This partial view typically does not contain long paths. This is generally desirable since using long paths would tie up more resources. It is clear from our past work that considering the interaction among various controls significantly improves performance. In order to design truly integrated dynamic QoS control for large networks in a cost-effective way, it is crucial to find efficient and accurate modeling and evaluation tools. Unfortunately, traditional tools do not seem effective.
Analytical approaches are often too coarse , ignoring detailed and dynamic situations.
Simulation approaches are often too expensive due to the need for a large number of replicated simulation runs to obtain descent confidence measures. The method is general and applicable to multi-class systems. We used it to evaluate a number of simple multi-class systems, including integrated services networks and parallel database servers. The method has proven to be both accurate and fast, providing modeling power close to that of simulation at a fraction of the computation expense. A key component of this method is to develop models for wireline and wireless links that reflect their different characteristics, QoS scheduling and admission control algorithms.