Payload rate refers to which of the following?

• A. The total data including overhead.
• B. The raw data rate of the line.
• C. The data useful for the application, excluding overhead.
• D. The rate at which errors are detected.

Answer: (C)

Payload rate is the amount of useful data delivered to the application per unit time, excluding overhead such as framing, headers, and error-check bits. It captures the actual information the application can use, not the extra bits needed to move that information across the link. This is why it best fits telemetry, where you care about how quickly the meaningful telemetry data arrives, not the total on-the-wire bits. For example, a link might operate at 1000 kilobits per second, but if 200 kilobits per second are overhead, the payload rate is 800 kilobits per second. The raw data rate of the line would be the total line capability including overhead, and the rate at which errors are detected is a separate metric related to error checking, not the amount of useful data carried.