An Adaptive and Intelligent SLA Negotiation System for Web Services

The effective use of services to compose business processes in services computing demands that the Quality of Services (QoS) meet consumers´ expectations. Automated web-based negotiation of Service Level Agreements (SLA) can help define the QoS requirements of critical service-based processes. We propose a novel trusted Negotiation Broker (NB) framework that performs adaptive and intelligent bilateral bargaining of SLAs between a service provider and a service consumer based on each party´s high-level business requirements. We define mathematical models to map business-level requirements to low-level parameters of the decision function, which obscures the complexity of the system from the parties. We also define an algorithm for adapting the decision functions during an ongoing negotiation to comply with an opponent´s offers or with updated consumer preferences. The NB uses intelligent agents to conduct the negotiation locally by selecting the most appropriate time-based decision functions. The negotiation outcomes are validated by extensive experimental study for Exponential, Polynomial, and Sigmoid time-based decision functions using simulations on our prototype framework. Results are compared in terms of a total utility value of the negotiating parties to demonstrate the efficiency of our proposed approach.