FIFO/FILO

Abbreviated as FIFO and FILO, first-in first-out and first-in last-out are concepts in telecommunications that apply to communication bridges, switches, routers, and computer networks. FIFO indicates that parties or entities in a queue leave the queue in the same order in which they have arrived. Telecommunications technology requires that data packets be held en route to a destination and then assigned based on entry to the queue. FILO indicates that entities will leave a queue in the reverse order from which they arrived. In telecom data processing, the FILO queuing structure will prioritize the entity or party that arrived first in the queue as opposed to the one that arrived last, giving the first arriving party first priority in data structure or telephone line access.