This text is intended as a comprehensive guide to the design and analysis of computer communications protocols. It introduces a sound discipline for the design of complete and consistent protocol systems, independent of where they are used. This volume discusses the fundamental problems of designing logically consistent methods of communication between multiple computer processes. Standard protocol design problems, such as error control and flow control, are covered in detail, but also structured design methods and the construction of formal validation models. The book contains complete listings and explanations of new protocol validation and design tool called SPIN. Author is in charge of protocol design at Bell Labs. Professionals who bought Tanenbaum's COMPUTER NETWORKS, 2/E and Comer's TCP/IP will buy this. This is the first book to cover automated protocol design and validation tools extensively. Read more... Part I: Basics. 1. Introduction -- 2. Protocol Structure -- 3. Error Control -- 4. Flow Control --- Part II: Specification and Modeling. 5. Validation Models -- 6. Correctness Requirements -- 7. Protocol Design -- 8. Finite State Machines --- Part III: Conformance Testing, Synthesis and Validation. 9. Conformance Testing -- 10. Protocol Synthesis -- 11. Protocol Validation --- Part IV: Design Tools. 12. A Protocol Simulator -- 13. A Protocol Validator -- 14. Using the Validator