CC-Pi: A Constraint-Based Language for Specifying Service Level Agreements

Service Level Agreements (SLA) are a key issue in Service Oriented Computing. SLA contracts specify client requirements and service guarantees, with emphasis on Quality of Service (Cost, performance, availability, etc.). In this work the authors propose a simple model of contracts for QoS and SLAs that also allows to study mechanisms for resource allocation and for joining different SLA requirements. The language combines two basic programming paradigms: name-passing calculi and concurrent constraint programming (cc programming). Specifically, they extend cc programming by adding synchronous communication and by providing a treatment of names in terms of restriction and structural axioms closer to nominal calculi than to variables with existential quantification.