Automated refinement of policies for network management

Policy-based management is a flexible approach for the management of networks as policies make context-sensitive and automated decisions. For their effective development it is desired to specify policies at a high level of abstraction initially and to refine them until they are represented in a machine-executable way. We present an approach that uses models to specify event-condition-action (ECA) policies at different abstraction layers and that uses model transformations to refine them in an automated way. A relational algebra is used to formally validate the models and define the semantics of the refinement process. One benefit of the approach is the automated policy refinement at runtime. Changes at the high-level models are automatically reflected in their low-level implementation through refinement. This allows to manage a system at a high level of abstraction. The approach is applied to the network management domain and demonstrated with policies for physical cell identification (PCI) in a mobile network. It can also be applied to other domains and supports a flexible number of abstraction layers.