> But given that NTP (either ntpd or chrony) tends to give me an estimated error of around (tens of) 1e-6 seconds Is that a hard bound or an average? If it's

> But given that NTP (either ntpd or chrony) tends to give me an estimated error of around (tens of) 1e-6 seconds Is that a hard bound or an average? If it's an average, then what are the limits of the bounds, both in magnitude and duration? > and PTP can get down to 1e-9 seconds We use it for audio, and the reason it works well there is because there is no exponential backoff with your peers, allowing for even small timing slips to become enough to notice. 1ms of latency is far too much for our application, we typically aim for 0.25ms.. and we're only running 96kHz. If we lose PTP sync, we notice within a few minutes. Another advantage of PTP is it can operate as a broadcast and, as the article notes, switches can be PTP aware and help update the timing as the broadcast flows through the network. Conveniently, PTP also allows for multiple timing domains and masters to co-exist on the same network. It's also an absurdly simple protocol, you can build a receiver for it in about 200 lines of C code. I've actually become quite taken with it since it was forced into our space about 10 years ago.