An Evaluation of Routing and Admission Control Algorithms for Multimedia Tra c in Packet-Switched Networks

Support for real-time multimedia applications is becoming an essential requirement for packetswitched networks. In this work, we investigated how routing and admission control in uence the performance of packet-switched networks. We propose and evaluate the use of routing algorithms which take into account the constraints imposed by the admission control algorithms. Routing algorithms proposed elsewhere in literature are also evaluated. We show that the new algorithms decrease call blocking probability and increase network utilization. The amount of iprovement depends on such factors as the admission control function, the tra c mix, and the QOS constraints. We evaluated two deterministic methods of Call Admission Control: Earliest Due Date and Stop&Go. We studied the e ect of lossy source tra c shaping on routing. The interaction and relative importance of routing, admission control, and tra c shaping was also studied. Technical Areas : Routing and control of congestion, admission and ow control This work was supported by the Air Force O ce of Scienti c Research Under Grant F49620-92-J-0441. Rampal: An Evaluation of Routing & Admission Control : : : 1 Run-time packet scheduling & Flow control Routing & Bandwidth Allocation Call level Admission Control (insuff. bw) Blocked Calls Blocked Calls (CAC rejn) Admitted Calls Incoming Calls Figure 1: Interaction Between Di erent Tra c Management Functions