Optimal policies for integrating heterogeneous services on isdn channels

Abstract

A technique for the classification and evaluation of hierarchical access integration policies of ISDN channels is proposed. The essence of the basic control decisions based on several parameters of the servers and channel is captured in a single priority-based-layered model of multiple queues. We solve for the resulting delay of different policies and investigate the performance in one tractable limit of this model. Using our understanding of the problem parameters and their interaction, we propose a number of heuristic policies for the general model. The results of the general problem complexity investigations suggest the use of simulation models. Problem parameters considered are channel acceptable access delay value, number of servers needed, and flow duration time of a request. Preemptive and non-pre-emptive policies on queued traffic are considered. Performance considers average delay, delay variation and channel utilization. Simulation data on these policies suggest that policies that favour shorter services given better overall delay over a wide range of system parameters. Policies that favour longer and broadband services, on the other hand, show better quality and smaller delay variation.