Measure of the responsiveness of a network, often expressed as the round-trip time (in milliseconds); that is, the time between initiating a network request and receiving a response. High latency tends to have more impact than bandwidth on the end-user experience in interactive applications, such as Web browsing. Low latency is required for many next-generation IP applications, such as VoIP, video telephony and PTT. See also round-trip time (RTT).