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27
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 (35 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 the v ..."
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Cited by 83 (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 71 (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 ...
Symbolic Verification of Lossy Channel Systems: Application to the Bounded Retransmission Protocol
 In TACAS'99. LNCS 1579
, 1999
"... We consider the problem of verifying automatically infinitestate systems that are systems of finite machines that communicate by exchanging messages through unbounded lossy fifo channels. In a previous work [1], we proposed an algorithmic approach based on constructing a symbolic representation ..."
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Cited by 36 (5 self)
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We consider the problem of verifying automatically infinitestate systems that are systems of finite machines that communicate by exchanging messages through unbounded lossy fifo channels. In a previous work [1], we proposed an algorithmic approach based on constructing a symbolic representation of the set of reachable configurations of a system by means of a class of regular expressions (SREs). The construction of such a representation consists of an iterative computation with an acceleration technique which enhance the chance of convergence. This technique is based on the analysis of the effect of iterating control loops. In the work we present here, we experiment our approach and show how it can be effectively applied. For that, we developed a tool prototype based on the results in [1]. Using this tool, we provide a fully automatic verification of (the parameterized version of) the Bounded Retransmission Protocol, for arbitrary values of the size of the transmitted files, and the allowed number of retransmissions. ? Contact author. 1 1
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...
Regular Model Checking Using Inference of Regular Languages
, 2004
"... Regular model checking is a method for verifying infinitestate systems based on coding their configurations as words over a finite alphabet, sets of configurations as finite automata, and transitions as finite transducers. We introduce a new general approach to regular model checking based on infer ..."
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Cited by 29 (2 self)
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Regular model checking is a method for verifying infinitestate systems based on coding their configurations as words over a finite alphabet, sets of configurations as finite automata, and transitions as finite transducers. We introduce a new general approach to regular model checking based on inference of regular languages. The method builds upon the observation that for infinitestate systems whose behaviour can be modelled using lengthpreserving transducers, there is a finite computation for obtaining all reachable configurations up to a certain length n. These configurations are a (positive) sample of the reachable configurations of the given system, whereas all other words up to length n are a negative sample. Then, methods of inference of regular languages can be used to generalize the sample to the full reachability set (or an overapproximation of it). We have implemented our method in a prototype tool which shows that our approach is competitive on a number of concrete examples. Furthermore, in contrast to all other existing regular model checking methods, termination is guaranteed in general for all systems with regular sets of reachable configurations. The method can be applied in a similar way to dealing with reachability relations instead of reachability sets too.
Verification of Communication Protocols Using Data Flow Analysis
 IN PROCEEDINGS OF THE FOURTH ACM SIGSOFT SYMPOSIUM ON THE FOUNDATIONS OF SOFTWARE ENGINEERING
, 1996
"... In this paper we demonstrate that data flow analysis is an effective approach for verifying requirements of communication protocols. Communication protocols are responsible for establishing the communication patterns between different processes within a distributed computer system. Data flow analy ..."
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Cited by 23 (6 self)
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In this paper we demonstrate that data flow analysis is an effective approach for verifying requirements of communication protocols. Communication protocols are responsible for establishing the communication patterns between different processes within a distributed computer system. Data flow analysis is a static analysis method for increasing confidence in the correctness of software systems by automatically verifying that a given software artifact (e.g., design or code) must behave consistently with a specified requirement. In this case study, we apply the FLAVERS data flow analysis tool to pseudocode designs of the three way handshake connection establishment protocol and of the alternating bit protocol and prove that the behavior of the pseudocode is consistent with protocol behavioral requirement specifications. In addition, we show how assumptions about the environment in which a software system is executed can be incorporated into the analysis, using message losses as an...
Generalized Fair Reachability Analysis for Cyclic Protocols with Nondeterminism and Internal Transitions
 In IEEE/ACM Transactions on Networking
, 1996
"... In this paper, we extend the generalized fair reachability notion to cyclic protocols with nondeterminism and internal transitions. By properly incorporating internal transitions into the formulation of fair progress vectors, we prove that most of the results established for cyclic protocols without ..."
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Cited by 16 (1 self)
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In this paper, we extend the generalized fair reachability notion to cyclic protocols with nondeterminism and internal transitions. By properly incorporating internal transitions into the formulation of fair progress vectors, we prove that most of the results established for cyclic protocols without nondeterminism and internal transitions still hold even if nondeterminism and internal transitions are allowed. We identify indefiniteness as a new type of logical error resulting from reachable internal execution cycles and show that indefiniteness can also be detected for the class of cyclic protocols with finite fair reachable state spaces with finite extensions. 1 Introduction It is wellknown that state explosion is one of the major obstacles for validating complex protocols modeled as communicating finite state machines. As a result, many techniques have been proposed to tackle this problem (please refer to [10] for a survey). It is observed that in most cases, significant state red...
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]