Abstract no. 555: Extending WS-Agreement To Support Grid Service Level Agreements Renegotiation Sanaa Sharaf, Karim Djemame School of Computing, University of Leed Grid Computing allows users to share resources in both commercial and scientific environments. This dependency on Grid systems accelerated the need for replacing the ―best-effort‖ approach used in most Grid environments with a more controlled and reliable one to achieve the high levels of Quality of Service (QoS) necessary to potential users. Service Level Agreements (SLAs) are electronic contracts between the service provider and service consumer, which provide a formal method for describing QoS requirements, guarantee terms and the responsibilities of each party. The WS-Agreement is a Web Service protocol used to establish an agreement between service providers and service consumers; the definition of the protocol is very general and does not contemplate the possibility of changing an agreement at runtime. The occurring of an unexpected event at runtime may be an important reason for reducing the reliability and trustworthiness of parties. The challenge is to make agreements robust and more long-lived to individual term violations. This research shows extensions of the WS-Agreement specification to support the dynamic nature of SLAs by allowing the possibility of SLA renegotiation at run time.
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