Systems and methods are provided to use of out-of-band (OOB) channels for the transport of network-synchronization signals and network control information. These OOB channels transport synchronization and control channels over low-frequency bands outside of the frequency bands used for the data channels. Locating expensive network-synchronization functions in the optical network unit (ONU) and sharing the derived synchronization signals among multiple downstream customer premises equipment (CPE) devices results in cost savings and provides a means for maintaining a continuous, end-to-end synchronization reference, even during periods when the data channels on the copper network segment are in an energy-efficiency mode (e.g., a low-power and/or sleep mode).