Alternating bit protocol

Abstract: An isomorphism between the behavior of Petri nets with exponentially distributed transition rates and Markov processes is presented. In particular, k-bounded Petri nets are isomorphic to finite Markov processes and can be solved by standard techniques if k is not too large. As a practical example, we solve for the steady state average message delay and throughput on a communication link when the alternating bit protocol is used for error recovery.

Abstract: The verification of a particular class of infinite-state systems, namely, systems consisting of finite-state processes that communicate via unbounded lossy FIFO channels, is considered. This class is able to model, e.g., link protocols such as the Alternating Bit Protocol and HDLC. For this class of systems, it is shown that several interesting verification problems are decidable by giving algorithms for verifying: the reachability problem (whether a finite set of global states is reachable from some other global state of the system); the safety property over traces, formulated as regular sets of allowed finite traces; and eventuality properties (whether all computations of a system eventually reach a given set of states). The algorithms are used to verify some idealized sliding-window protocols with reasonable time and space resources. >

Abstract: Series Foreword. Foreword. Preface. Glossary. 1. Introduction. Process Algebra. Temporal Logic. Verification. Contributions. Outline. 2. Related Work. Process Algebra. Modal Logic. Performance Analysis and Verification. 3. The Calculus. Preliminaries. CCS - the Base Calculus. PCCS - the Probabilistic Calculus. TCCS - the Timed Calculus. TPCCS - the Timed Probabilistic Calculus. Strong Bisimulation. Convenient Notation. Axiomatisation. Finite Variability of TPCCS Processes. Derived Operators. Extending TPCCS with New Operators. 4. The Logic. TPCTL Syntax. TPCTL Semantics. Relation between TPCCS and TPCTL. Properties Expressible in TPCTL. 5. Verification. The Model Checking Algorithm. Labelling Transitions with Next Formulas. Labelling Transitions with Until Formulas. Model Checking - an Example. Verifying Average Behaviours. 6. The Tool. Introduction. Syntax of Processes and Formulas. Verification. An Example. Distribution of TPWB. 7. Applications. A Vending Machine. A Train Gate. The Alternating Bit Protocol. A CSMA/CD Protocol. An Interrupt Handler. A Watchdog Timer. A Fault Tolerant System. A Process Control System. An RS232 Software Repeater,Prometheus Overtaking. Call Establishment in a Telephone Network. Call Clearing in a Telephone Network. Applications Summary and Discussion. 8. Summary and Discussion. Summary. Discussion and Directions for Future Research. The Crucial Question. A. Proofs from Chapter 3. Properties of Regular TPCCS Processes. Bisimulation Equivalence is a Congruence. The TPCCS Axiomatisation is Sound. Normal Form. Completeness of the TPCCS Axiomatisation. Ryyft/Pyyff Implies Congruence. B. Proofs from Chapters 4 and 5. Characterisation. Minimal Satisfaction. Infinite Satisfaction. Minimal Infinite Satisfaction. C. Algorithms. Identifying S30. Identifying SVO. Identifying S3 1. Identifying SV 1. D. The Timing and Probability Workbench Reference Manual. Syntax of Processes and Formulas. Commands. Macro Definitions. Bibliography. Index.

Abstract: A finite state model for the specification and validation of communication protocols is considered. The concept of “direct coupling” between interactiing finite state components is used to describe a hierarchical structure of protocol layers. The paper discusses different aspects of protocol validation, some verification tools based on the finite state formalism, and the basic limitations of the finite state modelling of protocols. An “empty medium abstraction” is proposed for reducing the complexity of the overall system description. The concept of “adjoint states” can be useful for summarizing the relative synchronization between the communicating system components. These concepts are applied to the analysis of a simple alternating bit protocol, and to the X.25 call set-up and clearing procedures. The analysis of X.25 shows that the procedures are stable in respect to intermittant perturbations in the synchronization of the interface introduced for different reasons, including occasional packet loss. However, on very rare occasions, an undesirable cyclic behaviour could be encountered.