Key Term: Computer network - two or more computers connected so that they can communicate with
each other and share information, software, peripheral devices, and/or processing power.
Basic Principles of Networks (p. 426)
Key Points:
 An important point to stress is that networks come in all sizes from two computers connected to
share a printer, to the Internet, which joins millions of computers.
 Some basic principles apply to all networks no matter what size they are:
 Each computer on the network must have a network card.
 The network usually has a connecting device like a hub or a router that ties the computers
together.
 The network must have some sort of communications channel to allow information to move
between devices.
 Each computer must have network operating system software.
Concept Reinforcement: Adding Value – Class Participation
 Start by asking your students what sort of tasks they use computer networks for.
 For example, if they access journal article databases, they most likely use a network.
 If they enroll in classes online or use a course delivery tool like Blackboard, they use a network.
 And, of course, if they use e-mail or the Web, they’re using a network.
PEER-TO-PEER HOME NETWORK
This section provides an introduction to peer-to-peer networks, the simplest kind of networks that share
information, software, and peripheral devices.
Key Points:
 A peer-to-peer network, at its most basic, would connect two computers or two computers and a
printer so that the two computers could use the same printer.
 You can set up a simple home network in one of two ways: (1) with Ethernet cards, network
cabling, and a hub; or (2) with existing phone wiring.
Key Term: Peer-to-peer network – a network in which a small number of computers share hardware
(such as a printer), software and/or information.
Home Network Components (p. 427)
Key Points:
 For a small number of computers, you can set up a network with four basic components
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Peer-to-Peer Home Network

The components are
 Ethernet cards – one for each computer. Direct your students’ attention of the photo of an
Ethernet expansion card for desktop computers and the PC Card Ethernet adapter for
notebooks.
 a home router – to connect the computers together
 cables – as channels between devices on which information will travel
 operating system software that supports information transfer between computers – any of the
newer versions of Windows
Key Term: Network interface card (NIC) – an expansion card or a PC Card (for a notebook computer)
that connects your computer to a network and provides the doorway for information to flow in and out.
Key Term: Ethernet card – the most common type of network interface card.
Key Points:
 Network connecting devices tie computers together so that information and messages can pass
between them.
 Network connecting devices include network hubs, switches, and routers. See Figure D.1 on page
428 for a graphical representation of the differences between these devices.
 A network hub allows only one connection at a time. It’s similar to a four-way stop in which only
one car can cross the intersection at a time.
 A switch allows multiple communications links simultaneously, like a four-leaf clover that allows
cars to move in several different directions at once.
 A router is a switch with the capability of keeping traffic traveling between computers in a network
from being transmitted outside that network, and checking incoming traffic before letting it through.
 For home networks, routers are probably the best, since a router, because it keeps local network
traffic in and monitors traffic from the outside, also acts as a firewall and will bring a measure of
protection to a home network.
Key Term: Network hub – a device that connects multiple computers into a network.
Key Term: Switch – a device that connects multiple computers into a network in which multiple
communications links can be in operation simultaneously .
Key Term: Router – a device that acts as a smart hub connecting computers into a network, and it also
separates your network from any other network it’s connected to.
Key Term: Firewall – software and/or hardware that protects a computer or network from intruders.
Key Points:
 The most common transmission medium for a home network is Cat 5 cable.
 Cat 5 cable has RJ-45 connectors on each end. One end plugs into a computer and the other end
goes into the home router.
 RF-45 connectors look just like regular phone cable connectors, except that they’re bigger.
 See Figure D.2 on page 429 for a typical home network configuration.
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EXTENDED LEARNING MODULE D
Peer-to-Peer Home Network
Key Term: Cat 5 or Category 5 cable – a better constructed version of the phone twisted-pair cable.
Concept Reinforcement: Extended Learning Module B – Computer Crime and Forensics
 Since a lot of computer crime is perpetrated using networks, this would be a good place to include
material from module B.
 Firewalls and other protective measures are discussed in module B.
 Chapter 8 is also relevant here since, in that chapter, we discuss ethics and the use and value of
information that is usually stored in networks
Wireless Access to Your Home Network (p. 429)
Key Points:
 Many networks now allow wireless access.
 For wireless information transmission to work, you need a wireless access point on the network.
 A wireless access point has a receiver and a transmitter to move information in and out of the
network.
 The notebook computer must have a wireless PC card, which also has a receiver and a
transmitter.
 WiFi and Bluetooth are two types of wireless technology that are popular at the moment.
Key Term: Wireless network access point or wireless access point – a device that allows
computers to access a network using radio waves.
Key Term: WiFi or Wireless Fidelity or IEEE 802.11b – a way of transmitting information in wave form
that is reasonably fast and is often used for notebooks.
Key Term: Bluetooth – technology that provides entirely wireless connections for all kinds of
communications devices.
Key Points:
 Hardware alone is never enough, you always need software for the hardware do its job.
 For peer-to-peer home networks, the Windows operating system is all you need.
Home Network with Existing Phone Wiring (p. 430)
Key Points:
 Another way to get a home network is to use existing phone wiring. See Figure D.3 on page 430
for a graphical representation of how PNA works.
 You won’t need cabling or a router
 All you need are PNA adapter cards for each computer.
Key Term: Home PNA – allows you to network your computers using telephone wiring.
Key Term: PNA adapter card – an expansion card that you put into your computer to act as a doorway
for information flowing in and out.
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EXTENDED LEARNING MODULE D
Peer-to-Peer Home Network
Concept Reinforcement: Adding Value – Class Participation
 You can find out more about creating a small network with existing phone wiring at
www.homepna.org
 The site has lots of information that would be useful if your students want to set up a small
network.
INTERNET ACCESS
This section discusses the five ways you can access the Internet.
Key Points:
 Your choices for Internet connections are
 telephone or dial-up modem
 DSL
 cable modem
 satellite modem
 wireless ISP connection
 DSL, cable, satellite and wireless are all broadband
Key Term: Broadband – a high-capacity telecommunications pipeline capable of providing high-speed
Internet service.
Telephone or Dial-Up Connection (p. 431)
Key Points:
 For a telephone or dial-up modem you need a phone line, a modem, and an ISP.
 A modem converts the digital signal from your computer to the analog signal of the phone line, i.e.
it modulates the signal for outgoing messages. For incoming messages, the modem demodulates
the signal (see Figure D.4 on page 431).
 Telephone modems are often part of more modern motherboards in both desktop and notebook
computers.
 A telephone modem is the slowest type of Internet connection.
Key Term: Telephone modem or modem – a device that connects your computer to your phone line
so that you can access another computer or network.
Concept Reinforcement: Adding Value – Class Participation
 Sometimes people are bothered by the dialing and screeching sounds when using a dial-up
modem
 If your students ask you how to silence this process, tell them the following
 Your modem's speaker is controllable through the Windows Control Panel.
 Select Start, then Settings, and highlight Control Panel.
 Double-click on the Modems icon.
 Highlight the modem you are using, click the Properties button and go to the General tab.
Move the volume slide bar down or off and click OK.
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EXTENDED LEARNING MODULE D
Internet Access
Digital Subscriber Line (DSL) (p. 432)
Key Points:
 A DSL Internet connect uses phone lines as the transmission medium, but it’s much faster than a
dial-up modem, and uses only part of the phone line so that the line is still available for phone calls
(see Figure D.5 on page 432).
 The big disadvantage is that, to get a DSL connection, you have to live within 4.8 km or so of the
phone company building or one of its COs (Central Offices) which are located throughout
metropolitan areas.
 Your speed, which depends on the type of DSL you have and how far from the phone company
your computer is, is guaranteed, i.e. it will not slow down with more users on the system.
Key Term: Digital Subscriber Line (DSL) – a high-speed Internet connection using phone lines, which
allows you to use your phone for voice communications at the same time.
Cable Modem (p. 432)
Key Points:
 A cable modem allows you to get access to the Internet through the same cable that brings you
cable TV.
 A splitter in your home divides the signal between your cable modem and the TV (see D.6 on page
433).
 Your service will slow down as more people in your neighbourhood get onto the Internet with their
cable modems.
Key Term: Cable modem – a device that uses your TV cable to deliver an Internet connection.
Concept Reinforcement: Adding Value – Class Participation
 Students may ask your advice on whether a cable modem is better than DSL or vice versa.
 The answer to this question is a hotly debated issue.
 On major advantage of DSL modems is that their speed is constant because you have your own
“pipeline” to the Internet, and you’re not affected by the number of people concurrently using the
ISP’s service.
 All cable modems from one provider share a single “pipeline” to the Internet. The speed of your
transmission will depend partly on how many other people are using the pipeline. The more
people, the slower the traffic for all users.
Internet over Satellite (p. 433)
Key Points:
 A newer mode of Internet access is Internet over satellite (IoS) which uses a satellite dish similar to
the satellite dish that delivers TV service (see Figure D.7 on page 434).
 Satellite Internet access requires:
 an appropriate satellite dish
 a satellite modem
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EXTENDED LEARNING MODULE D
Internet Access


cable between the satellite modem and the dish
an unobstructed view to the sky in the direction of the equator, above which the satellite floats.
Key Term: Satellite modem – a modem that allows you to get Internet access from a satellite dish.
Internet Access on Multiple Computers (p. 434)
Key Points:
 DSL, cable, or satellite Internet connections will allow you to use a single Internet connection for all
the computers on your home network.
 Simply connect the router to the appropriate modem.
 The router has private IP addresses which it will assign to the computers on the network and route
traffic accordingly.
Concept Reinforcement: Adding Value – Class Participation
 If you have, or can get, an old router, modem card, Ethernet card, or any other network parts, it
will help reinforce your presentation to pass the part around the classroom and let students
examine it for themselves.
 Even if you only have a piece of phone wire, you can bring it in and say that an RJ-45 connector
is just like the phone connector, but bigger.
Wireless Internet Connection (p. 434)
Key Points:
 ISPs are increasingly offering wireless Internet connections.
 Usually you access the wireless ISP with a notebook computer or PDA.
 To get access, you have to be within range of a wireless access point of the ISP.
 Cell phones are now being sold that allow Internet access.
Key Term: Wireless Internet service provider or wireless ISP – does the same job as standard
Internet service providers except that you don’t need a wired connection for access.
Key Term: Personal digital assistant (PDA) – a small hand-held computer that helps you surf the
Web and perform simple tasks such as note taking, calendaring, appointment scheduling, and
maintaining an address book.
Key Term: Palm – a type of PDA that runs on Palm Operating System (Palm OS).
Key Term: Handspring– a type of PDA that runs on Palm Operating System (Palm OS).
Key Term: Pocket PC – a type PDA that runs on Pocket PC OS (Windows CE).
Key Term: Palm Operating System (Palm OS) – the operating system for Palm and Handspring
PDAs.
Key Term: Pocket PC OS – the operating system for Pocket PCs.
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EXTENDED LEARNING MODULE D
Internet Access
BUSINESS NETWORKS
Business networks are usually client/server networks rather than peer-to-peer. The server or servers
are usually high-end PCs or minicomputers.
The advantages of client/server networks include
 decreased cost in software since a network license is often cheaper than separate software
packages for each computer
 easier and faster updates of software packages
 better control and security when shared information is on the server
Client/Server: A Business View (p. 435)
Key points:
 The term “client/server network” can mean either the physical structure of a network or the way in
which tasks are allocated among server and clients.
 There are five basic client/server models and they differ according to three factors (see Figure D.9
on page 438).
1. where presentation of information is formatted
2. where processing of the logic or business rules takes place
3. where the database and database management system are located
 Model 1 – Distributed Presentation: server handles database management, logic, and part of the
presentation function
 Model 2 – Remote Presentation: client handles all presentation functions.
 Model 3 – Distributed Logic: server handles all data management and client handles presentation
function, but logic processing is shared. Figure D.10 on page 440 shows a graphic representation
of Model 3.
 Model 4 – Remote Data Management: server handles data management only and client processes
logic and presentation formatting.
 Model 5 – Distributed Data Management: client handles all presentation formatting and logic
processing but server and client share data management duties. See Figure D.8 on page 436 for a
graphical representation of this implementation.

Note that “distributed” in the model type means “shared” and remote means “all of it on one side or
the other.”
Key Term: Client/server network – a network in which one or more computers are servers and
provide services to the other computers which are called clients.
Concept Reinforcement: Team Work – What Sort of Computer Network Does Your School Have
(p. 436)
 This assignment is intended to get your students to relate the network discussion to the network
they use at school.
 This will only be a helpful exercise if the computer technicians at your school don’t object to
getting lots of questions from students.
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Business Networks

As an alternative, you could ask one of your institution’s technical people to come to the class and
talk about your network.
Client/Server: A Physical View (p. 439-441)
Key Points:
 Physical implementations of networks are many and varied.
 The same basic principles apply to large networks as well as small, but large networks are much
more complicated.
 There are many more hardware and software considerations in a large client/server network than
in a small peer-to-peer.
 In a large network, there are many types of connecting devices, and other devices like
multiplexors, and so on.
 A client/server network requires server operating system software.
 Figure D.11 on page 441 shows a client/server network for a typical network in a medium-sized
business.
Key Term: Communications protocol or protocol – a set of rules that every computer follows to
transfer information
Concept Reinforcement: On Your Own – How Is a Server Different from a Client Computer? (p.
443)
 This assignment will help your students better understand the concept of a server.
 Any of the major computer-sales Web sites have servers.
 Generally, a server has more memory than a regular PC.
 A server usually has large hard disk capacity, and perhaps multiple disks.
 Often servers have RAID systems to mirror everything saved to the hard disk.
LANs, MANs, WANs, AND COMMUNICATIONS MEDIA
Networks can be classified by geographic distance and network computers can be connected by many
types of communications media.
Classification of Networks by Geographic Distance (p. 442)
Key Points:
 There are three basic types of networks that are classified by geographic distance
 Local area network (LAN)
 Municipal area network (MAN)
 Wide area network (WAN)
Key Term: Local area network (LAN) – covers a limited geographic distance, such as an office,
building, or a group of buildings.
Key Term: Municipal area network (MAN) – covers a metropolitan area.
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LANs, MANs, WANs, and Communications Media
Key Term: Wide area network (WAN) – covers large geographic distances, such as a state, a country,
or even the entire world.
Concept Reinforcement: Adding Value – Class Participation
 Be sure to stress to your students that building, maintaining, administering and managing
networks is one of the hottest fields in computing today.
 Ask students to find job descriptions and salary ranges for network administrators.
Telecommunications Media: The Paths That Carry Information (p. 442)
Key Points:
 Networks transmit information from one place to another by means of communications media.
 Communications media can be wired or wireless.
 Wired communications media include
 Twisted-pair cable
 Coaxial cable
 Optical fibre
 Wireless communications media include
 Microwave
 Satellite
 Infrared
Key Term: Communications medium - the path, or physical channel, in a network over which
information travels.
Key Term: Wired communications medium - transmits information over a closed, connected path.
Key Term: Wireless communications medium – transmits information through the air.
Bandwidth
Key Points:
 Communications media capacity is measured in bits per second (bps), thousands of bits per
second (Kbps), and millions of bits per second (Mbps), and gigabits per second (Gbps).
 Band width is comparable to the size of a drinking straw; the wider the straw, the more liquid you
get per unit of time.
Key Term: Bandwidth – capacity of the communications medium, refers to the amount of information
that a communications medium can transfer in a given amount of time.
Wired Communications Media (p. 443)
Key Points:
 Twisted-pair cable comes in several varieties, from Cat 1 to Cat 5 (see photo on page 443).
 Most of the world’s phone system is twisted pair.
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EXTENDED LEARNING MODULE D
LANs, MANs, WANs, and Communications Media
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

Cat 1 twisted pair cable provides a slow but reasonable reliable conduit for phone service, but can
cause errors in data transmission. Cat 5 is much more reliable.
Coax is an alternative to twisted-pair cable (see photo on page 443).
Coax is commonly used for leased-line private networks .
Key Term: Coaxial cable or coax – is one central wire surrounded by insulation, a metallic shield, and
a final case of insulating material.
Key Points:
 Optical fibre cable has many advantages over twisted-pair and coax.
 It has the diameter of a human hair with a capacity of over 1,400 Mbps and much better security.
 Fibre optic cable is expensive and more difficult to install and maintain than twisted-pair and coax.
Key Term: Optical fibre – uses a very thin glass or plastic fibre through which pulses of light travel
(see photo on page 443).
Concept Reinforcement: Adding Value – Class Participation
 Optical fibre cable is very expensive to install, so it’s usually used as the main cable, or backbone,
of a network only.
 If you bring fibre optical fibre to each computer, you’ll spend a lot more in installation and will also
have to buy special network cards that can cost up to 10 times the cost of regular network cards.
Wireless Communications Media (p. 444)
Key Points:
 Wireless communications media are good for rugged terrain, large distances, and situations where
people are in motion.
 Wireless communications media radiate information through the air.
 Data security is one of the problems with wireless communications, and encryption methods are
improving.
Infrared and Omnidirectional Microwave for Short Distances (p. 444)
Key Points:
 Infrared transmission is good for short distances and is used to connect hand-held devices to other
devices like printers.
 Wireless keyboards and mice are usually infrared.
 Apart from infrared, microwave can also be used for short distances.
 WiFi and Bluetooth are two types of microwave transmission for short distances.
Key Term: Infrared – a wireless communications medium that uses light waves to transmit signals or
information.
Key Term: Microwave – a type of radio transmission.
Concept Reinforcement: Adding Value – Class Participation
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LANs, MANs, WANs, and Communications Media


Many wireless products use infrared. To expand this discussion you could mention devices other
than wireless keyboards and mice.
At www.irda.org/products/index.asp you can find a list that includes cell phones, digital cameras,
toys, and wrist watches.
Directional Microwave for Medium Distances (p.444-445)
Key Points:
 Microwave can be used for medium distances.
 Since microwave waves radiate in a straight line and don’t follow the curvature of the earth,
repeaters are used to bring the signal back down and strengthen it before sending it on.
 See Figure D.12 on page 444 for an illustration of medium distance microwave data transmission
Key Term: Repeater – a device that receives a radio signal, strengthens it and sends it on.
Satellites for Long Distances (p. 445)
Key Points:
 For very long distances, like from one continent to another, you can also use microwave data
transmission.
 These microwave transmissions are captured by satellites in space, 22,500 miles up and then
bounced back down to earth.
 Many businesses use satellite data transmission because it’s a cost-effective way of moving a lot
of information.
 See Figure D.13 on page 445 for an illustration of how it works.
Key Term: Communications satellite – microwave repeater in space.
Concept Reinforcement: Adding Value – Class Participation
 Students may ask about putting up satellite dishes in places where they are prohibited by zoning
regulations, condominium rules, or other regulations. Legally speaking, as long as the dish is less
than one metre across (about 39 inches) it’s protected by Congress in Section 207 of the
Telecommunications Act of 1996, in the Federal Communications Commission’s Over-the-Air
Reception Devices Rule.
 This rule “prohibits restrictions that impair a person's ability to install, maintain, or use an antenna
covered by the rule. It applies to state or local laws or regulations, including zoning, land-use or
building regulations, private covenants, homeowners' association rules, condominium or
cooperative association restrictions, lease restrictions, or similar restrictions on property within the
exclusive use or control of the antenna user where the user has an ownership or leasehold
interest in the property.”
 See the details of the rule at the FCC Web site at www.fcc.gov/mb/facts/otard.html#Q
COMMUNICATIONS SERVICE PROVIDERS
There are several different options available for network construction and use.
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Communications Service Providers
Key Points:
 Network ownership determines your rights to the network and the level of cost, availability, services
provided, speed, and security you get.
 Small networks are usually private.
 For wider reach, you can outsource network construction to one of many communications service
providers.
 Your choices are public, private, value-added , and virtual private networks.
 See the table in Figure D14 on page 446 for a comparison of network ownership options.
Key Term: Communications service providers – third parties who furnish the conduit for information.
Key Term: Public network – a network on which your organization competes for time with others.
Key Term: Private network – the communications media that your organization owns or exclusively
leases to connect networks or network components.
Key Term: Value-added network (VAN) – a semipublic network that provides services beyond the
movement of information from one place to another.
Key Term: Virtual private network – uses software to establish a secure channel on the Internet for
transmitting data.
Key Term: International virtual private network (International VPN)– a virtual private network that
depends on services offered by phone companies of various nationalities.
Key Considerations for Communications Media (p. 448)
Key Points:
 To determine the most appropriate communications medium, the following factors need to be
considered
 Capacity or bandwidth
 Reliability
 Cost
 Distance
 Mobility
Concept Reinforcement: Team Work – What’s the Big Deal with Frequencies? (p. 447)
 Students sometimes have a difficult time understanding that wireless devices use a part of the
radio frequency spectrum.
 This assignment helps to clarify this fact.
 The answers are:
 WiFi: 2.4 GHz
 GPS Devices: 1227 to 1575 MHz
 Microwave Ovens: 2.5 GHz
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EXTENDED LEARNING MODULE D
Communications Service Providers
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Police Radar Guns: x-band guns 10.525 GHz and k-band guns 24.15 GHz
TV Channels 2-6: 54-88 MHz
Wildlife tracking Collars: 215-220 MHz
CB Radio: 26.96 – 27.41 MHz
Aviation Navigation: 960 – 1251 MHz
Cordless Phones: 40 -50 MHz or newer models run at 900 MHz
D-18
EXTENDED LEARNING MODULE D
Summary: Student Learning Outcomes Revisited
SUMMARY: STUDENT LEARNING OUTCOMES REVISITED
In each chapter and module, we revisit the student learning outcomes as a mechanism and format for
summarizing the chapter.
You’ll find this content for Extended Learning Module D on pages 448-449.
Following the adage “Tell them what you’re going to tell them, tell them, and then tell them what you
told them,” you should walk through the summary with your students.
You should also inform your students that the summary is great support for studying for exams.
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EXTENDED LEARNING MODULE D
Short-Answer Questions
SHORT-ANSWER QUESTIONS (p. 450)
1.
What is a computer network?
ANSWER: A computer network (or a network) is two or more computers connected so that they
can communicate with each other and share information, software, peripheral devices, and/or
processing power. p. 426
2.
What is a peer-to-peer network?
ANSWER: A peer-to-peer network is a network in which a small number of computers share
hardware (such as a printer), software and/or information. p. 427
3.
How is a peer-to-peer different from a client/server network?
ANSWER: A client/server network is a network in which one or more computers are servers and
provide services to the other computers which are called clients. On the other hand a peer-to-peer
network is a network in which a small number of computers share hardware (such as a printer),
software and/or information, and there is no server. p. 435
4.
What is an Ethernet card?
ANSWER: An Ethernet card is the most common type of network interface card. p. 427
5.
What does a network hub do?
ANSWER: A network hub is a device that connects multiple computers into a network. p. 427
6.
How does an Ethernet network work?
ANSWER: An Ethernet network works by broadcasting every message to all the computers on the
network. All the computers check the recipient address, and the computer that is the recipient accepts
the message. p. 428
7.
What is Cat 5 cable used for?
ANSWER: Cat 5 cable is used to connect computers and other devices into a network hub so that
information can pass between the computers and devices. p. 428
8.
What is Bluetooth?
ANSWER: Bluetooth technology provides entirely wireless connections for all kinds of
communications devices. p. 430
9.
What do you need to have a dial-up connection to the Internet?
ANSWER: You would need a phone line, a telephone or dial-up modem and an ISP. p. 431
10. How is a DSL Internet connection different from a telephone modem connection?
ANSWER: Both use the phone line, but DSL is faster and doesn’t tie up the phone line when you’re
on the Internet. p. 432
11. What is a satellite modem?
ANSWER: A satellite modem is a modem that allows you to get Internet access from a satellite
dish. p. 433
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EXTENDED LEARNING MODULE D
Short-Answer Questions
12. How is client/server model 1 different from client/server model 2?
ANSWER: In client/server model 1 the presentation function is shared between the server and client,
whereas in client/server model 2, the presentation is all on the client side. p. 437
13. What does WiFi do?
ANSWER: A WiFi or Wireless Fidelity or IEEE 802.11b is a way of transmitting information in wave
form that is reasonably fast and is often used for notebooks. p. 429
14. What are communications service providers?
ANSWER: A communications service provider is a third party who furnishes the conduit for
information. p. 445
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EXTENDED LEARNING MODULE D
Short-Question Answers
SHORT-QUESTION ANSWERS
1.
A network card in each computer, a connecting device, a communications medium, and a network
operating system.
QUESTION: What are the basic components of a computer network? p. 426
2.
A network in which one or more computers are servers and provide service to the other computers
which are called clients.
QUESTION: What is a client/server network? p. 435
3.
A wireless communications medium that uses a red light that’s below what your eye can see.
QUESTION: What is infrared? p. 444
4.
The amount of information that communications medium can transfer in a given amount of time.
QUESTION: What is bandwidth? p. 442
5.
A semipublic network that provides services beyond the movement of information from one place to
another.
QUESTION: What is a value-added network (VAN)? p. 446
6.
It is a better-constructed version of ordinary phone cable.
QUESTION: What is Cat 5 cable? p. 428
7.
It’s used as a communications medium for phone networks.
QUESTION: What is twisted-pair cable? p. 443
8.
It covers large geographic distances, such as a state, a country, or even the entire world
QUESTION: What is a WAN? p. 442
9.
A device that acts as a smart hub connection into a network and separates your network from any
other network it’s connect to.
QUESTION: What is a router? p. 428
10. A standard for wirelessly accessing a local area network.
QUESTION: What is WiFi? p. 429
11. A device that uses your TV cable to deliver an Internet connection.
QUESTION: What is a cable modem? p. 433
12. It uses a very thin glass or plastic tube through which pulses of light travel.
QUESTION: What is optical fibre? p. 443
13. A network on which your organization competes for time with others.
QUESTION: What is a public network? p. 445
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EXTENDED LEARNING MODULE D
Short-Question Answers
14. It takes a message, strengthens it, and passes it along.
QUESTION: What is a repeater? p. 444
15. The paths, or physical channels, in a network over which information travels from one place to
another.
QUESTION: What are communications media? p. 444
D-23
EXTENDED LEARNING MODULE D
Assignments and Exercises
ASSIGNMENTS AND EXERCISES (p. 450-451)
1.
Investigate Cell Phone Technology. A wireless device that you may have used, or perhaps use all
the time, is a cell phone. A cell phone is actually a radio (with a transmitter and a receiver) and uses
radio waves of certain frequencies. There are different systems (called cellular access technologies)
for cell phones: TDMA, GSM, CDMA. Go to the Web and find the answers to the following questions
(hint: a good place to look is www.howstuffworks.com )
A. What do the letters stand for?
B. What’s the difference between them?
C. Why are they called “cell” phones?
D. Why was this “cellular” method used in the first place?
DISCUSSION:
A. The letters stand for the following
 CDMA: Code Division Multiple Access
 GSM: Global System for Mobile Communications
 TDMA: Time Division Multiple Access
B. Following is a summary of the difference between them.
 TDMA fits three digital conversations into a FDMA channel, enabling compatibility with
FDMA while enabling digital services and boosting capacity by a factor of three. This
technology has no flexibility for varying digital data rates and has no accommodation for
silence in a conversation.
 CDMA systems have no channels, but instead encode each call as a coded sequence
across the entire frequency spectrum. Each conversion is modulated with a unique code
that makes it distinguishable from other calls in the frequency spectrum. CDMA offers far
greater capacity and variable data rates depending on the audio activity, many more users
can be fit into a given frequency spectrum and higher audio quality can be provided.
 GSM uses a modified and far more efficient version of TDMA. GSM keeps the idea of
timeslots and frequency channels, but the timeslots are smaller. However, when a call is
inactive fewer timeslots are used. To facilitate filling in gaps left by unused timeslots, calls
do “frequency hopping” in GSM. This means that calls will jump between channels and
timeslots to maximize the system’s usage. A control channel is used to communicate the
frequency hopping and other information between the cell tower ad the phone.
C. The system is called “cellular” because it uses many base stations to divide a service area into
multiple ‘cells’ or areas of service. Cellular calls are transferred from base station to base station
as a user travels from cell to cell.
D. The cellular method was used in the first place because researchers looked at early versions of
mobile phones and realized that by using small cells with frequency reuse they could increase
traffic capacity. However, at the time the technology to do this was not yet available. Later, the
FCC later granted AT&T a number of radio-spectrum frequencies so that they could research the
new technology.
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EXTENDED LEARNING MODULE D
Assignments and Exercises
2.
Find out about Personal Digital Assistants. Many people have personal digital assistants (PDAs)
which are handheld computers that allow you to perform many computer tasks wirelessly. Some of
the features of PDAs are calendar management, appointment management, mini spreadsheets and
word processing capabilities, Web access, and sometimes even double as a cell phone.
Do some research on PDAs and answer the following questions:
A. What are three other features common in PDAs that were not listed above?
B. What does the term “synching” mean?
C. What are the two types of handwriting recognition systems used on PDAs.
DISCUSSION:
A. Your students could come up with a variety of features. A few examples would be e-mail, voice
recorders, MP3 players, and digital cameras.
B. “Synching” means passing information between PDA’s and desktop or notebook computers. It
allows you to add or update programs as well as have a backup of all your PDA information. This
term is also called synch or synchronizing.
C. The two types of handwriting recognition systems used on PDA’s today are Graffiti and JOT.
Calligrapher is also another very notable handwriting recognition system.
3.
What Are the Internet Access Options in Your Area? Write a report on what sort of Internet
connections are available close to you. How many ISPs offer telephone modem access? Is DSL
available to you? Is it available to anyone in your area? Does your cable company offer a cable
modem? Can you get wireless Internet access in your area? Compare each available service on
price and extras like a help line, or people who will come out to your home and help you if you’re
having difficulties. What type of Internet connection do you currently use? Do you plan to upgrade in
the future? If so, to what type of connection? If not, why not?
DISCUSSION:
 Answers from your students will depend, of course, on where you’re located.
 The point of this exercise it to make sure your students are aware of the options available to
them
 As an added feature to this assignment, ask students to compare what’s available in their home
town compared to their college town.
D-25
EXTENDED LEARNING MODULE D
Assignments and Exercises
4.
Investigate Building Your Own Home Network. Build your own home network on paper. Assume
you have the computers already and just need to link them together. Find prices for hubs and routers
on the Web. Also research Ethernet cards and cables. If you were to get a high-speed Internet
connection, like a cable modem or DSL modem, how much would they cost? Can you buy your own
or would you have to rent the modems from the phone or cable company?
DISCUSSION:
 Your students answers could vary based on the hardware specifics that they chose, but below is
a range of prices for all hardware components mentioned.
 At the time of writing you can buy a range of hubs that vary in size and performance. 4-5 port
hubs usually range in price from about US $30 to $50.
 At the moment you can buy a range of routers that vary in size and performance based on your
needs. Four-port routers usually range in price from US $20 (after rebates) to $150
 There are various makes of Ethernet cards on the market, but they generally cost somewhere in
the region of US $40 or $50.
 Cables of various lengths are available at prices in the neighbourhood from US $3 for 3ft. cables
to $5 for 7 ft cables.
 The cost of a high-speed Internet connection will vary depending on where you’re located. At the
time of writing, cable modems range in price from about US $80 to $130. DSL modems range in
price from US $200 to $700.
5.
Investigate Satellite Radio. At the time of writing there are two satellite radio stations: Sirius and
XM. Do a little surfing on the Web and find out if there are any others now. Also find out what you
have to buy to install each type, how much the antenna costs, how the system would work in your
car, and how much the monthly subscription is.
DISCUSSION:
 At the time of writing, there are currently only two satellite radio systems, Sirius and XM. But, that
situation could have changed by the time you assign this project.
 The cost of the satellite radio system right now typically includes a monthly charge of US $9.99
for XM and US $12.95 for Sirius.
 There are two options for what you need to receive satellite radio and the options are as follows:
you can get a portable unit that sends a signal through your radio player or you could get a
satellite ready receiver and a satellite ready radio.
 Typical cost for antennas range from US $50 to $80.
6.
Find out about Firewalls. Go to the Web and find out about software and hardware that protects
your computer and home network, respectively.
A. If you only have one computer connected to the Internet, then a software firewall like Zone Alarm
will most likely be enough protection from intruders. Find three different firewall software
packages on the Web. A good place to start looking would be the sites that sell anti-virus
software. Compare the firewall software on price and features.
Some sites to try are as follows:
 Symantec at www.symantec.com
D-26
EXTENDED LEARNING MODULE D
Assignments and Exercises
 TREND Micro at www.trendmicro.com
 Virus List (a virus encyclopedia) at www.viruslist.com
 McAffee at www.mcaffee.com
B. If you have a home network, then you’d be well advised to check into a hardware firewall. One
place to look is at the LinkSys site (www.linksys.com) or any site that sells computer hardware.
DISCUSSION:
 Some possible examples are as follows:
 McAffee: Personal Fire Wall
Price US $49.95 (2 year subscription)
Features include the following:
 Protection of personal Information
 Monitors Outbound Application Traffic
 Immediate Alerts
 Detailed Event Information
 Blocks or Allows Specified Internet Systems
 Hackerwatch.org Integration
 Automatic, 24x7 Online Updates
 Multi-Layered Security

Symantec: Norton Personal Firewall
Features include the following:
 Intrusion Detection
 Privacy Control
 Security Monitor
 Ad Blocking
 Inbound and Outbound Monitoring
 Network Notification
Price US $49.95

Smith Micro: CheckIt Firewall
Features include the following
 User friendly
 Identify Intruders
 Protect your data
 Always on Safety
Price US $29.99
D-27