1. Is bandwidth the same as latency?
- Yes
- Only on Wi-Fi
- No
Check the answer and reasoning
No
Bandwidth is capacity per unit time; latency is delay.
CS / AS level
Networks, communication and protocols
Network hardware, addressing and protocols cooperate to carry messages. Circuit switching reserves a path; packet switching shares links and permits packets to travel separately.
Learning objectives
- Explain networks, communication and protocols using a concrete example.
- Apply the worked method and justify each step.
- Recognise the limitation described in the final check.
The big idea
Network hardware, addressing and protocols cooperate to carry messages. Circuit switching reserves a path; packet switching shares links and permits packets to travel separately.
Layering separates responsibilities, from physical transmission to applications. Bandwidth describes a rate capacity, while latency is delay; security and congestion influence the observed performance.
Equations and relationships
time ≈ data size / transfer rate
Ideal transmission time with compatible bit units, excluding overhead and delay.
Worked example
At 8 Mbit/s, how long does 16 Mbit take ideally?
Follow the solution
16/8=2 seconds before protocol overhead and other delays.
Investigate and explain
Predict the worked result before calculating. Change one input, record the new result, and explain which assumptions still hold.
Use the prediction activity below; a local model appears only where it supports this topic.
Check your understanding
2. At 8 Mbit/s, how long does 16 Mbit take ideally?
- 2 s
- 128 s
- 0.5 s
Check the answer and reasoning
2 s
16/8=2 seconds before protocol overhead and other delays.
3. Why use protocol layers?
- To guarantee no packet loss
- To separate responsibilities and interfaces
- To remove all addresses
Check the answer and reasoning
To separate responsibilities and interfaces
Layering supports modular design but does not itself guarantee reliable delivery.