Analysis and performance comparisons are presented for synchronous discrete-time queuing systems operating under a message waiting-time or delay-time constraint. Four different system admission and preemption policies are investigated. Under either a wait-time constraint or a delay-time limit, either newly arriving messages are always admitted (and then properly dismissed if their required residence limits are not met) or a determination is made upon arrival on whether the new message can be served to completion within its required time limit, and only then is this message admitted. The delay-throughput performance of these admission and service-preemption policies is investigated and compared for synchronous discrete-time communications and processing systems modeled as a single-server Geom/G/1 discrete-time queuing system. Such models are used to describe various multiplexing and demand-assigned (reservation-based) multiple-access communication network systems operating under message delay limits.>

The authors carry out message delay and system throughput analysis for communication and telecommunications system applications which require the use of finite-capacity service systems using preemptive buffering (PB) disciplines. Such systems are of particular importance in situation where it is essential to provide short (and at times, bounded) message waiting-time delays, for messages which are selected for service. The authors analyze and compare the performance of such service systems, modeling them as finite capacity M/G/1/N queueing systems and using the service/buffering policies first-come-first-served/nonpreemptive buffering (FCFS/NPB), FCFS/PB, and last-come-first-served/preemptive buffering (LCFS/PB). They evaluate the performance tradeoffs offered by these policies, as they relate to the mean and variance of the waiting times of messages which are eventually served or eventually rejected/preempted.>