AN EVALUATION OF ROUTING AND ADMISSION CONTROL ALGORITHMS FOR REAL-TIME TRAFFIC IN PACKET-SWITCHED NETWORKS

Networks supporting real-time traffic employ controlled admission of calls to ensure an acceptable quality of service. In this work, we investigate how routing and admission control interact in determining overall performance. We propose and evaluate the use of routing algorithms which take into account the constraints imposed by the admission control algorithms. These algorithms are of the least loaded path type and are found to perform better than sequential routing type algorithms which have been suggested elsewhere. We show that the new algorithms decrease call blocking probability and increase network utilization. The amount of improvement depends on such factors as the admission control function, the traffic mix, and the QOS constraints. Two deterministic methods of Call Admission Control: Earliest Due Date and Stop&Go are evaluated. The effect of lossy source traffic shaping on routing is studied. The interaction and relative importance of routing, admission control, and traffic shaping is examined.