Most onboard embedded systems have real-time requirements. The SpaceFibre standard is developed for onboard local networks. However, the current version of the SpaceFibre standard does not specify any time synchronization mechanisms. The authors consider the mechanisms of time synchronization that are used in the data transmission standards, which are currently used for networks with real-time requirements. In the paper, the authors proposed possible time synchronization mechanisms for the SpaceFibre network, evaluate their characteristics. The authors proposed dynamically reconfigurable Local time controller for implementation of these mechanisms with ASIC.