Service-level enforcement in web-services-based systems

Abstract

Web-services-based systems present challenges for service-level enforcement. Contrary to typical enterprise architectures where we are in control of all services and can easily specify and monitor service levels, here we need self-adapting approaches. This article proposes an approach for the assurance of service levels. The steps of the approach are: the formalisation of requirements using a Service Level Objective (SLO), the formalisation of web service properties in a service-level capability statement and adaptive actions based on the translucent replication of services. The evaluation is based on a reference process model in Business Processing Modelling Notation (BPMN) and subsequent mapping at the infrastructure level. This mapping includes the definition, implementation and deployment of web services that cover the functional requirements, orchestration and coordination of these services using Business Process Execution Language (BPEL), as well as the the runtime monitoring and assurance of Nonfunctional Properties (NFPs) within a business process management framework.