Editing Round-trip delay (section)

{{short description|Time required to receive a response to a query across a communication system}}

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 acknowledgement of that signal having been received. This time delay includes [[Signal propagation delay|propagation times]] for the paths between the two [[communication endpoint]]s.<ref>{{citation |title=Round-trip delay time |url=http://www.its.bldrdoc.gov/fs-1037/dir-031/_4641.htm |access-date=2021-05-29 |archive-url=https://web.archive.org/web/20211017172734/https://www.its.bldrdoc.gov/fs-1037/dir-031/_4641.htm |location=[[Boulder, Colorado]] |publisher=[[National Telecommunications and Information Administration]]'s Institute for Telecommunication Sciences |archive-date=2021-10-17}}</ref> In the context of computer networks, the signal is typically a [[data packet]]. RTT is commonly used interchangeably with '''ping time''', which can be determined with the [[ping command]]. However, ping time may differ from experienced RTT with other protocols since the payload and priority associated with [[Internet Control Message Protocol|ICMP]] messages used by ping may differ from that of other traffic.

[[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.