The promise of ontologies as a technique for knowledge representation is in the sharing of a common understanding of concepts between people and application systems. In the network management area this promise has already been demonstrated through the possibility to map various network management information models (such as SMI, CIM, or CMIP) into ontology language representations. Those ontology-based applications which can handle the common concepts will be able to achieve the interchange of management information in a heterogeneous environment. The discovery and use of semantic mappings between the ontological versions of different management models is set therefore to become an increasingly important part of management system engineering.Another important advantage of this approach is in the possibility to develop ontology language representations of the expected behaviour of the managed resources, in such a way that it can be interpreted by intelligent network managers in order to perform management tasks, independently of the native management mechanisms of the network resources. The goal of this thesis is to analyze the possibility to use ontologies for the representation of the different types of network management behaviour, and then define the mechanisms that will make use of these representations in an ontology-based network management framework, in order for a network management system to achieve interoperability between different management domains. These mechanisms will help network administrators by allowing for unified management behaviour definition, avoiding the current need to deal with independent information models and behaviour definitions for each domain. Ontology-based interoperability mechanisms between management domains with varying levels of abstraction can also be used to improve behaviour definition, in such a way that the administrator can focus on managing the infrastructure and services at an abstract level, instead of having to take care of the details of specific technology and device configuration.