Network and Internet Fundamentals
Senior 1 · ICT
Network and Internet Fundamentals
Lesson 1 of 5
22 min
When you send a WhatsApp message from Musanze to a cousin in Rusizi, it arrives in about a second. When a teacher in the staffroom prints the class list on the printer in the office next door, nobody carries a flash disk between the rooms. Both happen because devices are joined together in networks.
In this lesson you will learn what a computer network is, what networks are used for, and how networks are named by the area they cover: PAN, LAN, MAN and WAN.
Mutesi's family has a smartphone, a laptop and a smart TV. All three connect by Wi-Fi to one small box, a router, and the router is connected to the internet. Now the laptop can send a film to the TV, and all three devices use the same internet connection. Without planning it, the family has built a small network.
A computer network is two or more computers and other devices that are linked together so that they can exchange data and share resources.
Four words describe every network:
| Advantages | Disadvantages |
|---|---|
| Sharing printers and one internet line saves money | Cables, routers and installation cost money |
| Messages and files move quickly | A virus can spread from one computer to the others |
| Files can be stored and backed up in one place | If a central device fails, many users lose access at once |
| Users can work together on the same files | Hackers may try to steal shared data, so it must be protected |
| Type | Full name | Area covered | Example |
|---|---|---|---|
| PAN | Personal area network | Around one person, a few metres (about 10 m) | A phone linked by Bluetooth to wireless earphones and a smartwatch |
| LAN | Local area network | One room, one building or one site | A school computer lab; Mutesi's home Wi-Fi |
| MAN | Metropolitan area network | A town or a city | A university linking its campuses in different parts of Kigali |
| WAN | Wide area network | A country, a continent or the whole world | A bank linking its branches in all 30 districts of Rwanda |
The internet is the largest WAN of all. It is a network of networks that joins millions of LANs around the world.
Notice that the type depends on the area the network covers, not on how many devices it has. A LAN in a big office can have more devices than a small WAN.
Drawing a network helps you understand it. This is a simple map of one school's network, starting from the internet:
Reading the map: the 30 lab computers, the printer and the projector computer plug into a switch, a box that joins devices inside the building. The router links the school network to the internet service provider (ISP) and also sends out Wi-Fi. Everything inside the school is one LAN; the internet beyond the ISP is a WAN. The shared resources are the printer and the internet connection.
Tip
Memory hook: the letters grow with the area. PAN = Person, LAN = Local building, MAN = Metropolitan (city), WAN = Wide world. In exams, classify a network by the area it covers, never by the number of devices.
Name the type of network: (a) a laptop and a wireless mouse joined by Bluetooth; (b) the computers in one office block; (c) the network that lets you visit a website in the USA from Kigali.
Solution: (a) PAN, because it covers one person's desk; (b) LAN, because it covers one building; (c) WAN (the internet), because it crosses continents.
Explain the difference between a node and a resource.
Solution: A node is any device connected to the network. A resource is something the nodes share. A shared printer is both: it is connected (a node) and it is shared (a resource).
Give two advantages and two disadvantages of joining the computers of a school into a network.
Solution: Advantages (any two): one printer and one internet line are shared, which saves money; files can be shared and backed up centrally; students and teachers communicate quickly. Disadvantages (any two): equipment and installation cost money; a virus can spread to every computer; if the switch or router fails, everyone loses access; shared data must be protected from hackers.
Project: my school's network. With your teacher's permission, walk through your computer lab. Count the computers and printers, find the switch and the router, and ask how the school gets its internet connection. Then draw a map like the one above and answer: What type of network is it? Which resources are shared?
Solution guide: Your map should show every device joined to a switch or to Wi-Fi, the switch joined to the router, and the router joined to the ISP. The network inside the school is a LAN. Shared resources usually include the printer, the internet connection and any shared folders. Compare your map with a classmate's and correct any missing links.
Summary
Sources and credits
The worked examples, the school network map and the practice items, including the project, were written by Ganzaa.
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
Internet
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ISP (fibre line)
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[ Router ] ))) Wi-Fi for teachers' laptops
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[ Switch ]
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30 PCs Printer Projector PC