EnglandComputer ScienceSyllabus dot point

How are computers connected into networks, what topologies and models are used, and what hardware makes a network work?

Networks: LANs and WANs, network topologies (bus, star, mesh), the client-server and peer-to-peer models, and the hardware that connects a network (network interface cards, switches, routers and the role of the internet).

An Eduqas Component 2 answer on networks: the difference between LANs and WANs, the bus, star and mesh topologies with their pros and cons, the client-server versus peer-to-peer models, and the hardware (NICs, switches, routers) that connects a network.

Generated by Claude Opus 4.813 min answerUpdated 2026-06-02

Reviewed by: AI editorial process; not yet individually human-reviewed

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Quick answer

A local area network (LAN) covers a small geographical area (a home, school or office), usually owned by one organisation; a wide area network (WAN) spans a large area (cities, countries) using infrastructure often leased from third parties, the internet being the largest WAN. Networks are arranged in topologies: a bus connects all devices to one shared backbone cable (cheap but fails if the backbone breaks); a star connects every device to a central switch (resilient to single failures and fast, but needs more cabling and depends on the switch); a mesh interconnects devices with multiple paths (very resilient but expensive). Two models: client-server, where dedicated servers provide resources to clients (central control, security and backup, but needs a powerful server); and peer-to-peer, where every device is equal and shares directly (cheap and simple, but no central management). Key hardware: a network interface card (NIC) connects a device to the network, a switch forwards data within a network to the addressed device, and a router connects different networks and routes packets between them.

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What this dot point is asking
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What this dot point is asking

Eduqas wants you to distinguish LANs and WANs, describe the bus, star and mesh topologies with their pros and cons, compare the client-server and peer-to-peer models, and describe the hardware (NICs, switches, routers) that connects a network.

The answer

LANs, WANs and topologies

Key fact

A LAN covers a small area (a building or site), is typically owned and managed by one organisation, and uses its own cabling or Wi-Fi. A WAN connects networks over a large geographical area, using long-distance infrastructure (often leased), with the internet as the global example. Topologies describe the layout: a bus uses one shared backbone cable (low cost and little cabling, but the whole network fails if the backbone breaks, and collisions slow heavy traffic); a star connects each device to a central switch (one cable or device failing does not affect the rest, and performance is good, but it needs more cabling and the switch is a single point of failure); a mesh gives multiple paths between devices (highly resilient, rerouting around failures, but expensive in cabling for a full mesh).

Client-server and peer-to-peer models

Network hardware

Design a small office network

A small office of 12 computers needs shared files, central security and reliable internet access. Recommend a topology, model and hardware.

step 1: Choose the model

Central security, shared files and backup point to a client-server model: a server holds the files and handles authentication, giving the office central control.

step 2: Choose the topology

A star topology connects each computer to a central switch: it performs well, and one failed cable or PC does not bring down the others, important for a working office.

step 3: Specify the hardware

Each computer uses its built-in NIC; a switch connects them into the LAN; a router connects the LAN to the internet and routes outbound packets, providing the reliable internet access required.

step 4: Note the trade-off

This costs more than a peer-to-peer star (a server plus the switch), but delivers the central security, backup and shared storage the office needs, a justified choice for 12 users.

Examples in context

A home network is typically a star (devices to a combined router/switch) using a client-server relationship with internet servers but peer-to-peer for local file sharing. Schools and offices use client-server LANs for central control. The router in every home is exactly the device that connects the LAN to the internet WAN. This dot point sets up the next module's data transmission topic, the protocols, TCP/IP stack and packet switching that govern how data actually moves across these networks.

Try this

Q1. State one difference between a LAN and a WAN. [1 mark]

Cue. A LAN covers a small area (one site, one organisation); a WAN spans a large geographical area (often leased infrastructure, like the internet).

Q2. Give one advantage and one disadvantage of a star topology. [2 marks]

Cue. Advantage: a single failed cable or device does not affect the others (and good performance). Disadvantage: more cabling, and the central switch is a single point of failure.

Q3. What is the role of a router? [1 mark]

Cue. It connects different networks together and routes data packets between them using IP addresses.

Exam-style practice questions

Practice questions written in the style of WJEC Eduqas exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

Eduqas 20206 marksDescribe the bus, star and mesh network topologies, giving one advantage and one disadvantage of each.

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Bus (up to 2 marks): all devices share a single central cable (the backbone). Advantage: cheap and simple to set up with little cabling. Disadvantage: the whole network fails if the backbone breaks, and performance falls with heavy traffic (data collisions).

Star (up to 2 marks): all devices connect to a central switch or hub. Advantage: a single device or cable failing does not affect the others, and it performs well. Disadvantage: more cabling is needed and the central switch is a single point of failure.

Mesh (up to 2 marks): devices are interconnected with multiple paths between them. Advantage: very resilient, as data can take an alternative route if a link fails. Disadvantage: expensive due to the large amount of cabling/connections (in a full mesh).

Markers reward a correct description of each topology with one valid advantage and one valid disadvantage.

Eduqas 20225 marksExplain the difference between the client-server and peer-to-peer network models, and describe the role of a router and a switch.

Show worked answer →

Client-server versus peer-to-peer (up to 3 marks): in a client-server model, dedicated servers provide resources and services (files, printing, authentication) to client machines that request them; it offers central control, security and backup but needs a powerful server. In peer-to-peer, every device is equal and shares its own resources directly with others; it is cheaper and simpler with no dedicated server, but lacks central management and security.

Router (up to 1 mark): connects different networks together (for example a home network to the internet) and directs (routes) data packets between them using IP addresses.

Switch (up to 1 mark): connects devices within a single network and forwards data only to the specific device it is addressed to, using MAC addresses.

Markers reward the dedicated-server versus equal-peers distinction, the router connecting networks/routing by IP, and the switch connecting devices within a network/forwarding by MAC.

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Sources & how we know this

WJEC Eduqas GCE AS/A Level Computer Science specification (from 2015) — Eduqas (2015)