Networks: Routers, Wi-Fi and Bluetooth, Cloud Computing and Network Types

This guide covers 4.1, Networks, the first half of Topic 4 in Cambridge IGCSE Information and Communication Technology 0417. It follows Topic 3, Storage devices and media and covers the hardware, connection methods and structures that make networks work, ahead of 4.2, Network issues and communication.

The router

You need to know the operation and purpose of a router, covering three specific functions: connecting networks and devices to the internet, storing computer addresses (so it knows where to send incoming data), and routing data packets – directing each packet of data along an appropriate path toward its destination. A router sits at the boundary between a local network and the wider internet, making it the single device most commonly named in questions about how a home or school network reaches the internet.

Common network devices

Beyond the router, you need to know the purpose of network interface cards (NIC), hubs, bridges, and switches. An NIC is the hardware that lets an individual device connect to a network at all. A hub broadcasts incoming data to every device connected to it, regardless of which device the data is actually intended for – simple but inefficient. A switch improves on this by learning which device is connected to which port and sending data only to the intended recipient, making better use of network capacity. A bridge connects two separate network segments together so they function as one combined network.

Wi-fi and Bluetooth

You need to know the uses of wi-fi and Bluetooth, how to connect a device to a network using each, and the similarities and differences between them. Both are wireless connection methods, but they serve different purposes: wi-fi typically connects a device to a wider network (and through it, the internet) over a larger range, while Bluetooth typically connects two devices directly to each other over a much shorter range, commonly for peripherals such as headphones or a wireless keyboard, without needing a network infrastructure in between.

Cloud computing

You need to know the characteristics, uses and issues relating to cloud computing, including how data is stored, managed and shared this way, and the advantages and disadvantages of cloud storage compared with other storage methods. Cloud storage’s main advantages are accessibility (data can be reached from any internet-connected device) and reduced reliance on local storage hardware; its main disadvantages are dependency on a working internet connection to access the data at all, and reliance on a third-party provider for the data’s security and availability.

Network environments: extranet, intranet, and the internet

You need to know the characteristics, uses and purpose of an extranet, an intranet, and the internet, and the differences and similarities between them. An intranet is a private network, internal to a single organisation, accessible only to its own members. An extranet extends a private network to allow controlled access for specific external parties, such as trusted suppliers or customers, while still restricting general public access. The internet is the global, publicly accessible network that connects networks worldwide. The shared thread across all three is the same underlying networking technology; what differs is who is permitted to access it.

Network types: LAN, WLAN and WAN

You need to know Local Area Network (LAN), Wireless Local Area Network (WLAN), and Wide Area Network (WAN), and the differences between them. A LAN covers a small geographic area, typically a single building or site, connected by cabling. A WLAN is functionally the wireless equivalent of a LAN, covering a similar small area but using wireless connections (such as wi-fi) instead of cables. A WAN covers a much larger geographic area, often connecting multiple LANs across different sites, cities or countries – the internet itself is the largest example of a WAN.

A worked scenario

A school wants students to access shared coursework files from any of its classrooms, its library, and their own homes, while also letting a small number of approved textbook suppliers upload new resources directly. The classroom-to-library connection within the school building is best served by a WLAN (wireless, single site). Reaching the internet from that network requires a router, handling address storage and packet routing to and from the wider internet – itself a WAN. Student access to shared coursework from home could be met either by cloud storage (accessible from any internet-connected device without needing to reach the school’s own servers directly) or by a remotely-accessible intranet-style system. The supplier upload access is the clearest case for an extranet: controlled, limited external access to specific resources, rather than a fully public internet system or a fully closed internal-only intranet. Working through a combined scenario like this, rather than revising each term in isolation, is a good check that the distinctions above are genuinely understood rather than just memorised.

How to approach it

Learn the router’s three named functions (connecting to the internet, storing addresses, routing data packets) as a specific list rather than a vague “connects to the internet” answer, since exam mark schemes credit each function separately. Practise distinguishing hub, switch and bridge by what happens to incoming data at each device – broadcast to all (hub), directed to the intended recipient only (switch), or joining two segments (bridge) – since these three are frequently confused with each other. For network types, anchor LAN, WLAN and WAN to a concrete scale (a single building, the same building wirelessly, and multiple sites) rather than abstract definitions, and be ready to classify a described network (for example, “a school connects its three campuses across a city”) using the correct term with a stated reason.

Official syllabus

Cambridge International, Cambridge IGCSE Information and Communication Technology (0417) syllabus for 2026, 2027 and 2028: official syllabus PDF, Subject content, section 4.1 “Networks”. Verified 2026-09-02.