Summary
The sliding-window protocol is specified using the notation of communicating Sequential Processes and its partial correctness is proved using the trace semantics. First the stop-and-wait protocol is defined; its correctness, that it forms a 1-place buffer, is almost evident. Next the alternating-bit protocol is defined and described in terms of the stop-and-wait protocol, and its correctness deduced from that of the stop-and-wait protocol. Finally the sliding-window protocol is described in terms of the alternating-bit protocol and its correctness deduced accordingly. The paper has two thrusts: that modularity of a specification helps to structure proofs about it (in this case, proofs that the protocols implement buffers); and that refinement in CSP leads to structured, correct implementations in occam. In support of the latter point the appendix contains a refinement and implementation of the protocols in occam 2.
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References
Chandy KM, Misra J: Parallel program design: a foundation Addison-Wesley, 1988
Duke R, Hayes I, Rose G: Verification of a cyclic retransmission protocol (preprint) University of Queensland, 1987
Hayes I: Specification case studies. Prentice Hall, 1987
Hoare CAR: Communicating sequential processes. Prentice-Hall, 1985.
inmos Ltd.: occam 2 reference manual. Prentice-Hall, 1988
International Organisation for Standardisation: Estelle: a formal description technique based on an extended state transition model. 2nd draft, proposed standard 9074, 1986
Jones G, Goldsmith MD: Programming in occam 2. Prentice Hall, 1988
Larsen, KG, Milner R: A complete protocol verification using relativized bisimulation. LFCS Rep. Ser. ECS-LFCS-86-13, 1986
Lin F, Chu P, Liu M: Protocol verification using reachability analysis: the state-space explosion problem and relief strategies. Proc ACM SIGCOMM'87 Workshop, ACM, pp 126–135, 1987
Milner R: Communication and concurrency. Prentice-Hall, 1989.
Schneider S: Communication in timed distributed computing. MSc thesis, Oxford University, 1988
Tanenbaum AS: Computer networks, 2nd edn. Prentice-Hall, 1987.
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Karen Paliwoda (now Seidel) received a degree in Mathematics (BSc) from Bradford University in 1986. She worked for two years as a research assistant at Oxford and University College, London, investigating both formal and applied aspects of communication protocols. She is currently working towards a PhD on a probabilistic model of CSP.
Jeff Sanders holds degrees in Pure Mathematics from Monash University (BSc (Hons)) and the Australian National University (PhD). He is a University Lecturer at Oxford and a Tutorial Fellow at Lady Margaret Hall, with interests in the mathematics of Computation.
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Paliwoda, K., Sanders, J.W. An incremental specification of the sliding-window protocol. Distrib Comput 5, 83–94 (1991). https://doi.org/10.1007/BF02259750
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DOI: https://doi.org/10.1007/BF02259750