A white rabbit timing network consists of three important parts.
The IEEE1588 or the Precision Time Protocol is a time protocol designed to provide synchronization accuracy of 1 microsecond or even less, particularly for use in Industrial networks and Research labs where accurate synchronization is necessary. An accuracy of sub nanoseconds is ideally possible in PTP networks but, in practice, the master-slave and the slave-master links may be asymmetric and the resolution of the PTP time stamps is limited. Hence, the obtained synchronization accuracy in PTP networks is limited.
Just like the SyncE standard, the mechanism to operate all the nodes at the same frequency works at the physical layer level. Hence, there is no effect on data transfers because of this. The main idea of layer I syntonization is that the clocks in the network are not free running at a frequency, but instead, should be locked to a reference standard and be traceable. So, a network using Layer I syntonization has a hierarchy in the network: there is a master node which sends the frequency information in data streams and all other nodes in the system extract this information from the data stream and have a phase locked loop(PLL) which makes them run at exactly this frequency. This removes the jitter and frequency drift in the clocks that is responsible for the offset.
As explained before, the frequency of the local node is disciplined using the clock signal extracted from the data stream sent by the master node. Then, the local node sends back its local clock signal to the master. As the local and master clock frequencies are locked, this clock signal is just a delayed version of the master clock signal. By calculating the phase offset between these two signals, a very accurate measurement for the particular link delay could be made.
After finding the link delay, this could be used in the conventional PTP algorithm to achieve a very high accuracy.
Components of a White Rabbit network are multi-port White Rabbit Switches and single or dual-port White Rabbit nodes. Both components may be added dynamically to the network. Cable length and other delay factors are automatically compensated by the Precision Time Protocol algorithms. Though conventional Gigabit Ethernet devices may be connected as well, only White Rabbit devices take part in network timing and synchronization.