Recent analysis of real network traac has shown that a large number of traac sources produces a traf-c stream that is self-similar over several time scales. Motivated by this observation a high-speed Asynchronous Transfer Mode (ATM) traac generator based on fractional Brow-nian motion is presented. The traac simulator generates call arrivals as well as the desired traac parameters for each call. It is therefore an ideal tool to analyze a wide spectrum of networking functions such as switch performance, routing , and call admission control algorithms. The presented algorithm can be highly parallelized, thus generating traac logs in a period several orders of magnitude below the actual simulated time period.