Precise Service Level Agreements

James Skene, Davide Lamanna and Wolfgang Emmerich

Dept. of Computer Science,
University College London
Dept. of Computer Science
Gower Street, London, WC1E 6BT UK

Abstract:
SLAng is an XML language for defining service level agreements, the part of a contract between the client and provider of an Internet service that describes the quality attributes that the service is required to possess. We define the semantics of SLAng precisely by modelling the syntax of the language in UML, then embedding the language model in an environmental model that describes the structure and behaviour of services. The presence of SLAng elements imposes behavioural constraints on service elements, and the precise definition of these constraints using OCL constitutes the semantic description of the language. We use the semantics to define a notion of SLA compatibility, and an extension to UML that enables the modelling of service situations as a precursor to analysis, implementation and provisioning activities.


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Updated on: 11/12/2004
Wolfgang Emmerich