A Policy-Based Framework for Automated Service Level Agreement Negotiation

Service Level Agreements (SLAs) play an important role in service-based systems. However, traditional approaches to establish SLAs are mostly manual and predefined which is not suitable for the highly dynamic and unpredictable service-oriented environment. In this paper, we propose a policy-based framework for supporting dynamic and automated SLA negotiations for Web services. In our framework, we extend the WS-Policy framework to provide a domain-independent policy language for specifying QoS constraints over the QoS attributes that are to be negotiated. Negotiation agents are dynamically created to perform SLA negotiations on behalf of each negotiating party in a P2P way using standard web services invocations. Decision making models of negotiation agents are also defined in a declarative way and can be reconfigured easily. We have implemented a prototype of our framework and demonstrated our approach through a case study.