RESTART: a straightforward method for fast simulation of rare events

This paper presents a method for fast simulation of rare events, called RESTART (REpetitive Simulation Trials After Reaching Thresholds). The method obtains dramatic computer time savings for an equal confidence of the results. The paper describes the method in its multiple thresholds version, shows the efficiency of the method and gives criteria to choose its parameters. It presents a simulation library (ASTRO) in which RESTART is implemented and, finally, application examples to teletraffic and reliability problems are provided.