SLA Validation of Service Value Chains

Business-to-Business (B2B) workflow/service interoperation across Virtual Organisations (VOs) brings about novel business scenarios. In these scenarios, parts of workflows (or services) corresponding to different partners can be aggregated in a producer-consumer manner, leading to hierarchical structures of added value interpreted as service value chains. Service Level Agreements (SLAs), which are contracts between service providers and service consumers, guarantee the expected quality of service (QoS) to different stakeholders at various levels of a service value chain. The essential requirements for such an SLA-based choreography of services include agile component-based infrastructure to support the corresponding choreography of their SLAs; proactive validation of SLAs to prevent violations; reactive validation of SLAs for penalty enforcement and breach management; and business enabling requirements such as trust, privacy, security and automation. In this paper we highlight the significance of these issues and propose their solutions. We then proceed to weave these solution components together into a comprehensive SLA validation framework that blends together two major systems: a rule based distributed system for SLA validation and a service monitoring system for the prevention of SLA violations.