The present disclosure relates to a slice monitor for monitoring slices programmed by a slice owner and deployed by an orchestrator in the control and data planes of a communication network. The slice monitor comprises multiple databases containing different types of information, selects the probes to monitor each slice in the control plane or the data plane and instantiates the selected probes as well as a single-slice monitoring device specific to each slice. For optimization, the slice monitor configures the content of its databases by communicating through multiple interfaces with different actors such as the slice owner, the owner of the orchestrator and the owner of itself. Using alarm handlers and a reconfiguration engine, the slice monitor together with the single-slice monitoring device can detect and compensate for possible violations in the service-level agreement by reconfiguring the slice. If the compensation fails, the slice monitor requests the orchestrator for reconfiguration.