Computer Networks - SSS 1 Note
COMPUTER NETWORKS
Class: SSS 1
Term: Second Term
Week: 1
Duration: 80 Minutes (Double Period)
Topic: Computer Networks
1. Learning Objectives
By the end of the lesson, students should be able to:
- Define a computer network.
- Explain why computers and other digital devices are connected in networks.
- Distinguish between Personal Area Network (PAN), Local Area Network (LAN), Metropolitan Area Network (MAN) and Wide Area Network (WAN).
- Identify common components of a computer network.
- State some uses and benefits of computer networks.
2. Meaning of Computer Network
A computer network allows connected devices to exchange data and make use of shared resources. The devices may be connected using physical cables or wireless communication technologies.
For example, computers in a school computer laboratory can be connected so that they can communicate with one another and share resources such as files, printers and an Internet connection.
Examples of Devices That Can Be Connected in a Network
- Desktop computers
- Laptops
- Smartphones
- Tablets
- Printers
- Servers
- Network storage devices
3. Uses and Benefits of Computer Networks
Computer networks are useful in schools, homes, offices, businesses, banks, hospitals and other organisations.
- Resource sharing: Devices such as printers and storage systems can be shared by several users.
- File sharing: Users can send and access files through a network.
- Communication: Connected devices can exchange messages and other information.
- Internet sharing: Several devices can access an Internet connection through a network.
- Centralised management: Network administrators can manage connected computers and resources.
- Collaboration: Users can work together on shared information and digital resources.
4. Types of Computer Networks
Computer networks can be classified according to the geographical area or distance they cover. Four important types are PAN, LAN, MAN and WAN.
A. Personal Area Network (PAN)
A PAN allows devices belonging to one person to communicate or share data. It commonly uses short-range wireless technologies such as Bluetooth, although wired connections may also be used.
Examples of PAN include:
- A smartphone connected to wireless earbuds through Bluetooth.
- A mobile phone connected to a smartwatch.
- A laptop connected to a phone's Bluetooth or a personal peripheral device.
Characteristics of PAN:
- Covers a very small area, usually around an individual.
- Connects personal devices such as phones, watches, earbuds and laptops.
- Often uses Bluetooth or other short-range connection technologies.
- Is generally smaller in coverage than a LAN.
B. Local Area Network (LAN)
A LAN is commonly used where computers and other devices are located relatively close to one another.
Examples of LAN include:
- A network connecting computers in a school laboratory.
- A network connecting computers and printers in an office.
- A home network connecting laptops, smartphones and other devices.
Characteristics of LAN:
- Covers a relatively small geographical area.
- Usually provides high-speed communication between connected devices.
- Can be connected using cables or wireless technologies.
- Is commonly used in homes, schools and offices.
C. Metropolitan Area Network (MAN)
A MAN can connect several LANs located in different buildings or parts of a city. It is useful for organisations that need to connect facilities that are spread across a metropolitan area.
Examples of MAN include:
- A network linking branches of an organisation within the same city.
- A network connecting several educational institutions within a metropolitan area.
- A city-wide network used to connect different offices or facilities.
Characteristics of MAN:
- Covers a city or metropolitan area.
- Covers a larger area than a LAN.
- Can connect several LANs.
- Is suitable for organisations with facilities in different parts of a city.
D. Wide Area Network (WAN)
A WAN connects networks that are far apart. It can use communication systems such as leased communication links, fibre-optic connections, satellite links and other long-distance communication technologies.
The Internet is the best-known example of a global system of interconnected networks operating across very large geographical areas.
Characteristics of WAN:
- Covers a very large geographical area.
- Can connect networks in different cities, countries or continents.
- Usually involves communication links provided by telecommunications or network service providers.
- Can connect many smaller networks together.
5. Comparison of PAN, LAN, MAN and WAN
| Feature | PAN | LAN | MAN | WAN |
|---|---|---|---|---|
| Meaning | Personal Area Network | Local Area Network | Metropolitan Area Network | Wide Area Network |
| Coverage | Very short distance around a person | Small area | City or metropolitan area | Very large geographical area |
| Example | Phone connected to Bluetooth earbuds | School computer laboratory | Network linking offices across a city | Network connecting offices in different countries |
| Common connection | Bluetooth or short-range connection | Ethernet or Wi-Fi | Links connecting several LANs | Long-distance communication links |
6. Components of Computer Networks
A computer network requires different hardware and communication components to connect devices and allow them to communicate.
A. Computers and Other End Devices
These are the devices used by people or applications to send, receive or process information on the network.
Examples include:
- Desktop computers
- Laptops
- Smartphones
- Tablets
- Network printers
- Servers
B. Network Interface Card (NIC)
A Network Interface Card (NIC) is a hardware component that enables a computer or other device to connect to a network. A NIC may provide a wired Ethernet connection or wireless network connection.
C. Switch
A switch is a networking device used to connect multiple devices within a network. It receives data and forwards it to the appropriate connected device.
D. Router
A router is a networking device that connects different networks and directs data between them. A router can, for example, connect a local network to the Internet.
E. Transmission Media
Transmission media are the paths through which data travels from one network device to another.
Examples include:
- Ethernet cables
- Fibre-optic cables
- Wireless radio signals
F. Server
A server is a computer or system that provides services or resources to other computers on a network, known as clients.
For example, a file server can store files that authorised users on a network can access.
G. Network Software and Protocols
Network software and communication protocols help devices communicate and exchange information correctly.
A network protocol is a set of rules that determines how devices communicate and exchange data over a network.
7. Wired and Wireless Networks
Computer networks can use either physical cables or wireless communication methods.
| Wired Network | Wireless Network |
|---|---|
| Uses physical cables to connect devices. | Uses wireless signals to connect devices. |
| Commonly uses Ethernet cables or fibre-optic cables. | Commonly uses Wi-Fi or other wireless technologies. |
| Can provide a stable connection where properly installed. | Allows devices to connect without a physical network cable. |
8. Simple Example of a School Network
Consider a school computer laboratory containing ten computers, a network printer, a switch, a router and an Internet connection.
The computers can be connected to the switch. The switch allows the computers to communicate within the local network. The router can connect the local network to other networks, including the Internet. The printer can also be connected to the network so that authorised users can print documents.
Computers → Switch → Router → Internet
A network printer can also be connected to the switch for shared printing.
9. Classroom Activity
Activity: Identify a Network
- Look around your school and identify places where computers or digital devices are connected.
- Identify whether the network is likely to be a PAN, LAN, MAN or WAN.
- List at least four components that may be found in the network.
- Explain one resource that users could share through the network.
10. Summary
- A computer network connects two or more digital devices so that they can communicate and share resources.
- PAN connects personal devices over a very short distance, usually around one person.
- LAN covers a small geographical area such as a home, school or office.
- MAN covers a city or metropolitan area and can connect several LANs.
- WAN covers a very large geographical area such as different cities, countries or continents.
- Common network components include computers, NICs, switches, routers, transmission media and servers.
- Networks may use wired or wireless communication.
- Computer networks support communication, resource sharing, file sharing, collaboration and Internet access.
11. Evaluation Questions
- What is a computer network?
- State four uses or benefits of computer networks.
- What is a Personal Area Network (PAN), and give one example?
- What is a Local Area Network (LAN)?
- What is a Metropolitan Area Network (MAN)?
- What is a Wide Area Network (WAN)?
- State two differences between LAN and WAN.
- List five components of a computer network.
- What is the function of a network switch?
- What is the function of a router?
- Differentiate between wired and wireless networks.
12. Assignment
- Explain the differences between PAN, LAN, MAN and WAN in a table.
- List six components of a computer network and state the function of each.
- Draw a simple diagram showing how computers in a school laboratory could be connected to a switch, router and Internet connection.
13. Interactive Revision Quiz
Choose the best answer for each question, then click Submit Quiz to see your score.
CMPNOTE: Free Digital Technologies learning resources for Nigerian secondary school students and teachers.
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