International field trial demonstrates high-precision timing measurements directly from existing White Rabbit infrastructure.
SURF has successfully tested a new open-source White Rabbit monitoring feature that enables timing differences between network links to be measured with picosecond-level precision directly on White Rabbit switches. The feature was evaluated during an international field trial with SIKT and NORDUnet, using several hundred kilometers of existing fibre infrastructure and SURF’s live DWDM production network. SURF, connected in Hamburg through NORDUnet to the Nordic Timing Pilot.
The new functionality extends timing monitoring beyond the traditional upstream White Rabbit link. It makes it possible to monitor additional links, redundant paths and multiple timing sources directly from the White Rabbit infrastructure.Because the measurements are performed by the White Rabbit switches themselves, no additional dedicated measurement equipment is required for the monitoring function. This reduces both cost and operational complexity, particularly in distributed timing networks.
Comparing national time scales
During the field trial, White Rabbit switches running a beta version of the new firmware were used as part of a comparison between the time scales of VSL, the National Metrology Institute of the Netherlands, and RISE, the Swedish National Metrology Institute.
The trial demonstrated that the new functionality can perform picosecond-level timing monitoring in an operational network environment.The basis for the feature was originally developed by VU Amsterdam. SURF is working with its member institutions to bring research innovations into operational networks.
The White Rabbit Collaboration Bureau is now preparing the functionality for inclusion in a the latest version of the official release of the open-source White Rabbit Switch firmware. As a member of the White Rabbit Collaboration, SURF contributes by testing new developments in operational network environments and providing practical experience to the wider White Rabbit community.
“By performing these measurements directly on the White Rabbit switches, we can monitor timing differences with picosecond-level precision without additional dedicated measurement equipment,” said Paul Klop, Optical Network Architect at SURF. “The same approach can be used for individual links, redundant paths and larger distributed timing networks, making high-precision timing monitoring simpler and more cost-effective.”
