Frames received by a SmartNIC have variable latency from arriving at the SmartNIC and until the host processes the frames, due to SmartNIC buffers and delay in transfer to host. Frames are therefore provided with a time stamp showing the receive time in the SmartNIC, so the host has information about the original frame receive time.
Multiple NT SmartNICs can be synchronized in order to ensure that the time difference between the SmartNICs is small. The receive time of frames in different hosts on the same site, or hosts on different sites through the use of GPS, can thereby be compared. Different possible uses are shown in this section.
SmartNIC to SmartNIC
Direct time synchronization from one NT SmartNIC to another using either the external or the internal time synchronization connectors can be used to synchronize two SmartNICs as shown in this figure.
Daisy-chaining of SmartNICs
One NT SmartNIC can also synchronize a number of NT SmartNICs when the slave SmartNICs are daisy-chained as shown in this figure.