A data communication network may, include a first sub-network and a second sub-network. The first sub-network may include two or more two master clocks, and a synchronization system connected to the master clocks. The synchronization system may, for determine a time-base for the master clocks and control the master clocks based on the determined time-base. The first sub-network may include one or more slave synchronization data source for generating slave clock synchronization data derived from time information of the master clocks. The second sub-network may include one or more slave clocks and a slave clock time-base controller connected to the slave synchronization data source. The time-base controller may receive the slave clock synchronization data and control one or more of the one or more slave clocks in accordance with the slave clock synchronization data.