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Configure PTP Transparent Clock

This topic lists the steps to configure PTP transparent clock. Transparent clocks measure and adjust for packet delay. The transparent clock computes the variable delay as the PTP packets pass through the switch or the router.

A Precision Time Protocol (PTP) Transparent clock measures the residence time of PTP packets as they pass through router. This residence time is added to the Correction Field of the PTP packet.

In a distributed network, you can configure transparent clock for Precision Time Protocol (PTP) for synchronizing the timing across the network. Junos OS supports the e2e-transparent CLI statement at the [edit protocols ptp] hierarchy level to configure transparent clock for Precision Time Protocol (PTP).

The PTP transparent clock functionality is supported on PTP-over-IP and PTP-over-Ethernet (PTPoE).

Note:

When the IGMP snooping-enabled routers and switches that are configured with PTP Transparent clock fail to perform the IGMP snooping, use the static IGMP configuration to forward the PTP traffic.

Platform-Specific Transparent Clock Behavior

Use Feature Explorer to confirm platform and release support for specific features.

Use the following table to review platform-specific behaviors for your platform:

Table 1: Platform-Specific Behavior

Platform

Difference

ACX Series

  • ACX routers do not support PTPoE over VLANs when it works in ordinary clock or boundary clock mode.

  • Domain numbers—Transparent clock functionality would compute the residence time for PTP packets belonging to all domains.

  • PTP-over-MPLS—Transparent clock functionality do not support PTP carried over MPLS in ACX routers.

To configure a PTP transparent clock:

  1. Configure the clock mode:
  2. Configure the transparent clock:
  3. (Optional) To configure the syntonized-end-to-end (E2E) transparent clock for Precision Time Protocol (PTP) use the command provided below. Please note that SyncE must be enabled before enabling syntonized transparent clock.

Change History Table

Feature support is determined by the platform and release you are using. Use Feature Explorer to determine if a feature is supported on your platform.

Release
Description
change-completed
Starting in Junos OS Release 17.1 onwards, to configure transparent clock, include the e2e-transparent CLI command at the [edit protocols ptp] hierarchy level. Prior to Junos OS Release 17.1, to configure transparent clock, include the transparent-clock CLI command at the [edit protocols ptp] hierarchy level.