Computer Networks and Internet Use

1. Introduction to Computer Networks

A computer network is a group of computers and devices connected together to share resources, data, and communication services.

Main Purposes of Networks

  • files and information
  • Sharing Sharing hardware (printers, scanners)
  • Communication (email, messaging, video calls)
  • Accessing the internet
  • Centralized storage and security

2. Types of Computer Networks

a) LAN (Local Area Network)

A network covering a small area such as:

  • Home
  • School
  • Office

Characteristics:

  • Fast speed
  • Privately owned
  • Low cost

Example:
Computers connected in a school lab.


b) WAN (Wide Area Network)

A network covering large geographical areas.

Characteristics:

  • Connects cities or countries
  • Uses public communication systems
  • More expensive

Example:
The Internet.


c) MAN (Metropolitan Area Network)

Covers a city or large campus.

Example:
A university network across several buildings.


d) PAN (Personal Area Network)

Small network around one person.

Example:
Bluetooth connection between phone and earbuds.


3. Network Devices

Router

Connects networks and directs internet traffic.

Switch

Connects devices within the same network.

Modem

Connects a network to the internet service provider (ISP).

Access Point

Provides wireless internet connection.

Network Interface Card (NIC)

Allows a computer to connect to a network.


4. Transmission Media

Wired Media

  • Ethernet cables
  • Fiber optic cables

Advantages:

  • Faster
  • More secure

Disadvantages:

  • Limited mobility


Wireless Media

  • Wi-Fi
  • Bluetooth
  • Satellite

Advantages:

  • Mobility
  • Easy installation

Disadvantages:

  • Can be slower
  • More security risks


5. Network Topologies

A topology is the arrangement of devices in a network.

Star Topology

All devices connect to a central device.

Advantages:

  • Easy to manage
  • Failure of one device does not affect others

Disadvantages:

  • Central device failure affects entire network


Bus Topology

All devices share one communication line.

Advantages:

  • Cheap

Disadvantages:

  • Difficult troubleshooting


Ring Topology

Devices connect in a circular pattern.

Advantages:

  • Organized data flow

Disadvantages:

  • Failure of one device can disrupt network


6. The Internet

The Internet is a worldwide network of interconnected computers.

Services Provided by the Internet

  • Email
  • Web browsing
  • Video conferencing
  • Cloud storage
  • Online gaming
  • Social networking


7. Internet Terminology

Website

A collection of web pages.

Web Browser

Software used to access websites.

Examples:

  • Google Chrome
  • Mozilla Firefox
  • Microsoft Edge

URL (Uniform Resource Locator)

The address of a webpage.

Example:
https://www.example.com

ISP (Internet Service Provider)

A company that provides internet access.



8. Uses of the Internet

Education

  • Online classes
  • Research
  • E-books

Communication

  • Email
  • Messaging apps
  • Video calls

Examples:

  • WhatsApp
  • Zoom

Business

  • Online shopping
  • Banking
  • Advertising

Entertainment

  • Streaming music and movies
  • Online games

Examples:

  • YouTube
  • Netflix


9. Advantages of the Internet

  • Fast communication
  • Easy access to information
  • Online learning opportunities
  • Remote work capability
  • Global connectivity


10. Disadvantages of the Internet

  • Cybercrime
  • Privacy issues
  • Addiction and distraction
  • Spread of false information
  • Viruses and malware


11. Internet Safety and Security

Strong Passwords

Use:

  • Uppercase and lowercase letters
  • Numbers
  • Symbols

Antivirus Software

Protects computers from malware.

Examples:

  • Norton Antivirus
  • Avast Antivirus

Safe Browsing Tips

  • Avoid suspicious links
  • Do not share personal information
  • Use secure websites (https)
  • Keep software updated


12. Cybersecurity Threats

Virus

A harmful program that damages files.

Phishing

Fake messages designed to steal information.

Hacking

Unauthorized access to systems.

Malware

Software intended to harm computers.


13. Cloud Computing

Cloud computing allows users to store and access data online instead of on a local computer.

Examples:

  • Google Drive
  • Dropbox
  • Microsoft OneDrive

Advantages:

  • Access files anywhere
  • Backup storage
  • Easy sharing


Summary

Computer networks allow devices to communicate and share resources efficiently. The internet is the largest network and is widely used for education, communication, business, and entertainment. Safe and responsible internet use is important to protect information and maintain security online.