In (tele)communication networks, latency is a term often identified with the term delay. Generally speaking, latency is a measure of delay. This is measured as a round-trip delay – the time taken for data to get to the destination and back in the form of acknowledgment. There are four main types of network delays: delay due to frame/packet processing in network nodes (processing delay), delay that the frame/packet spends in the queue (queuing delay), delay caused by the handover of the frame/packet on the link (transmission delay) and the propagation delay, i.e. the time needed for the frame/packet to reach the destination.
Thus, latency is the sum of all end-to-end communication delays in the network or in its individual segment. In 5G mobile networks, the latency in the radio access network should be below 1 ms.