Abstract
This paper investigates the efficiency of a network simulator in simulating ATM networks with UBR service and compares it to the the efficiency of simulating conventional packet networks. A network simulator can be highly inefficient for cell-level ATM simulations as compared to analogous packet network simulations. We motivate and describe three techniques for improving the efficiency of ATM simulations. These techniques afford an increase in efficiency of 29-34% for ATM simulations on the x-sim network simulator.