209 A. Adi et al. (Eds.): RuleML 2005, LNCS 3791, pp. 209–217, 2005. © Springer-Verlag Berlin Heidelberg 2005 ContractLog: An Approach to Rule Based Monitoring and Execution of Service Level Agreements Adrian Paschke 1 , Martin Bichler 1 , and Jens Dietrich 2 1 Internet-based Information Systems, Technische Universität München {Paschke,Bichler}@in.tum.de 2 Information Sciences & Technology, Massey University J.B.Dietrich@massey.ac.nz Abstract. In this paper we evolve a rule based approach to SLA representation and management which allows separating the contractual business logic from the application logic and enables automated execution and monitoring of SLA specifications. We make use of a set of knowledge representation (KR) con- cepts and combine adequate logical formalisms in one expressive formal framework called ContractLog. 1 Introduction Service Level Management (SLM) and Service Level Agreements (SLAs) are of growing commercial interest with a deep impact on the strategic and organisational processes as intensified interest in accepted management standards like ITIL 1 or the new BS15000 2 shows. Additionally, IT virtualisation and upcoming flexible IT infra- structures like e.g. new middleware products, storage area networks or grids services pave the way for new service oriented business models (e.g. “on-demand”, “pay-per- use”, “utility computing”) with flexible and more individual contracts. [1] This needs new levels of flexibility and automation in SLA management not available with the current technology and tools [2, 3]. This paper proposes a rule based representation of SLAs using sophisticated, logic-based knowledge representation (KR) concepts as an alternative to natural language defined contracts or pure procedural implementations in programming languages such as Java or C++. We combine selected adequate logi- cal formalisms in one expressive framework called ContractLog with which to de- scribe formal rule based contract specifications which can be automatically monitored and executed. The essential advantages of ContractLog are: 1. Contract rules are separated from the service management application. This allows easier maintenance and management and facilitates contract arrangements which are adaptable to meet changes to service requirements dynamically with the indispensable minimum of service execution disruption at runtime, even possibly permitting coexistence of differentiated contract variants. 1 IT Infrastructure Library (ITIL): www.itil.co.uk 2 BS15000 IT Service Management Standard: www.bs15000.org.uk