Dynamic Re-Negotiations of SLA in Service Composition Scenarios

In a SOA environment services are implemented on top of resources across different administrative domains, in which IT infrastructure and internal resources are managed according to autonomous policies. Service Providers and their customers negotiate utility based Service Level Agreements (SLA) to determine costs and penalties based on the achieved performance levels. In B2B scenarios where several service providers are involved in the composition of a service, and each of them plays both the parts of provider and customer, several one-to-one SLAs need to be signed. In such a rigid context the global QoS of the final service can be strongly affected by any violation on each single SLA.