I came across this:
Interesting read for this community perhaps.
It’s interesting hardware, but the NTP performance they show (around 40 microseconds) is a bit disappointing. I suspect they didn’t enable hardware timestamping or interleaved mode.
An older Raspberry Pi with ethernet on USB can perform better than that. Here is a test I did some time ago:
With the Mellanox card they used I’d expect the error to stay below 1 microsecond. For example, this is a test with the Intel I210 (one of the few cards that has a PPS input/output):
Several switches would add some asymmetry and jitter, but not as much as they show in their test, so I think there were some software timestamps involved.
If anyone is interested, I have tested a number of other stratum-1 servers. The results are here: NTP server tests.
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