a) What is a computer network topology? [1] b) Write any four types of computer network topologies. [4]

a) Computer Network Topology

A computer network topology refers to the arrangement or layout of various elements (such as computers, printers, and servers) in a computer network. It defines how devices are interconnected, the physical or logical structure of the network, and how data is transmitted between them. Topology can be categorized into physical topology (how devices are physically connected) and logical topology (how data flows between devices).

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b) Four Types of Computer Network Topologies

1. Bus Topology

• All devices are connected to a single communication line (bus).
• Data is transmitted in both directions along the bus.
• Simple and cost-effective but prone to network failure if the main cable breaks.
• Example: Ethernet networks (10BASE2).

Diagram of Bus Topology showing devices connected to a single cable (Image: Bakshi41c, CC BY-SA 3.0, via Wikimedia Commons)

2. Star Topology

• All devices are connected to a central hub, switch, or router.
• Data flows through the central device, which manages communication.
• Easy to install, maintain, and expand; less prone to failure (only the central hub affects the network).
• Example: Home Wi-Fi networks, office LANs.

Diagram of Star Topology showing devices connected to a central hub (Image: Umapathy, CC BY-SA 3.0, via Wikimedia Commons)

3. Ring Topology

• Devices are connected in a closed loop, where each device acts as a repeater.
• Data travels in one direction (clockwise or counterclockwise).
• Efficient for data transmission but vulnerable to failure if one node breaks.
• Example: Token Ring networks (IBM Token Ring).

Diagram of Ring Topology showing devices connected in a closed loop (Image: Kiril Simeonovski, CC BY-SA 4.0, via Wikimedia Commons)

4. Mesh Topology

• Every device is connected to every other device (full mesh) or to a few others (partial mesh).
• Provides high reliability and fault tolerance (if one link fails, others take over).
• Expensive and complex to implement.
• Example: Military networks, underwater sensor networks.

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