In modern communication systems, it is necessary to develop new approaches to optimise them. To achieve this objective, new paradigms are necessary. The present work proposes the conception of an autonomic communication system, which is based on a Bayesian network and on an ontology, to take reconfiguration decisions in the system. The ontology provides the knowledge about the performance factors and their relationships in the communication networks, to configure the structure of the Bayesian network. The Bayesian network is the stochastic reasoning mechanism used by the decision-making system. We present several tests on the NS2 simulator, and we observe an improvement in the system performance, for scenarios with high reconfiguration requirements.