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Verifying Programs with Unreliable Channels (Extended Abstract)
 Information and Computation
, 1992
"... The research on algorithmic verification methods for concurrent and parallel systems has mostly focussed on finitestate systems, with applications in e.g. communication protocols and hardware systems. For infinitestate systems, e.g. systems that operate on data from unbounded domains, algorithmic ..."
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Cited by 176 (36 self)
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The research on algorithmic verification methods for concurrent and parallel systems has mostly focussed on finitestate systems, with applications in e.g. communication protocols and hardware systems. For infinitestate systems, e.g. systems that operate on data from unbounded domains, algorithmic verification is more difficult, since most verification problems are in general undecidable. In this paper, we consider the verification of a particular class of infinitestate systems, namely systems consisting of finitestate processes that communicate via unbounded lossy FIFO channels. This class is able to model e.g. link protocols such as the Alternating Bit Protocol and HDLC. The unboundedness of the channels makes these systems infinitestate. For this class of systems, we show that several interesting verification problems are decidable by giving algorithms for verifying the following classes of properties.
Symbolic Verification of Communication Protocols with Infinite State Spaces using QDDs (Extended Abstract)
 In CAV'96. LNCS 1102
"... ) Bernard Boigelot Universit'e de Li`ege Institut Montefiore, B28 4000 Li`ege SartTilman, Belgium Email: boigelot@montefiore.ulg.ac.be Patrice Godefroid Lucent Technologies  Bell Laboratories 1000 E. Warrenville Road Naperville, IL 60566, U.S.A. Email: god@belllabs.com Abstract We study ..."
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Cited by 82 (7 self)
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) Bernard Boigelot Universit'e de Li`ege Institut Montefiore, B28 4000 Li`ege SartTilman, Belgium Email: boigelot@montefiore.ulg.ac.be Patrice Godefroid Lucent Technologies  Bell Laboratories 1000 E. Warrenville Road Naperville, IL 60566, U.S.A. Email: god@belllabs.com Abstract We study the verification of properties of communication protocols modeled by a finite set of finitestate machines that communicate by exchanging messages via unbounded FIFO queues. It is wellknown that most interesting verification problems, such as deadlock detection, are undecidable for this class of systems. However, in practice, these verification problems may very well turn out to be decidable for a subclass containing most "real" protocols. Motivated by this optimistic (and, we claim, realistic) observation, we present an algorithm that may construct a finite and exact representation of the state space of a communication protocol, even if this state space is infinite. Our algorithm performs a loo...
OntheFly Analysis of Systems with Unbounded, Lossy FIFO Channels
 In CAV'98. LNCS 1427
, 1998
"... . We consider symbolic onthefly verification methods for systems of finitestate machines that communicate by exchanging messages via unbounded and lossy FIFO queues. We propose a novel representation formalism, called simple regular expressions (SREs), for representing sets of states of proto ..."
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Cited by 72 (17 self)
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. We consider symbolic onthefly verification methods for systems of finitestate machines that communicate by exchanging messages via unbounded and lossy FIFO queues. We propose a novel representation formalism, called simple regular expressions (SREs), for representing sets of states of protocols with lossy FIFO channels. We show that the class of languages representable by SREs is exactly the class of downward closed languages that arise in the analysis of such protocols. We give methods for (i) computing inclusion between SREs, (ii) an SRE representing the set of states reachable by executing a single transition in a system, and (iii) an SRE representing the set of states reachable by an arbitrary number of executions of a control loop of a program. All these operations are rather simple and can be carried out in polynomial time. With these techniques, one can construct a semialgorithm which explores the set of reachable states of a protocol, in order to check variou...
Undecidable Verification Problems for Programs with Unreliable Channels
 Information and Computation
, 1994
"... We consider the verification of a particular class of infinitestate systems, namely systems consisting of finitestate processes that communicate via unbounded lossy FIFO channels. This class is able to model e.g. link protocols such as the Alternating Bit Protocol and HDLC. In an earlier paper, we ..."
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Cited by 58 (11 self)
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We consider the verification of a particular class of infinitestate systems, namely systems consisting of finitestate processes that communicate via unbounded lossy FIFO channels. This class is able to model e.g. link protocols such as the Alternating Bit Protocol and HDLC. In an earlier paper, we showed that the problems of checking reachability, safety properties, and eventuality properties are decidable for this class of systems. In this paper, we show that the following problems are undecidable, namely ffl The model checking problem in propositional temporal logics such as Propositional Linear Time Temporal Logic (PTL) and Computation Tree Logic (CTL). ffl The problem of deciding eventuality properties with fair channels: do all computations eventually reach a given set of states if the unreliable channels satisfy fairness assumptions. The results are obtained through a reduction from a variant of Post's Correspondence Problem. This research report is a revised and extended ...
Using Forward Reachability Analysis for Verification of Lossy Channel Systems
 Formal Methods in System Design
, 2004
"... We consider symbolic onthefly verification methods for systems of finitestate machines that communicate by exchanging messages via unbounded and lossy FIFO queues. We propose a novel representation formalism, called simple regular expressions (SREs), for representing sets of states of protoco ..."
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Cited by 30 (4 self)
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We consider symbolic onthefly verification methods for systems of finitestate machines that communicate by exchanging messages via unbounded and lossy FIFO queues. We propose a novel representation formalism, called simple regular expressions (SREs), for representing sets of states of protocols with lossy FIFO channels. We show that the class of languages representable by SREs is exactly the class of downward closed languages that arise in the analysis of such protocols. We give methods for (i) computing inclusion between SREs, (ii) an SRE representing the set of states reachable by executing a single transition in a system, and (iii) an SRE representing the set of states reachable by an arbitrary number of executions of a control loop of a program. All these operations are rather simple and can be carried out in polynomial time. With these techniques, one can straightforwardly construct an algorithm which explores the set of reachable states of a protocol, in order t...
Probabilistic Lossy Channel Systems
, 1996
"... Consider a system of finite state machines communicating with each other over unbounded FIFO buffers. Such a model of computation is, clearly, turing powerful. This model has been used as the backbone of ISO protocol specification languages Estelle and SDL, as it allows one to abstract away from ..."
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Cited by 25 (2 self)
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Consider a system of finite state machines communicating with each other over unbounded FIFO buffers. Such a model of computation is, clearly, turing powerful. This model has been used as the backbone of ISO protocol specification languages Estelle and SDL, as it allows one to abstract away from the details, such as errors in communication, that occur at lower levels of the protocol stack. It has recently been shown (in the literature) that realistic models which implicitly model errors in the communication buffers are more tractable than models which assume perfect communication. In this paper, we propose to make the model more realistic by modeling the probability of loss in the buffers. Given specifications in such a model we provide algorithms for the probabilistic reachability problem and the probabilistic modelchecking (against lineartime PTL requirements) problem.
WellAbstracted Transition Systems: Application to FIFO Automata
, 2000
"... this paper on symbolic representations for the computation of the reachability set of FIFO automata  a finite control with multiple unbounded FIFO channels. To the best of our knowledge, Pachl uses for the first time regular expressions to represent infinite sets of channel contents [31]. In [17] ..."
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Cited by 16 (6 self)
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this paper on symbolic representations for the computation of the reachability set of FIFO automata  a finite control with multiple unbounded FIFO channels. To the best of our knowledge, Pachl uses for the first time regular expressions to represent infinite sets of channel contents [31]. In [17], linear regular expressions have been defined and used. Boigelot et al. chosed a deterministic finite automata based representation, namely Queuecontent Decision Diagrams [4] and afterwards Bouajjani et al. added Pressburger formulas, namely Constrained QDDs [5]. Simple regular expressions have been introduced for lossy FIFO automata [1]
Integer Linear Programming Based Property Checking for Asynchronous Reactive Systems
 IEEE TRANSACTIONS ON SOFTWARE ENGINEERING
, 2010
"... Asynchronous reactive systems form the basis of a wide range of software systems, for instance in the telecommunications domain. It is highly desirable to rigorously show that these systems are correctly designed. However, traditional formal approaches to the verification of these systems are often ..."
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Cited by 1 (0 self)
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Asynchronous reactive systems form the basis of a wide range of software systems, for instance in the telecommunications domain. It is highly desirable to rigorously show that these systems are correctly designed. However, traditional formal approaches to the verification of these systems are often difficult because asynchronous reactive systems usually possess extremely large or even infinite state spaces. We propose an Integer Linear Program (ILP) solving based property checking framework that concentrates on the local analysis of the cyclic behavior of each individual component of a system. We apply our framework to the checking of the buffer boundedness and livelock freedom properties, both of which are undecidable for asynchronous reactive systems with an infinite state space. We illustrate the application of the proposed checking methods to Promela, the input language of the SPIN model checker. While the precision of our framework remains an issue, we propose a counterexample guided abstraction refinement procedure based on the discovery of dependencies among control flow cycles. We have implemented prototype tools with which we obtained promising experimental results on real life system models.
Model Checking Probabilistic Lossy Channel Systems
, 1998
"... Lossy channel systems model a set of finite state processes interacting with each other over unbounded, lossy FIFO channels. This computational model is an abstraction of protocols in the lower layers of the network protocol hierarchy. In spite of its unbounded FIFO queues the Lossy channel system m ..."
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Cited by 1 (0 self)
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Lossy channel systems model a set of finite state processes interacting with each other over unbounded, lossy FIFO channels. This computational model is an abstraction of protocols in the lower layers of the network protocol hierarchy. In spite of its unbounded FIFO queues the Lossy channel system model is not turingpowerful. It has been shown that the reachability problem is decidable [1]. However, the modelchecking problem, against specifications in linear time temporal logic (LTL), is known to be undecidable [2]. Given that the rate of message loss in communication systems can be probabilistically characterized we consider a probabilistic version of Lossy channel systems. We show that the problem of checking whether a LTL requirement holds almost always. i.e., with probability 1, of probabilistic lossy channel systems (PLCS) is decidable. As can be expected the probability of message loss does not play a part in the modelchecking procedure. 1 Introduction Finite state machines w...
Heuristic Search for Unbounded Executions
"... Abstract. We present a heuristic search based approach to finding unbounded executions in software models that can be described using Communicating Finite State Machines (CFSMs). This improves the unboundedness test devised by Jeron and Jard in case certain knowledge about potential sources of unbou ..."
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Abstract. We present a heuristic search based approach to finding unbounded executions in software models that can be described using Communicating Finite State Machines (CFSMs). This improves the unboundedness test devised by Jeron and Jard in case certain knowledge about potential sources of unboundedness is available. Such knowledge can be obtained from a boundedness analysis that we designed in precursory work. We evaluate the effectiveness of several different heuristics and search strategies. To show the feasibility of our approach, we compare the performance of the heuristic search algorithms with that of uninformed search algorithms in detecting unbounded executions for a number of case studies. We discuss the applicability of our approach to high level modeling languages for concurrent systems such as Promela. 1