Revision Notes for Class 8 Computer Science: Computer Network
Access comprehensive revision notes for Computer Network using the CBSE Class 8 Computer Science Network Notes Set 01. Designed to align with the 2026-27 academic syllabus for Class 8 Computer Science, these concept summaries help students streamline their exam preparation and review complex topics efficiently.
Review Computer Network for Class 8 Computer Science
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What Is a Network?
Communication means setting up a link between people or places to share information and resources. It always has a sender (the source), a receiver (the destination) and a communication channel (air, wires, waves or satellite) that carries the data. A computer network is a link of two or more computers connected together to share information and resources.
Advantages of Networking
- Sharing of files: many users can open the same file, for example a school result file used by the exam department and class teachers.
- Sharing of resources: one printer can serve many computers.
- Fast delivery of information: a soft copy reaches the other end instantly, while a letter takes days.
- Low cost of data transfer.
Network Terms
Server: a central computer with large storage and high processing speed that supplies data and resources to the connected computers. Workstation (node): any computer connected to a network. Network Interface Unit (NIU) or Network Interface Card (NIC): a device fitted in each node to connect it to the network. Every card has a unique physical address given by its maker, called the MAC (Media Access Control) address.
Media of Communication
Guided media use a physical path: Ethernet cable, co-axial cable and optical fibre. Unguided media are wireless: radio waves (Bluetooth, Wi-Fi), microwaves (mobile networks, satellite) and infrared (TV remote).
| Medium | Key facts |
|---|---|
| Ethernet cable | Used in LANs; invented by Robert Metcalfe; CAT5 and CAT6 types; speed 100-1000 Mbps. A straight-through cable joins a computer to a hub, switch or router; a crossover cable joins two computers directly. RJ45 connectors are used. |
| Co-axial cable | A single conductor with an insulation layer and a conductive shield; 100 Mbps; used by cable TV operators. |
| Optical fibre | Carries data as light/electromagnetic waves; very high speed (up to 10 Gbps) and capacity, over 3000 telephone lines in one cable; costly and fragile. |
| Bluetooth | Radio waves; short range (up to about 100 m); low power; used for headsets, printers and phones; IEEE 802.15.1. |
| Wi-Fi (Wireless Fidelity) | Radio frequency like Bluetooth but stronger; range about 150 m; needs a Wi-Fi adaptor and access points; no cables needed. |
| WiMAX | Wireless broadband over up to 50 km from the base station; IEEE 802.16. |
| Infrared | Works only over a few feet and in a direct line of sight; it cannot pass through obstructions. |
Types of Network
| Type | Area covered | Features |
|---|---|---|
| PAN (Personal Area Network) | Around one person, up to about 10 m | Laptop, phone and printer linked by Bluetooth or infrared; Bluetooth PANs are called piconets. |
| LAN (Local Area Network) | Office, school or building | Speed 100-1000 Mbps; owned by one person or organisation; shares printers and servers; no tariff for use. |
| MAN (Metropolitan Area Network) | A whole city | Covers more than a LAN but less than a WAN; may join several LANs, for example government departments. |
| WAN (Wide Area Network) | Cities, countries or the world | Speed up to 150 Mbps; connected through a gateway; the Internet is the best example. |
| CAN (Controller Area Network) | Inside a vehicle | Links electronic devices such as airbags, lights, air conditioning and central locking. |
Network Topology
Topology is the physical layout, or shape, of the connections between the nodes of a network.
| Topology | How it works |
|---|---|
| Linear | Nodes are joined one after another; if one node fails, the whole network fails. |
| Bus | All nodes are connected to one common line called the bus; the simplest way to connect many clients. |
| Star | Each node connects to a central hub; if one node fails, the rest keep working. |
| Ring | Nodes form a closed circle; each has two neighbours and data moves in one direction around the ring. |
| Tree | Combines linear, bus and star topologies; easy to expand. |
| Mesh | Every node has a direct link to every other node; data can take many paths, so it is fast. |
Uses of Networks: the "e" Services
- e-Mail: sending and receiving messages worldwide; each user has a unique address.
- e-Commerce: buying and selling goods and services over the web.
- e-Governance: government departments work and exchange information through the internet.
- e-Banking: banking without visiting the bank, using a PIN.
- e-Reservation: booking air, rail and other tickets online.
- e-Learning: lessons, presentations, doubt solving and online exams.
- e-Wallet: mobile payments using an app, such as Paytm, Mobikwik or Freecharge.
Internet and Intranet
The Internet is a Wide Area Network of millions of computers linked all over the world that share data, graphics, sound, software and text. It is called a "network of networks". An Intranet is a private network (LAN, MAN or WAN) of an organisation. Its nodes can be used only by authorised users, and each node has a unique IP address.
Exercise with Answers
1. Fill in the blanks: (a) ______ is a mode of communication established using radio frequency technology. (b) A ______ contains one or more web pages linked with each other. (c) Bluetooth's PAN are also known as ______.
Show answer
Answer: (a) Wi-Fi; (b) website; (c) piconets.
Teacher's Note: A website is a collection of linked web pages.
2. Select the most suitable alternative: (a) Data moves at 100-1000 Mbps in which network? (b) Which cable sends data as electromagnetic waves? (c) Which connects locations within about 100 m? (d) In which network is there no specific tariff? (e) The central computer with large storage and high speed is called? (f) Documents on websites that display information are called?
Show answer
Answer: (a) LAN; (b) fibre optic; (c) Bluetooth; (d) LAN; (e) server; (f) web page.
Teacher's Note: LAN is the answer for both (a) and (d).
3. Differentiate between: (a) LAN and WAN (b) Ethernet and co-axial cable (c) Bluetooth and Wi-Fi.
Show answer
Answer:
| Pair | Difference |
|---|---|
| LAN and WAN | LAN covers a small area such as an office, runs at 100-1000 Mbps and is owned by one organisation. WAN covers cities, countries or the world, and the Internet is an example. |
| Ethernet and co-axial | Ethernet cable has several thin wires in a cover and is used in LANs. Co-axial cable has one central conductor with a shield and is used for cable TV. |
| Bluetooth and Wi-Fi | Both use radio waves. Bluetooth has a short range (about 100 m) and uses little power; Wi-Fi is stronger and has a longer range (about 150 m). |
Teacher's Note: Write one point for each side.
4. Expand these abbreviations: (a) Wi-Fi (b) ISP (c) NIU (d) CAN.
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Answer: (a) Wireless Fidelity; (b) Internet Service Provider; (c) Network Interface Unit; (d) Controller Area Network.
Teacher's Note: Learn all abbreviations by heart.
5. Suggest the answer in one word: (a) Rajat wants employees of his office to share files and resources. Which network? (b) A company opens a branch in a metropolitan city. Which cable can be used? (c) Lakshya wants to move music from his mobile to a new laptop wirelessly. Is it possible, and with which facility?
Show answer
Answer: (a) LAN; (b) optical fibre (or co-axial) cable, as the network covers a city (MAN); (c) Yes, through Bluetooth, if both devices have Bluetooth.
Teacher's Note: The answer depends on the area covered and the distance.
6. (a) What does networking mean in context to computers? Explain its advantages.
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Answer: Networking means linking two or more computers so that they can share information and resources. Its advantages are sharing of files, sharing of resources such as printers, fast delivery of information and low cost of data transfer.
Teacher's Note: See the section on advantages above.
6. (b) What are the different types of network? Explain their characteristics.
Show answer
Answer: The types are PAN, LAN, MAN, WAN and CAN. They differ by the area they cover, from about 10 m for a PAN to the whole world for a WAN. See the table above for the features of each.
Teacher's Note: Remember the order: PAN, LAN, MAN, WAN.
6. (c) What are the common types of media used in guided networking? Explain briefly.
Show answer
Answer: Ethernet cable, co-axial cable and optical fibre. Ethernet is used in LANs, co-axial in cable TV and broadband, and optical fibre carries the highest speed and amount of data but is costly and fragile.
Teacher's Note: Guided means a physical cable is used.
6. (d) Name the wireless network technologies used these days. Explain how they work.
Show answer
Answer: Bluetooth, Wi-Fi, WiMAX, infrared and microwave links. Bluetooth and Wi-Fi use radio waves to send data through the air over short and medium range; WiMAX covers up to 50 km; infrared needs a clear line of sight.
Teacher's Note: Unguided means no cable is used.
Revision Notes and Key Concepts for Class 8 Computer Science Computer Network
Key Concepts and Summary for Class 8 Computer Science Computer Network
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FAQs
You can download the teacher prepared revision notes for CBSE Class 8 Computer Science Network Notes Set 01 from StudiesToday.com. These notes are designed as per 2026-27 academic session to help Class 8 students get the best study material for Computer Science.
Yes, our CBSE Class 8 Computer Science Network Notes Set 01 include 50% competency-based questions with focus on core logic, keyword definitions, and the practical application of Computer Science principles which is important for getting more marks in 2026 CBSE exams.
Yes, our CBSE Class 8 Computer Science Network Notes Set 01 provide a detailed, topic wise breakdown of the chapter. Fundamental definitions, complex numerical formulas and all topics of CBSE syllabus in Class 8 is covered.
These notes for Computer Science are organized into bullet points and easy-to-read charts. By using CBSE Class 8 Computer Science Network Notes Set 01, Class 8 students fast revise formulas, key definitions before the exams.
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