Estelle is a Formal Description Technique, defined within ISO (International Organization for Standardization) for specification of distributed, concurrent information processing systems. In particular, Estelle can be used to describe the services and protocols of the layers of Open Systems Interconnection (OSI) architecture defined by ISO. Its present ISO status is Draft International Standard (DIS 9074). The article outlines syntactic and semantic aspects of this description technique.

An introduction to Estelle: a specification language for distributed systems

A survey of communication protocol testing

In developing distributed systems, current trends are towards creating open distributed environments supporting interworking, interoperability, and portability, in spite of heterogeneity and autonomy of related systems. Several reference models, architectures and frameworks such as ODP, CORBA, and TINA, have already been designed and proposed. However, even though models, architectures, and frameworks, provide a good basis for developing working open distributed applications, conformance testing approaches are required for gaining confidence in final products and guaranteeing their integration and interoperability within open distributed environment. ODP provides some preliminary statements on conformance assessment in open distributed systems, but considerable work needs to be done before reaching a workable and accepted conformance testing methodology for open distributed processing. Further, ISO, ITU, OMG, and TINA-C, have recently recognized the urgent need for conformance testing. In this paper, we examine ideas gained from our experience with protocol testing, which may contribute to the design of such a framework. Our methodology is essentially guided by two features that have a great influence on all aspects of the testing process: controllability and observability.

Controllability and observability in distributed testing

Experience with RT-LOTOS, a temporal extension of the LOTOS formal description technique

On Generative Parallel Composition

With the emergence of new models, architectures and middleware such as ODP, TINA and CORBA, for developing open distributed systems, testing technology requires adaptation for use within conformance assessment in such systems. All these frameworks are object-based and aim at creating open distributed environments supporting interworking, interoperability, and portability, in spite of heterogeneity and autonomy of the related systems. In this context, an open distributed system may be viewed as a system providing standardized distributed interfaces for interacting with other systems. Conformance of such a system can be assessed by attaching a related tester at each provided interface. However, many problems of controllability and observability influencing fault detection during the testing process, arise if there is no coordination between the testers. In this paper, we show how to cope with these problems by using test coordination procedures in a distributed testing architecture.

Coordination Algorithm for Distributed Testing

From Conformance Testing to Interoperability Testing

On improving reduced reachability analysis

With emergence of new models, architectures and midlleware such as ODP, TINA and CORBA for developing open distributed systems, testing technology requires adaptation for use within conformance assessment in such systems. All these frameworks are object-based and aim at creating open distributed environments supporting interworking, interoperability, and portability, in spite of heterogeneity and autonomy of the related systems. In this context an open distributed system may be viewed as a system providing standardized distributed interfaces for interacting with other systems. Conformance of such a system can be assessed by attaching a related tester at each provided interface. However, many problems of controllability and observability influencing fault detection during the testing process arise if there is no coordination between the testers. In this paper, we show how to cope with these problems by using a distributed test method derived from OSI conformance testing. Afterwards, a CORBA prototype is designed, realized and experimented with a forum application.

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Omar Rafiq

Papers

Controllability and observability in distributed testing

Coordination Algorithm for Distributed Testing

From Conformance Testing to Interoperability Testing

On improving reduced reachability analysis

Principles and Tools for Testing Open Distributed Systems