Focuses on the argument that performance modelling and simulation has become a central issue in computer science and engineering, in part due to its applications to the structures comprising the internet. Dealing primarily with theory, tools, and techniques related to communications systems, it provides tutorials and surveys and relates new important research results. Each chapter provides background information, describes and analyses important work done in the field, and provides important direction to the reader on future work and further readings. The topics covered include traffic models for ATM networks, simulation environments, analytical methods, interprocessor communications and an evaluation of process architectures.