# Computing - Topologies

> Source: https://ollybritton.com/notes/a-level/computing/topics/topologies/ · Updated: 2021-02-01 · Tags: computing, networking

### See Also
- [Computing - Networking](https://ollybritton.com/notes/a-level/computing/topics/networking/)

### Flashcards
##### What is a computer that is not connected to any other devices called??
A standalone computer.

##### What's the name for two or more computers connected together??
A network.

##### 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 trasmit data successfully at a time??
Because otherwise you'd get data collisions.

##### What does CSMA stand for??
Carrier Sense Multiple Access

##### What does CSMA/CD stand for??
Carrier Sense Multiple Access with Collision Detection.

##### What does CSMA/CD detect??
When two nodes are attempting to transmit data simultaneously.

##### How does CSMA/CD prevent nodes trasmitting data simultaneously??
Both nodes cease transmission and wait a random amount of time before reattempting.

##### What does NIC stand for??
Network Interface Card

##### What is the unique address hardcoded on a NIC called??
A MAC address.

##### What does MAC stand for??
Media Access Control

##### 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.

##### ![PHOTO CONFUSING NETWORK](confusing-network.png) Is this a bus or a star network??
A star network.

##### 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 topolgies.

##### How could you make a physical star network behave as a logical bus network??
Using a bus protocol and physical switching.

##### ![PHOTO CONFUSING NETWORK](confusing-network.png) What is the logical topology of the three computers on the left??
A bus network.

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