Reservation Techniques in an OpMiGua Node

An OpMiGua node integrates a packet switch for low priority traffic and a circuit switch for high priority traffic. Both traffic classes share the same input and output ports using time division multiplexing, but absolute priority is given to circuit switched packets. The circuit switched packets do not experience contention at output ports and are not subject to delay jitter; hence a guaranteed service class is created. Previous studies of OpMiGua nodes have used one of two reservation techniques to assure priority; either a time-window approach or a preemptive approach. This article introduces two new reservation techniques and investigates advantages and drawbacks associated with the four techniques. It is shown that each reservation technique is associated with specific loss mechanisms and methods to reduce their influence are proposed. Simulation results demonstrate that the choice of reservation technique is highly influenced by the relative share and length of high priority packets.