> services disseminate UTC-traceable time over managed fibre links using the Precision Time Protocol (PTP version 2, defined in the standard IEEE 1588-2008) [...] with an SLA of one microsecond to UTC

https://datatracker.ietf.org/doc/html/rfc8173

> This memo defines [MIB] objects for managing networks using the Precision Time Protocol (PTP), specified in IEEE Std. 1588-2008.