Distributed picosecond-level time offset monitoring in White Rabbit High Accuracy synchronization networks in a datacenter scenario

Datacenter environments are gaining an increasing presence in most technology sectors due to the progressive move of information systems to the cloud. The main drivers for this transition are the lower cost of operating in a shared infrastructure, the reliability and availability of public clouds and the convenience of a software-based management of the networking infrastructure.This trend is pushing the conversion from private clouds to public clouds for most non-regulated applications which do not require strict levels of performance or security. Hybrid clouds, where part of the infrastructure is deployed in private locations and interface with public clouds, or colocations within the datacenter are also common in sectors like finance, health or companies with strict cybersecurity or confidentiality requirements. Additionally, multiple distributed applications like telecom or utility networks have centralized their services in the datacenter while maintaining distributed access networks nationwide.Following the requirements of the applications with an increasing footprint in the datacenter, time synchronization needs have evolved in terms of accuracy, scalability, reliability and monitoring. In this paper, we present a novel technique which allows White Rabbit devices to measure the offset between their local synchronized clock and several distributed time sources with picosecond-level resolution leveraging their sub-nanosecond time synchronization accuracy.In order to demonstrate the unprecedent capabilities of this technique, the paper showcases multiple experiments where multiple White Rabbit and external Pulse Per Second and clock inputs are evaluated in the laboratory and in a real-life interconnection between two datacenters in a metro area.