Introduction to Computer Networks - JSS 1 Digital Technologies note

INTRODUCTION TO COMPUTER NETWORKS

Subject: Digital Technologies
Class: JSS 1 (Basic 7)
Term: Second Term
Week: 6
Duration: 80 Minutes (Double Period)
Topic: Introduction to Computer Networks

Learning Objectives

By the end of this lesson, students should be able to:

1. Explain the meaning of a computer network.
2. State reasons for connecting computers in a network.
3. Identify the major types of computer networks.
4. Identify common network devices and explain their functions.
5. State the advantages and disadvantages of computer networks.
6. Differentiate between a computer network and the Internet.

1. Meaning of a Computer Network

Definition: A computer network is a group of two or more computers and other digital devices connected together to communicate and share information or resources.

Computers can be connected using cables or wireless technologies. A network allows connected devices to exchange files, communicate, share printers and, where configured, access the Internet through a common connection.

For example, in a school computer laboratory, several computers may be connected so that students can share files and use the same printer.

2. Reasons for Connecting Computers in a Network

Computers are connected in networks for the following reasons:

1. Sharing files: Users can send and receive documents, pictures and other files.
2. Sharing hardware: Several computers can use shared devices, such as network printers.
3. Communication: Users can exchange messages and communicate through network services.
4. Sharing an Internet connection: Multiple devices can access the Internet through a shared connection.
5. Collaboration: People can work together on documents and projects.
6. Centralised management: An organisation can manage certain files, accounts and resources from central systems.

3. Types of Computer Networks

Computer networks can be classified according to the geographical area they cover. Three common types are LAN, MAN and WAN.

A. Local Area Network (LAN)

A Local Area Network connects computers and other devices within a small geographical area, such as a home, office, school or computer laboratory.

Example: Computers connected within a school's computer laboratory.

B. Metropolitan Area Network (MAN)

A Metropolitan Area Network connects networks across a town or city. It covers a larger area than a typical LAN.

Example: A network connecting offices or facilities in different parts of a city.

C. Wide Area Network (WAN)

A Wide Area Network connects computers or smaller networks over a large geographical area, such as different states, countries or continents.

Example: A company network connecting its offices in Nigeria and other countries.

Network Type	Coverage Area	Example
LAN	Small area	School computer laboratory
MAN	Town or city	Network linking offices across a city
WAN	Large geographical area	Network connecting offices in different countries

Remember: LAN covers a smaller area, MAN generally covers a town or city, while WAN covers a much larger geographical area.

4. Common Computer Network Devices

Network devices help computers connect and communicate. Common examples include the following:

Device	Function
Router	Forwards data between different networks and commonly connects a local network to the Internet.
Switch	Connects devices within a local network and forwards data to the appropriate connected device.
Modem	Provides a communication link over an Internet service provider's access technology.
Network Interface Card (NIC)	Provides a computer or other device with a network connection, either wired or wireless.
Network Cable	Carries data between connected devices in a wired network.
Wireless Access Point	Allows wireless devices to connect to a network through Wi-Fi.

5. Advantages of Computer Networks

The major advantages of computer networks include:

1. Easy sharing of information: Users can exchange files quickly.
2. Resource sharing: Devices such as printers can be shared.
3. Improved communication: Network services help people communicate.
4. Reduced costs: Sharing resources may reduce the need to buy separate equipment for every computer.
5. Better collaboration: Users can work together on projects.
6. Centralised management: Some resources and user accounts can be managed centrally.

6. Disadvantages of Computer Networks

Despite their benefits, computer networks also have some disadvantages:

1. Security risks: Unauthorised users may access information if proper protection is not used.
2. Spread of malware: Malicious software may spread between connected devices.
3. Installation costs: Network equipment and setup may be expensive.
4. Maintenance: Networks require monitoring, repairs and updates.
5. Service interruptions: Equipment failure or connection problems can disrupt access to shared resources.
6. Privacy concerns: Poorly managed networks may expose users' information.

Safety Tip: Use strong passwords, keep devices updated, avoid suspicious downloads and allow only authorised users to access a network.

7. Difference Between a Computer Network and the Internet

A computer network is a connection of computers and other devices that communicate and share resources. The Internet is a worldwide system of interconnected networks that allows devices and services to communicate globally.

Computer Network	Internet
May cover a small or large area.	Connects networks worldwide.
Can operate without being connected to the Internet.	Provides global connectivity through interconnected networks.
May be privately owned and managed.	Consists of many interconnected networks operated by different organisations.
Example: A school's local computer network.	Example: Accessing websites across the world.

8. Class Activity

Activity: Identifying a Computer Network

Imagine that a school has ten computers connected to a switch. The computers share files and use a common network printer. A router connects the school's network to the Internet.

1. What is the connection between the computers called?
2. Which type of network is most suitable for the computer laboratory?
3. What is the function of the switch?
4. What is the function of the router?
5. Can the computers communicate over their local network if the Internet connection fails?

Expected responses: A computer network; LAN; connecting devices within the local network; forwarding data between networks; yes, if the local network remains operational and the required local services are available.

9. Summary

A computer network is a group of connected computers and devices that communicate and share resources. Computers can be networked to exchange files, share hardware, communicate and collaborate. The three common network types studied are LAN, MAN and WAN. Routers, switches, modems, network interface cards, cables and wireless access points support network communication. Networks offer many benefits but require proper security and maintenance. The Internet is a worldwide system of interconnected networks.

10. Evaluation

1. Define a computer network.
2. State four reasons computers are connected in networks.
3. Explain LAN, MAN and WAN.
4. State the functions of a router and a switch.
5. Mention three advantages and three disadvantages of computer networks.
6. Differentiate between a computer network and the Internet.

11. Assignment

1. Define a computer network and list five reasons for networking.
2. Explain LAN, MAN and WAN, giving one example of each.
3. State the functions of a router, switch, modem and network interface card.
4. Write four advantages and three disadvantages of computer networks.
5. Draw a simple diagram showing four computers connected to a switch and a router.

12. Online Quiz

Choose the correct answer to each question and click Submit Quiz to see your score.

1. What is a computer network?

A single computer without connections Two or more connected devices that communicate or share resources A type of computer keyboard A computer game

2. Which network type is commonly used within a school computer laboratory?

WAN MAN LAN GPS

3. Which device forwards data between different networks?

Monitor Keyboard Speaker Router

4. Which of the following is an advantage of computer networks?

Sharing files and printers Increased security risks in every situation Guaranteed elimination of all computer problems Prevention of all communication

5. Which statement about the Internet is correct?

It is another name for a printer. It is a worldwide system of interconnected networks. It works only inside one classroom. It is a type of network cable.

CMPNOTE | Digital Technologies Lesson Notes