White Rabbit -> Overview
White Rabbit (WR) is a solution to the generic problem of transferring data in a fast, deterministic and safe manner. Although its initial scope is mainly targeted at timing systems for experimental physics facilities, care has been taken to come up with a solution which is as generic as possible. White Rabbit is able to synchronize ~1000 nodes with sub-ns accuracy over fiber lengths of up to 10 km. The main technologies used are physical layer syntonization (clock recovery) and PTP (IEEE 1588). Compliance with established standards such as Ethernet and PTP is a key goal of the project.
The White Rabbit project is an on-going collaborative project for which first generation components have been designed and evaluated for use in real, mostly scientific, applications. The list of users is expanding rapidly with metrological institutes and astronomical observation centres evaluating White Rabbit.
The hardware design for the White Rabbit switch is licensed under the CERN Open Hardware Licence while the firmware and driver software also is available under "open" licences.
White Rabbit overview
White Rabbit (WR) is an extension to Ethernet technology developed in collaboration with many institutes and companies. It allows users to synchronize remote pieces of equipment to within one billionth of a second (1 nanosecond).
The project is completely based on free software and Open Source Hardware. Users of WR technology can purchase equipment from commercial vendors. This combination of open source and commercial approaches allows users to build on top of well-supported solutions without any risk of vendor lock-in.
WR benefits from a vibrant diverse community of developers and users. Because many eyes look at designs, bugs get identified early and fixed promptly. Also, as often happens with open source developments, WR has found uses in areas which are very removed from accelerator control systems. Groups in the Netherlands and Finland are exploring ways of using WR to disseminate official time. They have therefore contributed to the WR effort in order to extend its range from the few km into the hundreds of km realm. Other groups have developed extremely robust WR hardware because they need it to operate in extreme conditions. One example is the WR-based timing system of the HiSCORE Gamma and Cosmic Ray detector in the Tunka valley in Siberia. The KM3NeT neutrino detector provides for an even more dramatic setting: WR nodes have been recently deployed 100 km into Mediterranean Sea off the coast of Italy, at a water depth of 3500 m.
Precise network synchronization is a very active area of development worldwide. Recognizing the performance benefits of WR technology, the IEEE 1588 working group is currently working on a new revision of the standard which includes an effort to take concepts from WR. This will allow the IEEE 1588 standard to tackle synchronization applications in the nanosecond realm.
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- Users of White Rabbit Technology
General questions about the project
- Erik van der Bij - CERN
24 October 2017