QoS assessment of providers with complex behaviours: An expectation-based approach with confidence

Abstract

Service Level Agreements (SLAs) define a set of consumer expectations which must be met by a provider if a contract is not to be broken. Since providers will potentially be providing many different services to thousands of different consumers, they must adopt an efficient policy for resource management which differentiates consumers into service ranges. Existing approaches to QoS assessment of providers assume that the policy of a provider with respect to consumers is handled on an individual basis. We maintain that such approaches are ineffective when providers adopt a policy based on service differentiation and in response introduce and evaluate an expectation-based approach to QoS assessment which presupposes the classification of consumers into ranges defined by their expectation. As well as carrying out assessment to determine the likely future behaviour of a provider for a given consumer expectation, we attach a confidence value to our assessment to indicate the level of certainty that the result is accurate. Our results suggest that our confidence-based approach can help consumers make better informed decisions in order to find the providers that best meet their needs. © 2006 Springer-Verlag.