Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.

McGraw-Hill Technology Education

IntroductionBasic

Concept of Computer Network

Basic Concept of Computer NetworkPrepared by: EngAbdirahman Hassan NourPrepared by: EngAbdirahman Hassan Nour Golis University Berbera Golis University Berbera

Prepared by: EngAbdirahman Hassan Nour Prepared by: EngAbdirahman Hassan Nour

9A-2

Definition of Computer network

• A Computer network is a collection of computers and devices Connected together via communication devices and transmission media. For example it my connect computers, printers and scanners.

9A-3

Definition of Network Communication

• Communication describes a process in which two or more computer, devices transfer data, instructions and information.

9A-4

Advantage of Computer networks • Sharing of Devices such as printer and

scanner• Sharing program / software • Sharing files • Sharing data • Sharing information• Sharing of single high-speed internet

connection• Better communication using internet

services such as email, mailing list and internet Relate chat (IRC)

9A-5

Disadvantage of Computer Network

• The larger network becomes, the more difficult it is to manage.

• If the network stops operating system, then it may not be possible to access various resources

• Computer Viruses: If any computer system in a network gets affected by computer virus, there is a possible threat of other systems getting affected too.

9A-6

Sharing Data

File server contains documents File server contains documents used by other computers.used by other computers.

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Types of Network

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Local Area Network (LAN)

• A local area network is a network that connects computers and devices in a limited geographically area such as a home, school computer laboratory, office building.

9A-9

Metropolitan Area Network (MAN)

• Metropolitan Area Network (MAN) is high speed network that connect local area network in Metropolitan Area such as city or town and handles bulk of communication activity across the region.

• A MAN typically includes one or more LAN but covers a smaller geographically area than a WAN.

9A-10

Wide Area Network (WAN)• Wide Area Network is a network that covers a large

geographically area such country or the world

• WAN combines many types of media such as telephone lines, cables

and radio wave. A WAN

can be one large network

or can consist of two or

more LANs connected

together.

9A-11

Difference Between the types of Computer network

9A-12

Network Architecture

• Network Architecture is the over all design of a computer network that describes how a computer network is configured and what strategies are being used.

• It also know as network model or network design.

• Two main network architecture:

9A-13

Server and Clients

• A network server is a computer designed to process requests and deliver data to other (client) computers over a local network or the Internet.

• A Client is a computer that

retrieves information

from or uses resources

provided by a server

or main computer.

9A-14

Difference Between Server, Client and Peer to Peer

9A-15

Network Communication Technology

• State the types of network communication technology:

i) Intranetii) Extranetiii) Internet

• Define the types of network communication technology:

i) Intranetii) Extranetiii) Internet

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Types of Network Communication

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Intranet• An intranet is a private network within an organization that

resembles the internet.• organizations use intranets to provide information to their

employees.• typical applications include electronic telephone directories, email

addresses, employee information, internal job openings and much more.

9A-18

Extranet

• Is a private network that connects more than one organizations

• many organizations use the internet technologies to allow suppliers, customers and business partner limited access to their network

• the purpose is to increase efficiency and reduce costs

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Internet• is a public network• it is worldwide collection of networks that links million of

business, government agencies, educational institution and individuals.

• internet users can access service like web browsing, email, file transfer, mailing list, chat rooms, instant messaging and newsgroups.

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Difference Between Internet, Intranet and Extranet

DifferencesDifferences IntranetIntranet ExtranetExtranet InternetInternet

Used for Private Private Public

Types of users Provide information for

organization employees

Provide information to

suppliers, customers and

business partner

Provide information for

public

Usages Telephone directories, internal job

opening, employee

information

Access data, check status, place

orders, send email

Access all kinds of information

Security High Use virtual private network (VPN) technology to

communication over the internet

more secure

Loose

Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.

McGraw-Hill Technology Education

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Prepared by: EngAbdirahman Hassan NourPrepared by: EngAbdirahman Hassan Nour Golis University Berbera Golis University Berbera