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Network topologies
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A topology is the layout of a network: how the devices are connected. Each layout has its own strengths and weaknesses.
Bus
All devices connect to one main cable, the backbone, with a terminator at each end.
Cheap and easy to set up, needing little cable.
Only one device can send at a time, so data collisions happen and it slows with heavy traffic. If the backbone breaks, the whole network fails.
Cheap and easy to set up, needing little cable.
Only one device can send at a time, so data collisions happen and it slows with heavy traffic. If the backbone breaks, the whole network fails.
Star
Every device connects to a central switch.
If one cable fails, only that device is affected. Easy to add devices. Fewer collisions, so performance is good.
Needs more cable, and if the switch fails the whole network stops.
If one cable fails, only that device is affected. Easy to add devices. Fewer collisions, so performance is good.
Needs more cable, and if the switch fails the whole network stops.
Mesh
Devices connect to several others, so there are many routes. In a full mesh every device connects to every other.
Very reliable: if one link fails, data takes another route.
Expensive and complex, with lots of connections. Parts of the internet use a mesh.
Very reliable: if one link fails, data takes another route.
Expensive and complex, with lots of connections. Parts of the internet use a mesh.
A bank cannot afford its network to go down. Which topology suits it best and why?
- Mesh gives many routes between devices.
- If a link fails, data is rerouted, so the network keeps working.
Answer: Mesh, because there are many routes and no single point of failure
Bus: one backbone, cheap, but collisions and a single point of failure. Star: central switch, reliable and fast, but the switch is a single point of failure. Mesh: many routes, very robust but expensive.
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