Glossary · Automation fundamentals, platforms and components
White Rabbit
Also known as: White Rabbit PTP, High Accuracy profile
German: White Rabbit
White Rabbit is a technology for sub-nanosecond time synchronization over Ethernet, originally developed at CERN, that extends the Precision Time Protocol (PTP) with synchronous Ethernet and precise phase measurement. Its concepts were standardized as the High Accuracy option in IEEE 1588-2019.
- Automation components
- Standards
In one sentence
White Rabbit, developed at CERN, extends PTP over Ethernet to sub-nanosecond time synchronization; IEEE 1588-2019 adopted it as High Accuracy.
Example
A research facility distributes a common timebase to hundreds of measurement nodes over kilometers of fiber using White Rabbit switches.
How it applies
- Engineering: White Rabbit is used where standard PTP accuracy is not enough, such as particle accelerators, scientific facilities, power grid measurement and financial timing. Typical industrial automation needs are usually met by standard PTP profiles.
- Operation: Accuracy depends on compatible hardware along the path, fiber links and calibration of link asymmetry.
- Documentation: Specify the required accuracy of Time synchronization as a number and the reference (for example UTC), rather than naming a technology. When White Rabbit is used, document calibration values and the timing topology.
White Rabbit vs. standard PTP
Standard PTP (IEEE 1588) typically achieves sub-microsecond synchronization with suitable hardware. White Rabbit adds frequency distribution via synchronous Ethernet and phase detection to reach sub-nanosecond accuracy.