Monotonicity in Service Orchestrations

Anne Bouillard1

Description

Niveau: Supérieur, Doctorat, Bac+8
Monotonicity in Service Orchestrations? Anne Bouillard1, Sidney Rosario2, Albert Benveniste2, and Stefan Haar3 1 ENS Cachan, IRISA, Universite Europeenne de Bretagne, Bruz France 2 IRISA/INRIA, Campus de Beaulieu, Rennes France 3 INRIA Saclay, ENS Cachan, France Abstract. Web Service orchestrations are compositions of different Web Services to form a new service. The services called during the orches- tration guarantee a given Quality of Service (QoS) to the orchestrator, usually in the form of contracts. These contracts can then be used by the orchestrator to deduce the contract it can offer to its own clients, by performing contract composition. An implicit monotonicity assump- tion in contract based QoS management is: “the better the component services perform, the better the orchestration's performance will be”. In some orchestrations, however, monotonicity can be violated, i.e., the performance of the orchestration improves when the performance of a component service degrades. This is highly undesirable since it can render the process of contract composition inconsistent. In this paper we formally define monotonicity for orchestrations modelled by Colored Occurrence Nets (CO-nets) and we characterize the classes of monotonic orchestrations. Contracts can be formulated as hard, possi- bly nondeterministic, guarantees, or alternatively as probabilistic guar- antees. Our work covers both cases. We show that few orchestrations are indeed monotonic, mostly because of complex interactions between control, data, and timing.

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• aspects also


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• services called


• orchestration


• service


• contracts can


• qos

Sujets

• France 2
• Orchestration
• Service

Informations

• Publié par: profil-zyak-2012
• Nombre de lectures: 9
• Langue: English

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