As long as the data throughput is within the specified value, the transmission link meets the required performance. However, if the value falls below the required data throughput, the packet loss rate increases during packet transmission and the transmission quality decreases. This has a particularly strong effect on packet-switched real-time applications such as Internet telephony, where the quality of service is reduced.
To evaluate the data throughput, the user data transmitted without errors within a certain period of time is measured and set in relation to the total transmitted data. The data throughput is thus calculated from the quotient of the data bits transmitted without errors to the sum of all transmitted bits, based on a specified period of time. It is expressed, for example, in bit/s, characters/s or data packets/s. The effective throughput, i.e. the net data throughput, results from the total throughput minus the overhead that reduces the data throughput due to error correction methods, addresses, etc.