5,286 research outputs found

    Hardware/Software Co-design of Communication Protocols

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    An important aspect in providing high performance distributed systems such as multimedia systems is the combined use of hardware and software in the end systems. System design techniques should allow hardware/software co-design to integrate both means of implementation. In this paper, we show how the standardized formal language Estelle can be used to facilitate co-design. The system will first be designed in Estelle. At the point in time of final decision on which parts to implement in software and which in hardware, the original specification will be split into several partial specifications. The software parts are translated into C code, while the hardware parts are translated into VHDL code for further analysis and development. We present a tool environment which supports the protocol developer in the design and implementation process. A simple Video-on-Demand example shows the usefulness of the tool environment

    Analysis and representation of test cases generated from LOTOS

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    Cataloged from PDF version of article.This paper presents a method to generate, analyse and represent test cases from protocol specification. The language of temporal ordering specification (LOTOS) is mapped into an extended finite state machine (EFSM). Test cases are generated from EFSM. The generated test cases are modelled as a dependence graph. Predicate slices are used to identify infeasible test cases that must be eliminated. Redundant assignments and predicates in all the feasible test cases are removed by reducing the test case dependence graph. The reduced test case dependence graph is adapted for a local single-layer (LS) architecture. The reduced test cases for the LS architecture are enhanced to represent the tester's behaviour. The dynamic behaviour of the test cases is represented in the form of control graphs by inverting the events, assigning verdicts to the events in the enhanced dependence graph. © 1995

    On the testability of SDL specifications

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    The problem of testing from an SDL specification is often complicated by the presence of infeasible paths. This paper introduces an approach for transforming a class of SDL specification in order to eliminate or reduce the infeasible path problem. This approach is divided into two phases in order to aid generality. First the SDL specification is rewritten to create a normal form extended finite state machine (NF-EFSM). This NF-EFSM is then expanded in order to produce a state machine in which the test criterion may be satisfied using paths that are known to be feasible. The expansion process is guaranteed to terminate. Where the expansion process may lead to an excessively large state machine, this process may be terminated early and feasible paths added. The approach is illustrated through being applied to the Initiator process of the Inres protocol

    Efficient Implementation of Estelle Specifications

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    Efficient implementation of communication software is of critical importance for high-speed networks. We analyze performance bottlenecks in existing implementations and propose two techniques for improvements: The first exploits parallelism not only in the actions of the FSMs, but also in the runtime system of the protocol stack. The second integrates adjacent layers leading to considerable savings in inter-layer interface handling and in the number of transitions occurring in the FSMs. Both techniques are discussed in the context of OSI upper layers, and are based on protocol specification in Estelle

    An integrated search-based approach for automatic testing from extended finite state machine (EFSM) models

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    This is the post-print version of the Article - Copyright @ 2011 ElsevierThe extended finite state machine (EFSM) is a modelling approach that has been used to represent a wide range of systems. When testing from an EFSM, it is normal to use a test criterion such as transition coverage. Such test criteria are often expressed in terms of transition paths (TPs) through an EFSM. Despite the popularity of EFSMs, testing from an EFSM is difficult for two main reasons: path feasibility and path input sequence generation. The path feasibility problem concerns generating paths that are feasible whereas the path input sequence generation problem is to find an input sequence that can traverse a feasible path. While search-based approaches have been used in test automation, there has been relatively little work that uses them when testing from an EFSM. In this paper, we propose an integrated search-based approach to automate testing from an EFSM. The approach has two phases, the aim of the first phase being to produce a feasible TP (FTP) while the second phase searches for an input sequence to trigger this TP. The first phase uses a Genetic Algorithm whose fitness function is a TP feasibility metric based on dataflow dependence. The second phase uses a Genetic Algorithm whose fitness function is based on a combination of a branch distance function and approach level. Experimental results using five EFSMs found the first phase to be effective in generating FTPs with a success rate of approximately 96.6%. Furthermore, the proposed input sequence generator could trigger all the generated feasible TPs (success rate = 100%). The results derived from the experiment demonstrate that the proposed approach is effective in automating testing from an EFSM

    An Estelle Compiler for Multiprocessor Platforms

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    Efficient implementation of communication software is of critical importance for high-speed networks. Parallelism can improve the runtime performance of implementations gained by code generation. Therefore, we have modified an existing Estelle compiler to run under OSF/1. It exploits parallelism not only in the actions of the FSMs, but also in the runtime system of the protocol stack

    Modeling and Testing Implementations of Protocols with Complex Messages

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    This paper presents a new language called APSL for formally describing protocols to facilitate automated testing. Many real world communication protocols exchange messages whose structures are not trivial, e.g. they may consist of multiple and nested fields, some could be optional, and some may have values that depend on other fields. To properly test implementations of such a protocol, it is not sufficient to only explore different orders of sending and receiving messages. We also need to investigate if the implementation indeed produces correctly formatted messages, and if it responds correctly when it receives different variations of every message type. APSL's main contribution is its sublanguage that is expressive enough to describe complex message formats, both text-based and binary. As an example, this paper also presents a case study where APSL is used to model and test a subset of Courier IMAP email server
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