Which phenomenon describes the delay variation in packet arrival times within a network?

• A. Throughput
• B. Latency
• C. Bandwidth
• D. Jitter

Answer: (D)

Delay variation in packet arrival times across a network is called jitter. Jitter specifically describes how much the timing of packet arrivals fluctuates from one packet to the next. Latency, by contrast, refers to the overall time it takes for a single packet to travel from sender to receiver, including processing and propagation delays. Bandwidth is about the maximum amount of data that can be transmitted in a given time, and throughput is the actual data rate achieved, which can be less than bandwidth due to network conditions. Jitter matters for real-time communications and imaging data transfer because irregular arrival times can cause playback glitches or buffering, even if the average delay remains reasonable. For example, if packets arrive at varying intervals like 18 ms, 22 ms, and 15 ms instead of a steady interval, that variation is jitter.