Transcript PPT U3Ch01 Lessons 1 thru 3

Computer Literacy for
3
IC
Unit 3: Living Online
Chapter 1:
Understanding the Internet
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Learning Targets
96. I can describe how to create faster, more
reliable communications
97. I can describe networks of computers
98. I can describe the birth of the World Wide
Web
99. I can describe how to connect to the Internet
100. I can discuss financing and controlling the
Internet
101. I can describe security, privacy and ethics in
regard to the Internet
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Traditional Phone Systems
• Circuit Switching
• wires leading back to a
central office
• Star Configuration
• Switchboard Operator
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System to Survive Major Losses
• Advanced Research Projects Agency (ARPA)
• Created by J.C.R. Licklider in 1962
• Concept of a “Galactic Network”
• Advanced Research Projects Agency Network
(ARPANET)
• Network of Networks
• Keep one path alive
• Computer provided millions of instructions per second
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TCP/IP – Transmission Control
Protocol/Internet Protocol
• Data divided into small packets
• Consisting of bits (b) and bytes (B)
• Checksum – sum of numbers in packet
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Data Travels – Increased Survival
© 2010 Pearson Education, Inc. | Publishing as Prentice Hall.
TCP/IP
• Protocol
• Groups of rules used to manage data exchange
• File Transfer Protocol (FTP)
• Enables users to transfer files between computers
• Telnet
• Enables users to logon to remote computer
• E-mail (1972)
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Networks of Computers
• Local Area Network (LAN)
• Small geographical connection of PCs to share files
and resources (printers, scanners, etc).
• Each element is a node
• Connected to a network server
• Peer-to-Peer network
• Computers are connected directly to each other
without a server
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Servers on a Network
• File server – storing and retrieving files
• Print server – coordinating use of a shared
printer
• Web server – storing and providing Web pages
• Database server – interpreting requests and
retrieving data from a database
• Mail server – managing electronic mail
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Client – Server Relationship
• Client
• A computer connected
to a server in a
client/server network
• Server
• A computer that
manages a network and
all its devices
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Methods of Connections
•
•
•
•
•
Infrared (IR)
Twisted pair
Coaxial cable
Wireless
Fiber optic cable
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Type
Cost
Distance
Security Speed
Twisted
Pair
Lowest
<100
meters
Good
Good
Coax
Medium
100-500
meters
Good
Good
Radio
(wireless)
Low
Up to
miles
Poor
Fair
Infrared
Low
Short and
line of
sight
Excellent
Excellent
Fiber
optic
High
Many
miles
Excellent
Excellent
© 2010 Pearson Education, Inc. | Publishing as Prentice Hall.
Network Wire Codes
• 10BASE-T
• 10 – indicates speed = 10
MBPS
• T – indicates twisted pair
• 10BASE-T4
• 4 – indicates 4 twisted
pairs
• 1000BASE-T
• 1000 MBPS
• 10Base-2
• (Thin Coax)
• 10Base-5
• (Thickwire Coax)
• 10Base-F
• (Fiber)
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Wide Area Networks (WAN)
• Further apart than a hundred meters
• Connections
• Twisted pair for short distances (inside buildings or
small offices)
• Broadband coax, fiber optic, or radio for intermediate
distances
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Connections Between Networks
• Bridge
• Used to send and receive data when networks are
connected and use the same protocols
• Gateway
• Used to send and receive data when networks are
connected and use different protocols
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Addresses on the Internet
World Wide Web
• http://www.australia.gov.au
http
Protocol
australia
Domain name
gov
g (TLD)
Generic Top Level
Domain
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au
cc (TLD)
Country
Code Top
Level
Domain
Role of Domain Name System
• Host
• Internet Protocol (IP) address
• Domain Name System (DNS)
• Domain Name Server
• Internet Corporation for Assigned Names
and Numbers (ICANN)
• Registry
• Internet Service Provider (ISP)
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Internet Backbone
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Birth of World Wide Web
• Browser
•
•
•
•
•
Mosaic
Netscape
Microsoft Internet Explorer
Mozilla Firefox
Apple’s Safari
• Hypertext Markup Language (HTML)
• <b>hello</b> - the word hello bolded
• Hyperlinks – www.weather.com
© 2010 Pearson Education, Inc. | Publishing as Prentice Hall.