Bandwidth · Latency · Interference · Number of Users · Error Rate
CSZoneEdexcel GCSE Computer Science 1CP2
Bandwidth
The Capacity of the Connection
Bandwidth is the maximum amount of data that can be transmitted per second, measured in Mbps or Gbps. Higher bandwidth = more data transferred = faster network. It is like the width of a road — more lanes = more traffic.
Bandwidth is shared among users — more users on the same connection reduces effective speed per person
Fibre optic offers much higher bandwidth than copper ethernet; Wi-Fi varies by standard
Bandwidth ≠ speed — latency also matters for real-time applications
Latency & Interference
Delay and Signal Degradation
Latency: the delay between sending data and it arriving at the destination, measured in milliseconds (ms). Critical in online gaming, video calls, and real-time control systems.
Interference: wireless signals can be disrupted by physical obstacles (walls), other wireless devices, microwave ovens, and competing networks on the same channel.
Distance also affects performance — signal strength decreases over distance (attenuation)
Other Factors
What Else Slows a Network?
Number of users: more devices sharing the same connection = less bandwidth per device
Type of transmission medium: fibre > ethernet > Wi-Fi in terms of speed and reliability
Error rate: data that arrives corrupted must be retransmitted — increases effective latency and reduces throughput
Network hardware: older/cheaper switches and routers can bottleneck throughput even with fast cables
Exam Practice
Have a go at this question
Edexcel-style question
Give two factors that could affect the performance of a wireless network in a school and explain their impact.
4 marks
Number of users: many devices sharing the WAP reduces bandwidth per device [1+1]. Interference: walls and other wireless devices on the same channel reduce signal quality and cause retransmissions, slowing the network [1+1].
Key Takeaways
What to Remember
Bandwidth: max data per second (Mbps/Gbps); shared between users
Latency: delay in ms; critical for gaming and video calls
Interference, number of users, hardware quality, and distance all affect performance
High bandwidth + low latency = ideal network; fibre delivers best of both