A White-Rabbit Network Interface Card For Synchronized Sensor Networks

White Rabbit (WR) is an Ethernet-based technology that provides data transfer and synchronization in sensor networks with a sub-nanosecond accuracy and a precision of 20 picoseconds. WR networks are composed of switches and nodes forming a tree hierarchical model where end-nodes are connected to different sensors and actuators whilst WR switches are intermediate elements that are used as time reference distributors through the whole network. WR networks access requires the utilization of specialized timing interfaces. To allow their utilization on commodity hardware, we have developed a White Rabbit Network Interface Card (WR-NIC). The WR-NIC is composed of a WR node provided with the proper gateware that can be plugged in a PCIe slot of a conventional computer and can be controlled by a Linux kernel driver as a standard network interface card (NIC). The same node allows a standalone operation mode thanks to the utilization of a C/C++ library called CALoE, which provides the device with remotely control features. This work describes the different WR-NIC features and all its elements.