Policy specification and architecture for quality of service management

Abstract

An application's quality of service (QoS) requirements refers to non-functional, run-time requirements. These requirements are usually soft in that the application is functionally correct even if the QoS requirement is not satisfied at run-time. QoS requirements are dynamic in that for a specific application, they change. The ability to satisfy an application's QoS requirement depends on the available resources. Since an application may have different QoS requirements in different sessions, the resources needed are different. A differentiated service must be supported. Since an application's QoS requirement is soft, it may not always be satisfied. It must be possible to dynamically allocate more resources. In an overloaded situation, it may be necessary to allocate resources to an application at the expense of other applications. Policies are used to express QoS requirements and actions to be taken when the QoS requirement is not satisfied. Policies are also used to specify actions to be taken in overloaded situations. Policies dynamically change. Supporting these policies is done through a set of distributed managed processes. It must be possible specify policies and have these policies distributed to managed processes. This paper describes how these policies can be formally specified and a management architecture (based on the IETF framework) that describes how the policies are distributed and used by the management system. We conclude with a discussion of our experiences with the management system developed.