Circuit allocation and overload control in a hybrid switching system

A hybrid switching system which provides integrated packet and circuit switching is considered. The framing structure is based on position multiplexing of the isochronous slots. The switch capacity is dynamically allocated to meet the demand of the synchronous circuits. Due to some wastage inherent in the framing structure, not all of the remaining capacity is available for the packet switched traffic. In order to evaluate the packet capacity, we derive the statistics of the effective bandwidth utilized by the isochronous traffic. Three circuit allocation policies are considered: repacking, first-fit and first-fit involving circuit blocking policy. The analysis takes into consideration the waste created by these policies. Numerical results are presented to compare between the efficiency of these schemes, and to demonstrate, in each case, the effect of circuit loading on the effective capacity utilized by the isochronous traffic which in turn determines the packet capacity. © 1989.