What term describes the measure of usable data transferred over a given period of time at the OSI physical layer?

The term that accurately describes the measure of usable data transferred over a given period of time at the OSI physical layer is goodput. Goodput specifically refers to the amount of useful data that is successfully delivered to the destination, excluding any protocol overhead, retransmissions, or errors. This makes it a more precise measure of effective data transfer as it focuses on the actual data payload being successfully communicated, as opposed to total data sent which might include overhead.

Goodput allows for a clearer understanding of the performance of a network. For instance, while bandwidth indicates the maximum capacity of a connection, it might not reflect how much of that capacity is effectively utilized for meaningful data, which is why goodput is a critical metric in evaluating network efficiency and performance.

In contrast, throughput measures the total data transferred, including both useful data and any additional overhead. Latency refers to the delay experienced in the transmission of data, which is unrelated to the actual amount of usable data passed in a given timeframe. Bandwidth indicates the maximum potential data transfer rate of the network link but does not account for the actual performance.