https://white-rabbit.web.cern.ch/
Cern The White Rabbit Project
The White Rabbit Project is a multilaboratory, multicompany and multinational collaboration to develop new technology that provides a versatile solution for control and data acquisition systems. The project was started within an effort to renovate the current CERN control and timing system. Since then, it has expanded beyond this initial application. One of the reasons for such expansion is the open source paradigm used in the project for the development of hardware, gateware and software. Another reason is the compatibility with standards.
The White Rabbit Network is based on existing IEEE standards while extending these standards in a backward-compatible way if needed to meet CERN's requirement. Technically, the White Rabbit Network is a Bridged Local Area Network with VLANs (IEEE 802.1Q) that uses Ethernet (IEEE 802.3) to interconnect switches and nodes, and the Precision Time Protocol (PTP, IEEE 1588-2008) to synchronise them.
The main features of the White Rabbit Network are:
sub-nanosecond accuracy and picoseconds precision of synchronization
connecting thousands of nodes
typical distances of 10 km between network elements
Gigabit rate of data transfer
fully open hardware, firmware and software
commercial availability from many vendors
The high accuracy of synchronization in White Rabbit is achieved by extending the Precision Time Protocol (PTP, IEEE 1588-2008). This extension has been incorporated into the new revision of IEEE 1588 standard by the P1588 Working Group, see the White Rabbit Standardization project for more details.