System Management Configuration Guide, Cisco Catalyst IE3x00 Rugged, IE3400 Heavy Duty, and ESS3300 Series Switches

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System Management Configuration Guide, Cisco Catalyst IE3x00 Rugged, IE3400 Heavy Duty, and ESS3300 Series Switches

Configuring PTP over DLR

Updated: June 26, 2026

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Describes the process of configuring Precision Time Protocol (PTP) over Device Level Ring (DLR) networks to achieve time synchronization across industrial Ethernet devices in ring topology configurations.

Recommendation: prerequisites for configuring precision time protocol

Configure PTP and DLR. Then implement the configuration commands in this section.

For information about PTP, DLR, and configuration instructions, refer to the documentation on cisco.com.

  • PTP: See the chapter "Configuring Precision Time Protocol" in this guide.

  • DLR: See the chapter "Device Level Ring" in the Redundancy Protocol Configuration Guide, Cisco Catalyst IE3x00 and IE3100 Rugged, IE3400 Heavy Duty, and ESS3300 Series Switches.

Set PTP transparent clock mode

This task configures PTP transparent clock mode on the switch with multi-VLAN support to enable precise time protocol functionality across multiple VLANs.

Use this procedure to enable PTP transparent clock mode with multi-VLAN support on the switch to achieve precise time synchronization across network segments.

Procedure

  1. Use the configure terminal command to enter global configuration mode.

    Example:

    Device# configure terminal

  2. Use the ptp mode e2etransparent multiple-vlan command to configure PTP transparent clock mode with multi-VLAN support.

    Example:

    Device(config)# ptp mode e2etransparent multiple-vlan

  3. Use the end command to return to privileged EXEC mode.

    Example:

    Device(config)# end

  4. (Optional) Use the show running-config | include ptp command to verify the PTP configuration.

    Example:

    Device# show running-config | include ptp

Configure the PTP interface

This task configures the PTP interface to enable VLAN selection for PTP packet transmission and reception on trunk ports.

Configure the PTP interface to allow users to choose which VLAN to use to transmit and receive PTP packets on a trunk port.

Before you begin

Create the required PTP VLAN using the vlan vlan_id command. The PTP VLAN also must be allowed on the trunk port.

Follow these steps to configure the PTP interface:

Procedure

  1. Use the configure terminal command to enter global configuration mode.

    Example:

    Device# configure terminal

  2. Use the vlan vlan-id command to create the PTP VLAN.

    Example:

    Device(config)# vlan 20

  3. Use the exit command to return to global configuration mode.

    Example:

    Device(config-vlan)# exit

  4. Use the interface interface-id command to enter interface configuration mode.

    Example:

    Device(config)# interface gigabitethernet 2/3

  5. Use the switchport mode trunk command to configure the interface as a trunk port.

    Example:

    Device(config-if)# switchport mode trunk

  6. Use the switchport trunk allowed vlan add vlan-id command to allow the PTP VLAN on the trunk port.

    Example:

    Device(config-if)# switchport trunk allowed vlan add 20

  7. Use the ptp vlan vlan-id command to configure the VLAN used to transmit and receive PTP packets on the trunk port.

    Example:

    Device(config-if)# ptp vlan 20

  8. Use the end command to return to privileged EXEC mode.

    Example:

    Device(config-if)# end