the nuts and bolts of networks how can you use networks to your advantage? chapter 7
TRANSCRIPT
The Nuts and Bolts of Networks
How Can You Use Networks to Your
Advantage?
Chapter 7
©2003 The McGraw-Hill Companies
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
Network operating system software
Communications media
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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 files to avoid keeping multiple
copies on different computers
Share hardware among several
computers
Share broadband Internet
connections
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 CardNetwork Interface Card
Connecting DeviceConnecting Device
Network Operating SystemNetwork Operating System
Pathways for InformationPathways for Information
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Ethernet Cards
Ethernet card is the most common type of NIC. Three forms of Ethernet cards are:
Integrated card
(on Motherboard)
Expansion Card PC Card
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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, and the other into the Ethernet Card
RJ-45 Connectors
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Popular Network Operating System Software
Windows
(Windows 95 and newer)
Netware
Linux
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Wireless Network Access
IrDAIrDAUses red light
(infrared) below what your eye can
see
Bluetooth Uses radio waves up to
30 feet
WiFiUses radio waves
Up to about 300 feet
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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 bi-directional 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
DSL ModemDSL ModemCable ModemCable Modem Satellite ModemSatellite Modem
Share broadband Internet
connections
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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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MinicomputersMinicomputers MainframesMainframesHigh-End PCsHigh-End PCs
Client/Server Computers
Client/Servers can be
Client/Servers can be
SimNet 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 generallymake computer information accessible toemployees and facilitate working in groups
Intranet is an internal network that uses Internet technologies. Intranets generallymake computer information accessible toemployees 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
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
CellularTelephone Global
PositioningSystem
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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
p.7.207 Fig. 7.11
• 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
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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
Ground control - Five ground stations, located in different parts of the world, that monitor the system
Receivers - Devices used to find out where we are
Satellites - 24 satellites, each completing its own orbit every 12 hours at about 12,000 miles above the earth
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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
Optical fiber
InfraredBluetooth
WiFi
Satellite
Twisted PairMicrowave
Cat 5
Cable TV
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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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DSL ModemDSL Modem
144 Kpbs = 144,000 bits per144 Kpbs = 144,000 bits per
Second to 1.54 MbpsSecond to 1.54 Mbps
= 1,540,000 bits per second= 1,540,000 bits per second
Telephone ModemTelephone Modem
56 Kpbs 56 Kpbs
= 56,000 bits per second= 56,000 bits per second
Examples of Bandwidth Speed
SimNet 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 ProjectsE-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 ProjectsEthics, 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 Projectson 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 Firewalls4. Find Out what Network Terms Mean
What’s a ping?
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Hands On ProjectsGroup 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