Transcript Introduction-to

Introduction to Computer Networks
Chapter 2
INTRODUCTION TO COMPUTER
NETWORKS
Learning outcomes
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The difference between networks and internets
The difference between logical and physical
addresses
What is a protocol in the context of computer
networking
How protocols are used on remote computers to
communicate easily
Explain the concept of layering
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OSI ,
TCP/IP and
hybrid models
Reading
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Joe Casad, Teach Yourself TCP/IP, Chs 1-2
William Buchana, Mastering the Internet, Ch. 3
Neil Briscoe, Understanding the 7-layer OSI model, July 2000.
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http://pcnetworkadvisor.com
Julian Moss, Understanding TCP/IP (first part September 1997)
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http://pcnetworkadvisor.com
What is a network?
A network consists of two or more computers
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connected by network media
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.i.e cables, telephone lines, radio waves
share the same resources such as database, printer
Exchange files
Exchange electronic message between each others
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Email
Example of a simple network
How are they linked?
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Computers on a
network may be linked
through:
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cables,
telephone lines,
radio waves, satellites or
wireless technologies
An example of a network
Router
Hub
Bridge
Hub
Internet
Segment
Node
Introduction to Computer Networks
Applications of Networks
Resource Sharing
Hardware (computing resources, disks, printers)
Software (application software)
Information Sharing
Easy accessibility from anywhere (files, databases)
Search Capability (WWW)
Communication
Email
Message broadcast
Remote computing
Distributed processing (GRID Computing)
Categories of networks
Local Area Network
• A LAN is a network that is used for communicating among
computer devices, usually within an office building or
home
• LAN’s enable the sharing of resources such as files or
hardware devices that may be needed by multiple users
• Is limited in size, typically spanning a few hundred
meters, and no more than a mile
• Is very fast, with speeds from 10 Mbps to 10 Gbps
• Requires very little wiring, typically a single cable
connecting to each device
• Has lower cost compared to MAN’s or WAN’s
LAN
LAN (Continued)
Metropolitan-Area Networks (MAN)
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MAN is designed extended over an entire city.
• May be wholly owned and operated by a private company, or it
may be a service provided by a public company, such as a local
telephone company.
Wide-Area Networks (WAN)
•Provides long-distance transmission of data, voice, image, and video
information over large geographic areas
WAN (Continued)
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WANs connect larger
areas, such as whole
states, or even the world.
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Transoceanic cables and
satellites are used to
connect WANs