The Nuts and
Bolts of Networks
How Can You Use
Networks to Your
Advantage?
Chapter 7
Student Learning Outcomes
1. Identify and describe the four basic
components of networks
2. Describe what you need to set up a small
peer-to-peer network at home
3. Identify how you would wirelessly access
a wired network
4. Define client/server networks and what
differentiates them from peer-to-peer
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Student Learning Outcomes
5. Describe the three segments of a cellular
phone system
6. Explain the function of each of the three
segments of a global positioning system
7. Define the five types of communications
media used in business networks
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Introduction
Networks play a prominent role in our lives,
and enable us to communicating effectively.
Computer network – a collection of
computers that support the sharing of
information, software, and hardware devices.
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7.1 Networks: The Big
Picture
• The term “network” can mean a few
computers that are connected, or it can
mean literally thousands of computers tied
together
• The largest network on the planet is the
Internet with millions and millions of
computers
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Common Characteristics of
all Networks
Network cards
Connecting
devices
Communications
media
Network operating
system software
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Network Principles
• Network card in each computer to act as a
doorway for information to move in and out
• One or more connecting devices to connect the
computers together and to pass messages
between them i.e., Hub
• Cable to provide a pathway for information to
move around on or wireless devices that propel
information through the air
• A network operating system to move information
in and out of the computer
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Network Hardware &
Software
NIC
Cable and
connector
Hub
Network
Operating
System
SimNet
Concepts Support CD: “Connectivity
Concepts” and “What Is a Network”
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Advantages: Home Network
Share hardware
among several
computers
Share broadband
Internet
connections
Share files to avoid
keeping multiple
copies on different
computers
Transfer
information
between computer
devices
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Network Definitions
• Local area network (LAN) is a network in
the same building, complex, or small
geographic area
• Peer-to-peer network simplest kind of
network in which all computers are equal,
and each can have access to devices and
files on the others
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Network Definitions
• Client/server network a network in which
one or more computers are servers and
provide services to the other computers
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Wired Home Networks
• Peer-to-peer network
– Network where a few computers share
hardware and information
– All computers are equal, and each can have
access to devices and files on the others
– Each computer independently stores its own
software and information, but can access the
information on the other computers
– All computers can access devices connected
to any of the other computers
SimNet
Concepts Support CD: “Peer-to-Peer Systems”
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Peer-to-Peer Network
Components
Network Interface Card
Connecting Device
Pathways for Information
Network Operating System
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Ethernet Cards
Ethernet card is the most common type of NIC.
Three forms of Ethernet cards are:
Integrated card
Expansion Card
PC Card
(on Motherboard)
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Network Hubs
• Network hub is a device that connects
computers into a network, broadcasting
all messages it gets to every computer
on the network, although only the
intended recipient computer takes the
message
• Computers that are not the recipients of
the message simply ignore it
• Hubs can only handle one-way
information traffic at a time
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Network Switches
• Switch is a device that connects
computers into a network and, unlike a
hub, sends messages only to the
computer that is the intended recipient
• Switches can handle multiple
communications channels at the same
time
• Switch can temporarily segment parts of
the network with high traffic from the rest
of the network
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Network Home Routers
• Home router is a device that connects
computers into a network, and also
connects dissimilar networks together,
separating the network traffic and keeping
local traffic inside its own network
• Home router can handle multiple
communications channels
• Home router keeps local traffic inside your
home network
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Wired Communications
Media
• Cat 5 cable with RJ-45
connectors on each end
is the most common
type of cable used in
home networks
• Similar to ordinary
phone cable, but more
robust
• One RJ-45 connector
plugs into the router,
RJ-45
and the other into the
Connectors
Ethernet Card
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Popular Network Operating
System Software
Windows
(Windows 95 and
newer)
Linux
Netware
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Wireless Network Access
Bluetooth
Uses radio waves up to
30 feet
WiFi
Uses radio waves
Up to about 300 feet
IrDA
Uses red light
(infrared) below
what your eye can
see
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Wireless Network Access
Point
• A WAP is a device that allows computers to
access a network using radio waves
• A WAP has a transmitter and a receiver for bidirectional flow of information
• It has an antenna that radiates radio waves
through the air and captures incoming waves
p.7.201 Fig. 7.7
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Completely Wireless
Network
• To set up a home wireless network all you
actually need is to:
– Install a wireless network card into each
desktop computer
– Ensure that all wireless devices are within, at
most, 300 feet of each other
SimNet
Concepts Support CD: “Wireless Communications”
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Sharing an Internet
Connection
Share broadband
Internet
connections
DSL Modem
Cable Modem
Satellite Modem
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7.3 Large Networks
• 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
• Servers have hardware, software, and/or
information that the client computers can
access
• Servers are usually powerful computers
with large storage systems
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Client/Server Computers
Client/Servers
can be
High-End PCs
SimNet
Minicomputers
Mainframes
Concepts Support CD: “The Client/Server Relationship”
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Setting up a Client/Server
Network
• Large networks require:
– Network cards
– Communications media
– Network operating
systems on all
computers in the network
– At least one connecting
device – a hub or switch
– to tie the computers
together
p.7.203 Fig. 7.8
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Large Organizational Network
p.7.204 Fig. 7.9
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Organizational Uses of
Networks
Intranet is an internal network that uses
Internet technologies. Intranets generally
make computer information accessible to
employees and facilitate working in groups
Extranet is the portion of a company’s
network that allows customers or suppliers
of a company to access parts of an enterprise’s
intranet
SimNet
Concepts Support CD:
“Intranets and Extranets” and “Network Software and Network
Administration”
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Collaboration Systems
• Collaboration system is software that allows
people to work together
• Any system that incorporates e-mail, chat
rooms, instant messaging, e-mail and/or any
other form of communications and exchange is a
collaboration system
• Web-based collaboration tools use the power of
the Internet to enable people to work together
effectively and efficiently
• P2P collaboration system is software that
enables people to communicate and share
documents between peers without going through
a central server
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Collaboration Systems
p.7.206 Fig. 7.10
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Two Widely Used Wireless
Networks
Cellular
Telephone
Global
Positioning
System
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Cellular Telephone – A Form
of Wireless Network
• Cell phones send
and receive
information in the
form of radio
waves, using a
range of
frequencies
• System
identification
code (SID) is a
unique number
that the FCC
assigns a carrier
• Mobile telephone
switching office
(MTSO) stores a cell’s
identification number in
its database so that it
can find you when calls
come in for you
p.7.207 Fig. 7.11
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Global Positioning System (GPS) –
Another Form of Wireless Network
• GPS is a navigational
system that uses
satellites to tell you
where you are, how
fast you’re going, and
what direction you’re
headed in
p.7.209 Fig. 7.12
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Three Major Parts of a GPS
Satellites - 24 satellites,
each completing its own
orbit every 12 hours at
about 12,000 miles
above the earth
Receivers - Devices
used to find out where
we are
Ground control - Five
ground stations, located
in different parts of the
world, that monitor the
system
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7.4 Communications Media
• All communications between computers
are either wired or wireless
• Wired communications media transmit
information over a closed, connected path
• Wireless communications media
transmit information through the air
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Examples of
Communications Media
• Communications media paths, or
physical channels, in a network over which
information travels
Cat 5
WiFi
Optical fiber
Cable TV
Microwave
Twisted Pair
Satellite
Bluetooth
Infrared
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Bandwidth
• Bandwidth the amount of information that
a communications medium can transfer in
a given amount of time
• Capacity of communications medium is
measured in bits per second (bps),
thousands of bits per second (Kbps), or
millions of bits per second (Mbps)
SimNet
Concepts Support CD: “Bandwidth and Data Transmission”
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Examples of Bandwidth
Speed
DSL Modem
Telephone Modem
56 Kpbs
= 56,000 bits per second
SimNet
144 Kpbs = 144,000 bits per
Second to 1.54 Mbps
= 1,540,000 bits per second
Concepts Support CD: “The Client/Server Relationship”
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Twisted-Pair
• Advantages:
• Varieties include Cat
5, Cat 3, and Cat 1
• Relatively
inexpensive and
fairly easy to install
and maintain. Costs
of cabling is low at
up to 64 kilobits per
second
• Disadvantages:
• Easy to tap into
and so is not very
secure
• Possibility of
distortion in
information being
transferred
p. 7.211 Fig. 7.15
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Optical Fiber
• Advantages:
• Fastest and most
efficient medium for
wired communication
• Cabling is very small,
capacity is large, and
offers greater security
than with twisted-pair
• Attempts at tapping
are easy to detect
• Disadvantages:
• Very expensive and
difficult to install and
maintain
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Wireless Communications Media:
Medium Distances
• Microwave communications media are
line-of-sight information transmission
• Microwave signal cannot follow the curved
surface of the earth
• Distances greater than 20 miles require a
repeater to receive the radio signal,
strengthen it, and send it on
• Microwave signals require a clear path
from the sender to the receiver
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Microwave Transmission
p. 7.213 Fig. 7.16
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Wireless Communications Media:
Long Distances
• Communications satellites are actually
microwave repeaters in space
• Solve the problem of line-of-sight as the
transmission shoots up into the sky in a straight
line and then shoots back down to earth again
• Stationed approximately 22,500 miles above the
earth
• Satellite links are very expensive, and generally
used by large organizations only
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Communications Satellites
p. 7.213 Fig. 7.17
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7.5 Consumer Q & A
1. Does it Matter What Type of Cable
Modem I Get if I Want to Share a
Broadband Internet Connection?
2. How Do I Turn On File and Device
Sharing?
3. Which Cell Carries Use Which Type of
Cell Networks?
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7.6 Key Terms
•
•
•
•
•
•
•
•
•
•
Cat 5 cable
Client/server network
Collaboration system
Communications media
Communications
satellite
Computer network
Ethernet card
Extranet
Global positioning
system
Home router
• Intranet
• Microwave communications
media
• Network Interface card
• Network operating system
• Optical fiber cable
• Peer-to-peeer network
• WiFi
• Wired communications
media
• Wireless communications
media
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Review of Concepts
1. The Eurostar Train System and
Computer Networks
2. Moving Information From Here to There
 If you were a song, how would you move
from one computer to another?
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Hands On Projects
E-Commerce
1. Finding the Right Cell Phone
 Wrong question: Are the local carriers as
good as the national ones?
2. Buying Groceries Online
 Need some potato chips for watching TV?
3. Buying and Renting Videos
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Hands On Projects
Ethics, Security & Privacy
1. Should Big Brother Be Allowed to Watch
Us?
 The British don’t mind being observed while
walking around
 Do you feel the same way?
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Hands On Projects
on the Web
1. Find Out What It Would Cost to Build
Your Own Home Network
2. Investigate Satellite Radio
 Listen to the same radio station while
traveling from New York to L.A.
3. Find Out about Firewalls
4. Find Out what Network Terms Mean
 What’s a ping?
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Hands On Projects
Group Activities
1. Find Out What Makes Servers Special
2. Research Your Institution’s Network
3. Investigate Which GPS Would Suit Your
Needs
 Garmin, Magellan, and Trimble are big
4. Try Using a Collaboration System
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