Multiparameter Qos Admission Control for Atm Queues with Partial Buuer Sharing Mechanism

In this paper, we present an admission control technique for mixed real-time and nonreal-time tra c in nite length queues with PBS cell loss control. Real-time connections have both delay and loss constraints while non-real-time connections are only subject to cell loss constraints. We propose to provide each type of tra c with a separate capacity subregion with di erent QoS bounds. We introduce the concept of virtual e ective bandwidth (VEB) for the tra c source inside the capacity subregion. VEB of the source depends on the tra c descriptors of the source, QoS bound for a given tra c class, and on the sum of average arrival rates of connections from other tra c classes. In the case of one capacity region, virtual e ective bandwidth of the connection is equal to the its e ective bandwidth. Expressions of virtual e ective bandwidth for each speci c capacity subregion under di erent QoS limits have been derived. These limits include average queue length, the second derivative of queue length probability generating function (PGF) which constrains both delay and delay jitter, aggregate tra c losses, and target connection losses. The expressions show the relationships between the QoS limits given an (virtual) e ective bandwidth. Based on these expressions, we propose an admission control algorithm which can manage separate capacity subregions with di erent types of tra c and di erent QoS requirements. The bandwidths of capacity subregions can be dynamically adjusted to satisfy the instantaneous needs of real-time and non-real-time tra c.