In modern communication systems, it is necessary to develop new approaches to optimize them. To achieve this objective, new paradigms are necessary. The present work proposes an autonomic communication system, which uses a system of decision-making based on a Bayesian network, and a knowledge base based on an ontology, to take decisions of reconfiguration in the system. The main goal of the autonomic communication system is to adapt the communications platform to the characteristics of the context, in order to improve its performance. 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. In the tests carried out, we observe an improvement between 85% and 96% in the system performance, for scenarios where our approach of autonomic decision reconfigures the communication system.