PTP

The device supports end-to-end and peer-to-peer transparent clocks.

End-to-end ( E2E) transparent clocks forward PTP messages, measure the residence time of PTP event message at the transparent clock, and add this residence time to the correction field of the PTP messages. Transparent clock timestamps the event messages on ingress and egress port. The difference between these timestamps is the residence time within the transparent clock. End-to-end transparent clocks will not execute port state machine and BMC algorithm to select the state of the port.

End-to-end transparent clocks may be used as a network element, or they may be associated with application devices such as sensors or actuators if an ordinary clock is combined with the end-to-end transparent clock.

Peer-to-peer transparent clock differs from the end-to-end transparent clock in the way it corrects and handles the timing messages. End-to-end transparent clock time stamps all PTP timing messages; peer-to-peer transparent clock forwards only Sync and Follow-up messages.

Peer-to-peer transparent clock calculates the residence time of PTP messages in peer-to-peer transparent clock, measures the link delay of the ingress port of PTP messages, and adds this correction field in the PTP messages. Peer-to-peer transparent clock uses Pdelay request-response mechanism to measure the link delay. It uses rate estimation and control mechanism to avoid the residence time error.

The following sections describe all PTP CLI configuration commands including show and debug ptp.