A Conservation Law for Single-Server Queues
08 May 1989
We derive a conservation law for G/GI/1 queues with general disciplines. We use this law to show that for the class of work-conserving disciplines which are nonanticipating with respect to the service times, FIFO minimizes (maximizes) the expected time in the system of a customer, when the service times are NBUE (NWUE).