User Response Time is a sum of the averages of the following four metrics:

“Connection Setup Time [msec]” + “Server Response Time [msec]” + “Total Payload Transfer Time [msec]” + “Total Retrans Delay [msec]”.

User Response Time estimates the average time for an application to process a TCP data request, and thus is a good measure of end-user response time.

Total Retrans Delay composition can be viewed as Request Retrans Delay [msec] and Response Retrans Delay [msec] to isolate the source of the delay.