SLA Tool

Abstract

Service level agreements (SLAs) specify commitments between providers and users of services. Concerning quantitative aspects it is common to guarantee response times under a maximal load. Often simulation models are used to validate those guarantees. The SLA calculus offers an efficient technique to establish and validate quantitative aspects of service level agreements. Based on bounds for the load and response times of single services, bounds for the response times of composed services can be calculated. Additionally, the SLA calculus determines bounds for the service capacities which the provider needs in order to fulfill the service level agreements. This paper describes the SLA Tool which supports the calculation of such bounds using results from +-algebra. The tool consists of two parts: Octave functions, that implement the operators of the SLA calculus, and a graphical user interface (GUI) which facilitates their use also for users not familiar with the theory. In the following we concentrate on the user interface.