Cisco Enterprise Network Core Technologies (ENCOR) Practice Exam

Propagation delay refers to the time it takes for a signal to travel from its source to its destination through a medium, such as fiber optic cables, copper wires, or even wireless air. This time is influenced by the distance the signal must cover and the speed at which it travels through the medium, which is typically a fraction of the speed of light.

In essence, propagation delay is a crucial factor in understanding overall network performance, especially in long-distance communication, as it contributes to the total latency experienced in a network. Other types of delays, such as processing delay (time for routers to process the data), serialization delay (time required to put data packets onto the link), and delay variation (the inconsistency in packet arrival times), represent different aspects of overall latency but do not specifically measure the travel time of a signal through the network medium.