An ATM simulation system with realistic traffic modeling

Asynchronous transfer mode (ATM) technology has promised to support multiple traffic types over a single network. The problem thus far has been to support different traffic types while maintaining the proper quality of service (QoS) parameters for all types of traffic. This paper describes a simulation system that allows the analysis of realistic integrated traffic patterns in ATM networks. The system is extensible to support new traffic patterns and can emulate most current ATM switch architectures. Different traffic patterns, buffering schemes, and traffic policing strategies are implemented in the simulator. Traffic streams composed of a constant bit rate stream, a variable bit rate stream and a available bit rate stream are used as inputs to the simulator to evaluate ATM network performance in terms of QoS parameters. The leaky-bucket algorithm is also used in the simulator for traffic policing and shaping. Simulation results of a variety of conditions are presented in this paper. Of particular interest is the simulation of both partial packet discard and early packet discard algorithms for efficient transmission of Internet protocol datagrams over ATM. Simulation results show that early packet discard can reduce network link utilization by up to 10% under heavy loads by eliminating traffic that is destined to be discarded by the receiving host.