US Patent 10439712 System and methods for determining propagation delay

One aspect of the disclosure is directed to a system and method for determining the propagation delay for a signal to traverse an optical fiber between two transceivers. The method is performed by the first transceiver and includes transmitting a message to the second transceiver over a first optical fiber. The method further includes receiving on the first optical fiber a reply message from the second transceiver including an indication of the internal time for the second transceiver to transmit the reply message. The method further includes determining the time interval from the time the message was transmitted to the time the first transceiver received the reply message. The method further includes calculating the propagation delay from the time interval and the internal time. The method further includes configuring the first transceiver to receive data traffic from the second transceiver on a second optical fiber. Another aspect is directed to a system and method for using the determined propagation delay to synchronize the two transceivers.