Joint Scheduling and Admission Control for ATS -

A joint scheduling and admission control algorithm is presented for Asynchronous Time-Sharing (ATS)-based switching nodes carrying real-time traac. Systems based on ATS guarantee quality of service, at both the levels of cells and calls, for three well-deened traac classes. A mechanism is outlined by which an admission control strategy can be tailored to a particular mix of traac by making use of high-level information from the scheduler. This mechanism is based on a principle of separation between scheduling and admission control. A linear programming formulation is used to nd the admission control policy which will maximize the expected system utility while maintaining the guaranteed quality of service. The admissible load region is introduced as a means of quantifying the capacity of a switch under the QOS constraints at the cell and call levels. Numerical calculations for a single MAGNET II switching node carrying two classes of real-time traac are used to illustrate the eeects of diierent scheduling and admission control policies on both the expected utility and the admissible load region.