Round Trip Time, or RTT, refers to the amount of time it takes for a signal to travel from a particular terrestrial system to a designated satellite and back to its source. Round Trip Time is also referred to as Round Trip Delay.
There are several factors that affect Round Trip Time. Generally, the speed of light limits Round Trip Time. The type of satellites used also affect Round Trip Time. Geostationary satellites have the longest Round Trip Time when transferring signals. On the other hand, Low Earth Orbit (LEO) satellites have the shortest Round Trip Time.
The concept of Round Trip Time is also applied in data transfers between computers. In this context, Round Trip Time is the amount of time required by a computer to send data packets to a remote computer and back again to the original source. Several factors affect the Round Trip Time for computers. These include the data transfer rate of the Internet connection of the source computer, the physical distance between the source and the destination, the amount of traffic currently present on the local area network, and the number of nodes or computers between the source and destination.
In both cases, Round Trip Time can range from a few seconds to a few milliseconds. The better the transfer rate and the nearer the two units, the faster the Round Trip Time. Also, Round Trip Time incorporates a theoretical minimum which comes from the premise that it can never be lower than the time the signals or data require to propagate within the transmission media.