Optimal control of preemptive systems with loss

We consider the problem of optimal preemption control in preemptive systems with loss. Based on a designed cost function composed by the following criteria: blocking cost function, preemption cost function, degradation cost function, and processing and signaling load cost function; we use the semi-Markov decision process framework as well as the value iteration algorithm to get the optimal policies. To evaluate the optimal policies, we outline their structures and the system performance for different configurations. An interesting result happens when the lower priority service becomes profitable. In this case, the performance of higher priority calls, which have the right to preempt, may be degraded. This is against the well known traffic engineering, which is solely concentrated on the resource guarantee characteristic of the preemptive priority that always improves the higher priority call performance by lowering its blocking probability.