Techniques for measuring and modeling ATM traffic are reviewed. The requirements for cell level ATM network modeling and simulation are then outlined followed by a description of an ATM traffic and network (ATM-TN) simulator. This ATM-TN simulator is built upon parallel simulation mechanisms to achieve the high performance needed to execute the huge number of cell events required for a realistic network scenario. Results for several simulation experiments are reported using this high performance simulation including scenarios for the Wnet and OPERA networks. Finally, a preliminary evaluation of the application of high performance simulation to the design and analysis of ATM network performance is provided.