4.1a Network devices
Cambridge IGCSE ICT 0417 · Topic 4: Networks and the effects of using them · Paper 1
4.1b Types of network and cloud computing
Cambridge IGCSE ICT 0417 · Topic 4: Networks and the effects of using them · Paper 1
Say each word, then read what it means. Every one is in the glossary too.
Read it here, or open the study page below to go one step at a time with things to try.
A network is two or more devices connected so they can communicate.
Advantages: users can share files, printers and one internet connection, and log on from any computer. Software can be updated and backed up centrally.
Disadvantages: set-up costs, a technician is needed, viruses can spread quickly between computers, and a server failure can stop everyone working.
A NIC is the hardware inside a device that lets it connect to a network, by cable or wirelessly.
Each NIC has a unique MAC address (media access control address), set by the manufacturer. It identifies that device on the network.
A hub connects devices on a LAN. When data arrives, it sends a copy to every device. Each device checks if the data is for it.
A switch also connects devices on a LAN, but it learns the MAC address of each device. It sends data only to the device it is meant for.
A bridge connects two LANs that use the same protocol, so they work as one bigger network.
| Hub | Switch | |
|---|---|---|
| Sends data to | All devices | Only the intended device |
| Uses MAC addresses? | No | Yes, keeps a table of them |
| Network traffic | More, slows the network | Less, so faster |
| Security | Lower: every device receives every packet | Higher: data goes only where it should |
| Cost | Cheaper | More expensive |
Write "a switch is more efficient than a hub because it sends data only to the device with the matching MAC address, so there is less traffic."
A router connects a LAN to another network, usually the internet. It sends data between networks.
It reads the IP address (internet protocol address) in each data packet and works out the best route for it.
A home router often also acts as a switch and a wireless access point, and gives each device a private IP address.
MAC addresses find a device inside one network. IP addresses find a network and a device across the internet. Routers use IP; switches use MAC.
Both send data by radio waves, so no cables are needed.
Wi-Fi connects devices to a network and the internet over a range of about 30 to 100 metres.
Bluetooth connects two devices close together, usually under 10 metres, such as a phone and wireless earphones.
| Wi-Fi | Bluetooth | |
|---|---|---|
| Range | Longer (about 30–100 m) | Short (usually under 10 m) |
| Data transfer rate | Faster | Slower |
| Number of devices | Many on one network | Few, usually pairs |
| Security | Better, with strong encryption (WPA2/WPA3) | Weaker; can be intercepted if left discoverable |
| Power use | Higher | Lower |
| Typical use | Laptops in a school, internet at home | Earphones, smartwatch, wireless keyboard, car hands-free |
Cloud computing means storing files and running software on remote servers, reached over the internet, instead of on your own computer.
Examples: online file storage and online office apps. A school might keep all student work in cloud storage.
The servers are owned by a cloud provider and kept in large data centres.
| Advantages | Disadvantages |
|---|---|
| Files can be reached from any device, anywhere with internet | Needs a reliable internet connection; no internet means no files |
| Provider makes backups, so data is safe if your laptop breaks | Security and privacy depend on the provider; data could be hacked |
| Easy to share and work on the same file together | Ongoing subscription costs |
| Storage can be increased easily without buying hardware | Data may be stored in another country with different laws |
The internet is a worldwide network of networks. It is public: anyone can connect.
An intranet is a private network inside one organisation. It uses the same technology as the internet, but only members (staff, students) can use it. Example: a school intranet with timetables and homework.
An extranet is part of an intranet that selected outsiders can reach with a password. Example: a supermarket lets its suppliers check stock levels.
| Internet | Intranet | Extranet | |
|---|---|---|---|
| Who can use it | Anyone | Members of one organisation | The organisation plus authorised outsiders |
| Content | Public, not checked | Private, controlled by the organisation | Selected private content |
| Size | Worldwide | Usually one organisation | One organisation and its partners |
| Reliability of information | Varies a lot | More reliable, because it is managed | More reliable |
The internet is not the same as the World Wide Web. The internet is the network. The web is the pages you reach over it.
A LAN (local area network) covers one building or site, such as a school. Devices are connected by cables.
A WLAN (wireless LAN) is a LAN where devices connect by Wi-Fi through wireless access points (WAPs).
A WAN (wide area network) covers a large area, such as a country or the world. It joins many LANs. The internet is the biggest WAN. A bank with branches across Spain uses a WAN.
| LAN (cabled) | WLAN | WAN | |
|---|---|---|---|
| Area | One building or site | One building or site | Cities, countries, worldwide |
| Connection | Cables | Radio waves (Wi-Fi) | Telephone lines, fibre, satellite, leased lines |
| Speed | Fast | Usually slower than cable; drops with distance and walls | Slower than a LAN |
| Security | More secure: need physical access to a cable | Less secure: signals can be picked up outside | Needs strong security |
| Advantage | Fast and reliable | Users can move around; no cables to trip over | Links offices far apart |
| Disadvantage | Cables are costly to install; users cannot move | Interference from walls and other devices | Expensive to set up and run |
Open the study page and go one step at a time.
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ICT topic 13Step by step, with exam questions and a quiz.
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ICT topic 11Step by step, with exam questions and a quiz.
Topic 15 · Year 7A network is computers connected to share data. The internet is a network of networks. Data travels in small packets, following rules called protocols.
One question at a time. The reason shows after each answer.