Meaning – The term round-trip message delay, refers to the sum of the one-way message delays from the origin to the destination and back, not including application processing time.
Round-trip time (RTT) is the duration in milliseconds (ms) it takes for a network request to go from a starting point to a destination and back again to the starting point. RTT is an important metric in determining the health of a connection on a local network or the larger Internet and is commonly utilized by network administrators to diagnose the speed and reliability of network connections.
End-to-end delay is the length of time it takes for a signal to travel in one direction and is often approximated as half the RTT.
Example of usage – “In telecommunications, round-trip delay (RTD) or round-trip time (RTT) is the amount of time it takes for a signal to be sent plus the amount of time it takes for an acknowledgment of that signal having been received.”