Pierre Combes

Modeling and verification of a telecommunication application using live sequence charts and the play-engine tool

We apply the language of live sequence charts (LSCs) and the Play-Engine tool to a real-world complex telecommunication service. The service, called Depannage, allows a user to make a phone call and ask for help from a doctor, the fire brigade, a car maintenance service, etc. This kind of service is built on top of an embedded platform, using both new and existing service components. The complexity of such applications stems from their distributed architecture, the various time constraints they entail, and the fact the underlying systems are rapidly evolving, introducing new components, protocols and associated hardware constraints, all of which must be taken into account. We present the results of our work on the specification, animation and formal verification of the Depannage service, and draw some initial conclusions as to an appropriate methodology for using a scenario-based approach in the telecommunication domain. The complete specification of the Depannage application in LSCs and some animations showing simulation and verification results are made available as supplementary material.

Service validation

Ž . This paper gives an overview on validation methods and techniques for service creation in an Intelligent Network IN . A description of different components of Service Creation Environment is provided, focusing on the validation tasks to perform in order to fulfil the requirements of all the actors involved in the service life cycle. Then, we describe how SDL and MSC methods and tools can be used efficiently in service specification and requirement validation. Finally, we emphasize on service interaction detection performed by checking that the requirements of existing services are still satisfied when other services are introduced. q 1999 Published by Elsevier Science B.V. All rights reserved.

An open animation tool: application to telecommunication systems

This paper presents an animation environment based on an open and flexible architecture. Its flexible architecture allows animating different animation sources (formal and executable language like SDL or scenario languages like MSC or UML sequence diagrams). The animation multimedia user interface allows integrating different multimedia objects and different types of representations.This animation environment has been intensively used for telecommunication applications at different levels of a service and network architecture: service animation from the users point of view or from the service logic point of view (service logic and service feature logics), protocols and application programming interface (such as OSA/PARLAY) animation, service interaction analysis. Animation helps obtaining a comprehensive and user-friendly interface for education, and investigation of system behaviour from different points of view, in particular from a client point of view. Specifically applied to formal executable models (using SDL, for example), the tool helps checking properties of the system behaviour, and showing whether it really fulfils user expectations.

A language for quality of service requirements specification in web services orchestrations

Service Oriented Architecture industry aims to deliver agile service infrastructures. In this context, solutions to specify service compositions (mostly BPEL language) and Quality of Service (QoS) of individual services have emerged. However, architects still lack adapted means to specify and implement QoS in service compositions. Typically, they use ad-hoc technical solutions that significantly reduce flexibility and require cost-effective development. Our approach aims to overcome this shortcoming by introducing both a new language and tool for QoS Specification and implementation in service compositions. More specifically, our language is a declarative domain-specific language that allows the architect to specify QoS constraints and mechanisms in Web Service orchestrations. Our tool is responsible for the QoS constraints processing and for QoS mechanisms injection into the orchestration. A key property of our approach is to preserve compatibility with existing languages and standards. In this paper, we present our language and tool, as well as an illustrative scenario dealing with multiple QoS concerns.

A Multi-service and Multi-protocol Validation Platform – Experimentation Results

This article presents the implementation of a validation platform based on formal methods and the experimental results obtained. This platform allows performing conformance and interoperability tests, analysing the specification and constructing a performance model for the services. It covers all stages of the validation which are: formal specification, test architecture definition, test generation and execution for the defined architecture, and performance evaluation. The test methods and architectures used here make it easier to detect and localise errors. The platform has been constructed within the framework of the RNRT (National Telecommunications Research Network) platform project, PLATONIS. This platform is composed of a network integrating the different sites of the project partners. The principal application domains for the platform are telecommunication systems and mobile telephony. In particular, two different cases study are presented that illustrate the platform’s applicability to the test of mobile 3rd generation protocols and services using WAP, GPRS and UMTS. Nevertheless, the platform is generic and can be used for other types of communication protocols and services.

Looking for better integration of design and performance engineering

In various domains, performance evaluation has proved very valuable, especially when done at early stages of the development process; the simulation technique, in particular, combines good properties (flexibility, low-cost, relevance of results) for the prediction of software systems performance. However, too often performance engineering is kept separate from the design process of software systems. We try to analyze reasons for that, and discuss ways to better motivate designers to tackle performance evaluation. We then present an approach that aims at producing performance models from design-oriented specifications (based on scenario and/or automata formalisms, such as MSC/SDL). The approach is well adapted to the study of service platforms, and targets basic queuing networks that offer a flexible and powerful framework for modeling performance, as well as mature simulators on the market.

IN Service Prototyping using SDL Models and Animation

This paper describes a environment for service prototyping based on the graphical animation of the service logic. It is based on SDL models of services and network. It aims at simulating and animating the service behaviour from different actors points of view, mainly from the user and subscriber points of view. Applied at different steps of service creation, from the elaboration of the first idea of a new service to the validation of the service logic design, taking into account architectural constraints, this simulation and animation environment helps to guarantee the validation of service requirements between service provider, service developer, subscriber and users. The environment presented here allows the validation of different service domains: call processing but also management scripts.

Une plate-forme de validation multi-protocoles et multi-services Résultats d’expérimentation

RésuméCet article présente la mise en œuvre et les résultats d’expérimentation d’une plate-forme de validation basée sur des méthodes formelles. Cette plate-forme permet de réaliser des tests de conformité et d’interopérabilité, d’analyser la QdS (Qualité de Service) et de produire un modèle de performance pour les services. Elle couvre toutes les étapes de validation: spécification formelle, définition des architectures de test, génération et exécution des tests sur une architecture donnée, et l’évaluation des performances. Les méthodes de test et les architectures présentées facilitent la détection et la localisation des erreurs.La plate-forme a été réalisée dans le cadre d’un projet plate-forme duRnrt (Réseau National de Recherche en Télécommunications),Platonis. Cette plate-forme possède une configuration réseau au niveau national avec des sites dans les laboratoires partenaires du projet.Les systèmes de télécommunications et la téléphonie mobile sont les domaines principaux d’application de la plate-forme. En particulier, deux études de cas sont présentées, celles-ci illustrent son application au test des protocoles et des services pour les réseaux cellulaires de 3e génération (utilisant leWap, gprs etUts). Mais il s’agit d’une plateforme générique qui pourra être utilisée pour d’autres types de services et protocoles de communication.AbstractThis article presents the implementation of a validation platform based on formal methods and the experimental results obtained. This platform allows performing conformance and interoperability tests, analysing the specification and constructing a performance model for the services. It covers all stages of the validation which are: formal specification, test architecture definition, test generation and execution for the defined architecture, and performance evaluation. The test methods and architectures used here make it easier to detect and localise errors. The platform has been constructed within the framework of theRnrt (National Telecommunications Research Network) platform project, platonis. This platform is composed of a network integrating the different sites of the project partners. The principal application domains for the platform are telecommunication systems and mobile telephony. In particular, two different cases study are presented that illustrate the platform’s applicability to the test of mobile 3rd generation protocols and services usingWap, gprs andUmts. Nevertheless, the platform is generic and can be used for other types of communication protocols and services.