Computing - Topologies
AQA Computer Science 2022
See Also
Networks and topologies
What is a computer that is not connected to any other devices called?
A standalone computer.
What is a Local Area Network?
Two or more computers connected together within a small geographical area.
What is a bus network?
An arrangement where nodes are connected in a daisy chain by a single central communications channel.
What is a star network?
An arrangement where a central node or hub provides a common connection point for all other nodes.
In a bus network, what is the main limitation of how data can be sent?
It can only be sent in one direction at a time only.
In a bus network, why can only one computer transmit data successfully at a time?
Because otherwise you’d get data collisions.
CSMA/CD and collisions
What does CSMA/CD detect?
When two nodes are attempting to transmit data simultaneously.
How does CSMA/CD prevent nodes transmitting data simultaneously?
Both nodes cease transmission and wait a random amount of time before reattempting.
NICs, MAC addresses and switches
How does a switch know which device to send packets to?
It stores the MAC addresses of the devices on the network.
Why is a switch more secure than a hub?
Because it doesn’t send every packet to every device.
Physical vs logical topology
What is the physical topology of a network?
How the devices are physically connected.
What is the logical topology of a network?
How the devices communicate across the physical topologies.
How could you make a physical star network behave as a logical bus network?
Using a bus protocol and physical switching.
A bus network.