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5. After sending the Pdelay_Resp message, the master clock sends a Pdelay_Resp_Follow_Up
message carrying time t5 immediately.
From the above process, the member clock collects six timestamps, t1 to t6, and obtains the
round-trip delay to the master clock by using the following calculation:
• [(t4 – t3) + (t6 – t5)]
The member clock also obtains the one-way delay by using the following calculation:
• [(t4 – t3) + (t6 – t5)] / 2
The offset between the member and master clocks is as follows:
• (t2 – t1) – [(t4 – t3) + (t6 – t5)] / 2
Depending on whether to send Follow_Up messages, the Peer Delay mechanism includes two
modes: single-step and two-step.
• In single-step mode, t1 is carried in the Sync message, and no Follow_Up message is sent. The
offset between t5 and t4 is carried in the Pdelay_Resp message, and no
Pdelay_Resp_Follow_Up message is sent.
• In two-step mode, t1 is carried in the Follow_Up message, and t4 and t5 are carried in the
Pdelay_Resp and Pdelay_Resp_Follow_Up messages.
Protocols and standards
• IEEE 1588-2008, IEEE Standard for a Precision Clock Synchronization Protocol for Networked
Measurement and Control Systems
• IEEE P802.1AS, Timing and Synchronization for Time-Sensitive Applications in Bridged Local
Area Networks
Configuring clock nodes
Before performing the following configurations, define the scope of the PTP domain and the role of
every clock node.
Configuration task list
Tasks at a glance
(Required.) Specifying a PTP standard
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