Quality of service (QoS), in network and telephony, parlance has both specific and less precise but more practical meanings. In general, quality of service can be viewed as measuring the performance of a network or telephone service, thereby providing an indication of its quality.

A network key performance indicator (KPI) is a measurement and a benchmark to achieve optimal network performance goals. To support these goals, measuring actual performance against the KPI goals helps the network team make decisions to improve and sustain network performance and service levels and meet the KPI objective.