Which measurement uses round-trip time to assess latency?

• A. Jitter
• B. Propagation delay
• C. Round-trip time
• D. Throughput

Answer: (C)

Latency is measured by the time it takes for a signal to travel to the destination and back. This measurement, known as round-trip time, is what tools like ping use: a probe is sent and the time until the reply arrives is recorded. This RTT reflects the total delay in both directions, plus any processing, queuing, and transmission delays at the endpoints, making it a practical gauge of end-to-end latency. Jitter is about how much latency varies between packets, not the single delay value. Propagation delay is only the one-way travel time through the path. Throughput concerns how much data can be transferred per unit of time, not the delay of a single exchange.