Describe circuit switching as a method of data transmission.

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2024). The mark or mark type is shown in brackets.

1. 3(a) One mark per mark point (Max 3)
2. 3(a) MP1 A dedicated circuit / channel is required
3. 3(a) MP2 The circuit is established before the transmission begins
4. 3(a) MP3 The circuit lasts for the whole of the transmission // The circuit is closed at the end of the transmission
5. 3(a) MP4 Data travels in a continuous stream along the same route
6. 3(a) MP5 Transmission is usually bidirectional.
7. 3(b) One mark for a benefit (Max 1)
8. 3(b) MP1 No need for data to be reassembled // data / frames arrive in the same order in which they were sent
9. 3(b) MP2 Suitable for real time transmission // fast data transfer rate
10. 3(b) MP3 The whole of the bandwidth is available
11. 3(b) One mark for a drawback (Max 1)
12. 3(b) MP4 No other transmission can use the same circuit when it is in use // Bandwidth can be wasted as it cannot be used by other messages
13. 3(b) MP5 Not secure // Can be intercepted as all data travelling along the same route
14. 3(b) MP6 If there is a problem with the route the transmission ends // No other route is available without first doing the setup
15. 3(b) MP7 The circuit is always there whether or not it's being used
16. 3(b) MP8 Can take time to set up before transmission starts.