PTP 1-step Boundary Clock (or 1-step BC) is similar to 2-step BC in function, but doesn’t send the PTP Follow_Up message. The timestamp present in the PTP Follow_Up message’s preciseOriginTimestamp field is sent in the PTP Sync message’s originTimestamp field along with a non-zero correctionField.

This feature supports counting ECN marked packets (ECN Explicit Congestion Notification) on a per egress port per tx