For the simulation of stochastic systems, techniques that can speed up the simulation are essential, as they increase the accuracy that can be achieved within a given run-time, particularly with a focus on rare events. Eugen Lamers explains the principle of simulation speed-up in general, demonstrates the technique RESTART for the simulation of rare events, and addresses its efficiency on distributed systems. Due to the nature of RESTART, the efficiency is limited by high communication overhead. The author introduces the Short-Term Dynamic Simulation concept, developed for the planning of mobile radio networks, which enables fast state space coverage while considering dynamic aspects. He analyzes the speed-up potential on a theoretical basis using analytically solvable Markov models for different utilizations, along with realistic models for UMT.