A method of transmitting a data packet from a first data processing device toward a second data processing device, the first and second data processing devices being communicably connectable to one another via respective first and second interface devices and over an optical network includes determining a communication path in the optical network to communicably connect the first data processing device to the second data processing device, accessing, by a coordination module communicably connected to the first interface device, a pre-determined training sequence, transmitting, by the coordination module and over the communication path, the pre-determined training sequence to cause the second interface device to recover a signal clock from the pre-determined training sequence and transmitting, by the first data processing device, the data packet toward the second processing device over the communication path. A coordination module implements the method in a computing unit.