OCR · GCSE · Computer Science
Course version: J277 · Version from Sept 2022
Networks and topologies: Star and Mesh network topologies
A network topology is the arrangement of devices and connections in a network.
Checked against the OCR J277 specification on .
- Point 6 of 6
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
A network topology is the arrangement of devices and connections in a network. In a star topology, every device connects to a central node, usually a switch or hub; all traffic passes through that central device, which makes faults easier to isolate but creates a single point of failure. In a mesh topology, devices connect to multiple other devices, so data can take alternative routes; a full mesh connects every device to every other device, while a partial mesh connects some devices by more than one path. Mesh networks are robust and can spread traffic, but they need more cabling or wireless links and are more complex and costly to install and manage. Star networks are simpler to add devices to and to troubleshoot, but performance and availability depend on the central node.
What earns the marks
- A topology describes how devices in a network are arranged and connected.
- In a star topology, each device connects to a central node such as a switch, and all data passes through that central node.
- A star topology is easy to add devices to and faults are easier to isolate, but the central node is a single point of failure.
- In a mesh topology, devices connect to multiple other devices so data can be routed along alternative paths.
- A full mesh connects every device to every other device, while a partial mesh connects only some devices by multiple paths.
- Mesh topologies are robust because there is no single point of failure, but they require more connections and are more complex and costly.
Common mistakes and how to put them right
Saying a star topology has no central device.
Put it right by identifying the central switch or hub that all devices connect to.
Confusing a full mesh with a partial mesh.
Put it right by stating that a full mesh connects every device to every other device.
Claiming mesh networks are always cheaper.
Put it right by explaining that extra connections increase cost and complexity.
Exam tips
- Sketch the topology and label the central node or the multiple links to support your written answer.
- Compare star and mesh directly using points such as cost, fault tolerance and ease of adding devices.
- Use the phrase single point of failure accurately when discussing the central node in a star topology.
Try the lesson
The start of the Networks and topologies: Star and Mesh network topologies lesson, made from checked teaching notes for this specification point.
Have a go first
In a star network topology, which device connects all of the other devices together?
Listen
A network topology is the arrangement of devices and connections in a network. In a star topology, every device connects to a central node, usually a switch or hub; all traffic passes through that central device, which makes faults easier to isolate but creates a single point of failure. In a mesh topology, devices connect to multiple other devices, so data can take alternative routes; a full mesh connects every device to every other device, while a partial mesh connects some devices by more than one path. Mesh networks are robust and can spread traffic, but they need more cabling or wireless links and are more complex and costly to install and manage. Star networks are simpler to add devices to and to troubleshoot, but performance and availability depend on the central node. A strong answer earns marks for these points. A topology describes how devices in a network are arranged and connected. In a star topology, each device connects to a central node such as a switch, and all data passes through that central node. A star topology is easy to add devices to and faults are easier to isolate, but the central node is a single point of failure. In a mesh topology, devices connect to multiple other devices so data can be routed along alternative paths. A common slip: Saying a star topology has no central device. Instead, identifying the central switch or hub that all devices connect to. Exam tip: Sketch the topology and label the central node or the multiple links to support your written answer.
Key words
Say what each word means before you turn the card.
Network topology
Try answering aloud or in your head before turning the card.
Star topology
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Mesh topology
Try answering aloud or in your head before turning the card.
Full mesh
Try answering aloud or in your head before turning the card.
See every definition
- Network topology
- The arrangement of devices and connections in a network.
- Star topology
- Every device connects to a central node, usually a switch or hub, and all traffic passes through that central device.
- Mesh topology
- Devices connect to multiple other devices, so data can take alternative routes.
- Full mesh
- A mesh in which every device connects to every other device.
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