Testing of Communicating Systems presents the latest international results in both the theory and industrial practice of the testing of communicating systems. The topics discussed range from tools and techniques for testing to test standards, frameworks, notations, algorithms, fundamentals of testing, and industrial experiences and issues. The tools and techniques discussed apply to conformance testing, interoperability testing, performance testing of communications software, Internet prools and applications, and multimedia and distributed systems in general, such as systems for electronic commerce. This volume contains the extensively refereed proceedings of the 13th International Conference on Testing of Communicating Systems (TestCom 2000), which was sponsored by the International Federation for Information Processing (IFIP) and held in Ottawa, Ontario, Canada in early September 2000. Testing of Communicating Systems is essential reading for engineers, designers, managers of IT products and services, and all researchers interested in advancing the technology of engineering Internet frameworks, systems, services, and applications for reliability and quality.