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

PTP switch configuration

Updated: June 26, 2026

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Describes the procedures for configuring Precision Time Protocol (PTP) on network switches.

PTP switch configuration is a network setup process that enables Precision Time Protocol functionality on network switches to provide high-precision time synchronization across network devices.

Configuration procedures

Use one of the procedures in this section to configure the switch for PTP.

Note

To configure the switch for grandmaster-boundary clock mode (gmc-bc), see Configure NTP to PTP time conversion.

Note
On the ESS3300, the 10 GE ports do not support PTP. Only ports gi1/3-gi1-10 and gi2/1-gi2/16 support PTP.

Configure PTP power profile mode on the switch

This task enables you to configure the Precision Time Protocol (PTP) Power Profile on your switch, allowing it to participate in time synchronization networks with enhanced power grid applications support.

This section describes how to configure the switch to use the PTP Power Profile and operate in Power Profile mode.

Before you begin

These are some guidelines for configuring the Power Profile on the switch:

  • When you enter no with PTP port configuration commands, the specified port property is set to the default value.

  • To determine the value in seconds for the PTP global command interval variable, use a logarithmic scale. Below are examples of the interval variable value converted to seconds with a logarithmic scale:

Value Entered

Logarithmic Calculation

Value in Seconds

-1

2 -1

1/2

0

2 0

1

Follow these steps to configure PTP Power Profile mode on the switch:

Procedure

1.

Use the configure terminal command to enter global configuration mode. Then, enter the ptp profile power command to set the Power Profile.

Example:

Device(config)# ptp profile power
2.

Use the ptp {mode boundary pdelay-req | p2ptransparent | forward | gmc-bc} command to specify the synchronization clock mode.

Example:

Device(config)# ptp mode boundary pdelay-req

  • mode boundary pdelay-req —Configures the switch for boundary clock mode using the delay-request mechanism. In this mode, the switch participates in the selection of the most accurate time source clock. Use this mode when overload or heavy load conditions produce significant delay jitter.

  • mode p2ptransparent —Configures the switch for peer-to-peer transparent clock mode and synchronizes all switch ports with the time source clock. The link delay time between the participating PTP ports and the message transit time is added to the resident time. Use this mode to reduce jitter and error accumulation. This is the default in Power Profile mode.

  • mode forward —Configures the switch to pass incoming PTP packets as normal multicast traffic.

  • mode gmc-bc —Configures the switch for grandmaster-boundary clock mode. See Configuring NTP to PTP Time Conversion to configure the switch for this mode.
3.

(Optional) Use the ptp allow-without-tlv command to specify TLV settings for BC and TC modes.

Example:

Device(config)# ptp allow-without-tlv
Note

Using this command when switch mode is p2ptransparent allows the switch to operate in PTP networks where IEC61850-9-3 is required.
4.

(Optional) Use the ptp domain domain-number command to specify the PTP clock domain for BC and TC modes.

Example:

Device(config)# ptp domain 10

domain-number—A number from 0 to 255.

The participating grandmaster clock, switches, and time recipient devices should be in the same domain.
5.

(Optional) Use the ptp packet priority command to specify the packet priority for BC and TC modes.

Example:

Device(config)# ptp packet priority 4

The PTP packets have a default priority of 4.
6.

(Optional) Use the ptp priority1 priority priority2 priority command to specify the BMCA priority for BC mode.

Example:

Device(config)# ptp priority1 100 priority2 100

  • priority1 priority— Overrides the default criteria (such as clock quality and clock class) for the most accurate time source clock selection.

  • priority2 priority— Breaks the tie between two switches that match the default criteria. For example, enter 2 to give a switch priority over identical switches.

  • priority — A priority number from 0 to 255. The default is 128.

Note

A lower value has higher priority.
7.

(Optional) Use the ptp time-property persist {value | infinite} command to specify time-property preservation for BC mode.

Example:

Device(config)# ptp time-property persist infinite

  • value— Time duration, in seconds, from 0-100000. The default is 300.

  • infinite — Time properties are preserved indefinitely.

Preserving the time properties prevents time recipient clocks from detecting a variance in the time values when the redundant GMC comes out of standby.
8.

(Optional) Use the ptp transfer {feedforward | filter linear} command to specify the BC synchronization algorithm.

Example:

Device(config)# ptp transfer feedforward

  • feedforward —Very fast and accurate. No PDV filtering.

  • filter linear —Provides a simple linear filter (default).
9.

(Optional) Use the interface interface-id command to enter interface configuration mode. Then, use the ptp command to specify port settings.

Example:

Device(config-if)# ptp enable

Boundary pdelay-req mode:

ptp {announce {interval value | timeout value } | pdelay-req interval value | enable | sync {interval value | limit value } | vlan value }

p2ptransparent mode:

ptp {pdelay-req interval value | enable | sync limit value | vlan value }

  • announce interval value —Sets the logarithmic mean interval in seconds to send announce messages. The range is 0 to 4. The default is 1 (2 seconds).

  • announce timeout value —Sets the logarithmic mean interval in seconds to announce timeout messages. The range is 2 to 10. The default is 3 (8 seconds).

  • pdelay-req interval value —Sets the logarithmic mean interval in seconds for time recipient devices to send pdelay request messages when the port is in the time source clock state. The range is -3 to 5. The default is 0 (1 second).

  • enable —Enables PTP on the port base module.

  • sync interval value —Sets the logarithmic mean interval in seconds to send synchronization messages. The range is –2 to 1. The default is 1 second.

  • sync limit value —Sets the maximum clock offset value before PTP attempts to resynchronize. The range is from 50 to 500000000 nanoseconds. The default is 10000 nanoseconds.

  • vlan value —Sets the PTP VLAN on a trunk port. The range is from 1 to 4094. The default is the native VLAN of the trunk port. In boundary mode, only PTP packets in PTP VLAN will be processed, PTP packets from other VLANs will be dropped. Before configuring the PTP VLAN on an interface, the PTP VLAN must be created and allowed on the trunk port.

The switch is configured with PTP Power Profile mode and will participate in time synchronization according to the specified clock mode and settings. The configuration is active and ready to synchronize with other PTP devices in the network.

The following example configures the switch for P2P transparent mode (the default in Power Profile mode), specifies allow-without-tlv PTP message processing, and uses default values for all PTP interval settings:

Device(config)# ptp allow-without-tlv

The following example configures the switch for boundary clock mode using the peer delay request (pdelay-req) mechanism and uses default values for all PTP interval settings:

Device(config)# ptp mode boundary pdelay-req

Configure default profile mode on the switch

Configure the switch to operate in Default Profile mode to enable proper PTP packet handling and time synchronization in your network environment.

This section describes how to configure the switch to operate in Default Profile mode.

The switch sends untagged PTP packets on the native VLAN when the switch port connected to the grandmaster clock is configured as follows:

  • Switch is in Default Profile mode.

  • Switch is in trunk mode.

  • VLAN X is configured as the native VLAN.

When the grandmaster clock requires tagged packets, make one of the following configuration changes:

  • Force the switch to send tagged frames by entering the global vlan dot1q tag native command.

  • Configure the grandmaster clock to send and receive untagged packets. If you make this configuration change on the grandmaster clock, you can configure the switch port as an access port.

Before you begin

These are some guidelines for configuring the Default Profile on the switch:

  • When you enter no with PTP port configuration commands, the specified port property is set to the default value.

  • To determine the value in seconds for the PTP global command interval variable, use a logarithmic scale. Below are examples of the interval variable value converted to seconds with a logarithmic scale:

Value Entered

Logarithmic Calculation

Value in Seconds

-1

2 -1

1/2

0

2 0

1

Follow these steps to configure Default Profile mode on the switch:

Procedure

1.

Use the configure terminal command to enter global configuration mode. Then, use the ptp {mode boundary delay-req | e2etransparent | forward | gmc-bc} command to specify the synchronization clock mode.

Example:

Device(config)# ptp mode boundary delay-req

  • mode boundary delay-req —Configures the switch for boundary clock mode using the delay-request mechanism. In this mode, the switch participates in the selection of the most accurate time source clock. Use this mode when overload or heavy load conditions produce significant delay jitter.

  • mode e2etransparent —Configures the switch for end-to-end transparent clock mode. A switch clock in this mode synchronizes all switch ports with the time source clock. This switch does not participate in time source clock selection and uses the default PTP clock mode on all ports. This is the default clock mode. The message transit time is added to the resident time. Use this mode to reduce jitter and error accumulation.

  • mode forward —Configures the switch to pass incoming PTP packets as normal multicast traffic.

  • mode gmc-bc —Configures the switch for grandmaster-boundary clock mode. See Configure NTP to PTP time conversion to configure the switch for this mode.
2.

(Optional) Use the ptp domain domain-number command to specify the PTP clock domain for BC and TC modes.

Example:

Device(config)# ptp domain 10

domain-number — A number from 0 to 255.

The participating grandmaster clock, switches, and time recipient devices should be in the same domain.
3.

(Optional) Use the ptp priority1 priority priority2 priority command to specify the BMCA priority for BC mode.

Example:

Device(config)# ptp priority1 100 priority2 100

  • priority1 priority— Overrides the default criteria (such as clock quality and clock class) for the most accurate time source clock selection.

  • priority2 priority— Breaks the tie between two switches that match the default criteria. For example, enter 2 to give a switch priority over identical switches.priority — A priority number from 0 to 255. The default is 128.
4.

(Optional) Use the ptp time-property persist {value | infinite} command to specify time-property preservation for BC mode.

Example:

Device(config)# ptp time-property persist infinite

  • value— Time duration, in seconds, from 0-100000. The default is 300.

  • infinite— Time properties are preserved indefinitely.

Preserving the time properties prevents time recipient clocks from detecting a variance in the time values when the redundant GMC comes out of standby.
5.

(Optional) Use the ptp transfer {feedforward | filter {adaptive | linear}} command to specify the BC synchronization algorithm.

Example:

Device(config)# ptp transfer feedforward

  • feedforward —Very fast and accurate. No PDV filtering.

  • filter adaptive —Automatically filters as much PDV as possible.

  • filter linear —Provides a simple linear filter (default).
6.

(Optional) Use the interface interface-id command to enter interface configuration mode. Then, use the ptp command to specify port settings.

Example:

Device(config-if)# ptp enable

Boundary delay-req mode:

ptp {announce {interval value | timeout value } | delay-req interval value | enable | sync {interval value | limit value } | vlan value }

e2etransparent mode:

ptp {enable | sync {interval value | limit value }}

  • announce interval value —Sets the logarithmic mean interval in seconds to send announce messages. The range is 0 to 4. The default is 1 (2 seconds).

  • announce timeout value — Sets the logarithmic mean interval in seconds to announce timeout messages. The range is 2 to 10. The default is 3 (8 seconds).

  • delay-req interval value —Sets the logarithmic mean interval in seconds for time recipient devices to send delay request messages when the port is in the time source clock state. The range is -2 to 6. The default is -5 (1 packet every 1/32 seconds, or 32 packets per second).

  • enable —Enables PTP on the port base module.

  • sync interval value —Sets the logarithmic mean interval in seconds to send synchronization messages. The range is –2 to 1. The default is 1 second.

  • sync limit value —Sets the maximum clock offset value before PTP attempts to resynchronize. The range is from 50 to 500000000 nanoseconds. The default is 500000000 nanoseconds.

  • vlan value —Sets the PTP VLAN on a trunk port. The range is from 1 to 4094. The default is the native VLAN of the trunk port. In boundary mode, only PTP packets in PTP VLAN will be processed, PTP packets from other VLANs will be dropped. Before configuring the PTP VLAN on an interface, the PTP VLAN must be created and allowed on the trunk port.
7.

Use the end command to return to privileged EXEC mode.

Example:

Device(config-if)# end
8.

(Optional) Use the show running-config command to verify your entries.

Example:

Device# show running-config
9.

(Optional) Use the copy running-config startup-config command to save your entries in the configuration file.

Example:

Device# copy running-config startup-config

The switch is configured for Default Profile mode with the specified synchronization clock mode and optional settings. PTP packets are handled according to the configured mode and VLAN settings.

Verify configuration

Use the show PTP commands to verify and display various PTP configuration properties including clock information, foreign master records, parent properties, port settings, and time properties.

Command

Purpose

show PTP {clock|foreign-master-records|parent|port{FastEthernet|GigabitEthernet} | time-property} | histogram | history | internal-info

Identifies the type of PTP information to display.

  • clock—Displays PTP clock information.

  • foreign-master-records—Displays PTP foreign-master-records.

  • parent—Displays PTP parent properties.

  • port FastEthernet—Displays PTP properties for the FastEthernet IEEE 802.3 interfaces.

  • port GigabitEthernet—Displays PTP properties for the GigabitEthernet IEEE 802.3z interfaces.

  • time-property—Displays PTP clock-time properties.

  • histogram—Displays PTP offset, delay, or time-error data.

  • history—Displays PTP historical data.

  • internal-info—Displays PTP offset.

Power profile example


switch# show ptp parent
 PTP PARENT PROPERTIES
  Parent Clock:
  Parent Clock Identity: 0xA4:C:C3:FF:FE:BF:B4:0
  Parent Port Number: 23
  Observed Parent Offset (log variance): N/A
  Observed Parent Clock Phase Change Rate: N/A
  Grandmaster Clock:
  Grandmaster Clock Identity: 0xA4:C:C3:FF:FE:BF:2B:0
  Grandmaster Clock Quality:
        Class: 248
        Accuracy: Unknown
        Offset (log variance): N/A
        Priority1: 128
        Priority2: 128
switch# show ptp clock
 PTP CLOCK INFO
  PTP Device Type: Boundary clock
  PTP Device Profile: Power Profile
  Clock Identity: 0xA4:C:C3:FF:FE:BF:E0:80
  Clock Domain: 0
  Number of PTP ports: 26
  PTP Packet priority: 4
  Priority1: 128
  Priority2: 128
  Clock Quality:
        Class: 248
        Accuracy: Unknown
        Offset (log variance): N/A
  Offset From Master(ns): 25
  Mean Path Delay(ns): 705
  Steps Removed: 4
  Local clock time: 14:23:56 PST Apr 5 2013
switch# show ptp foreign-master-record
PTP FOREIGN MASTER RECORDS
 Interface GigabitEthernet1/1
   Foreign master port identity: clock id: 0xF4:4E:5:FF:FE:E5:82:0
   Foreign master port identity: port num: 1
   Number of Announce messages: 4
   Message received port: 1
   Time stamps: 1999872004, 1999870997
 Interface GigabitEthernet1/2
   Empty
 Interface GigabitEthernet1/3
   Empty
 Interface GigabitEthernet1/4
   Empty
 Interface GigabitEthernet1/5
   Empty
 Interface GigabitEthernet1/6
   Empty
 Interface GigabitEthernet1/7
   Empty
 Interface GigabitEthernet1/8
   Empty
 Interface GigabitEthernet1/9
   Empty
switch#
switch# show ptp ?
  clock                  show ptp clock information
  foreign-master-record  show PTP foreign master records
  parent                 show PTP parent properties
  port                   show PTP port properties
  time-property          show PTP clock time property
switch# show ptp time-property
 PTP CLOCK TIME PROPERTY
  Current UTC offset valid: 0
  Current UTC offset: 35
  Leap 59: 0
  Leap 61: 0
  Time Traceable: 16
  Frequency Traceable: 32
  PTP Timescale: 1
  Time Source: Internal Oscillator
  Time Property Persistence: 300 seconds
switch# show ptp port GigabitEthernet 1/1
PTP PORT DATASET: GigabitEthernet1/1
  Port identity: clock identity: 0xF4:4E:5:FF:FE:E5:91:80
  Port identity: port number: 1
  PTP version: 2
  Port state: UNCALIBRATED
  Delay request interval(log mean): 5
  Announce receipt time out: 3
  Peer mean path delay(ns): 0
  Announce interval(log mean): 0
  Sync interval(log mean): 0
  Delay Mechanism: Peer to Peer
  Peer delay request interval(log mean): 0
  Sync fault limit: 500000000
switch#

Configuration example

This reference provides configuration examples for various PTP (Precision Time Protocol) modes including P2P transparent mode, boundary clock mode, and end-to-end transparent mode with their respective settings and commands.

This example configures the switch for P2P transparent mode, specifies allow-without-tlv PTP message processing, and uses default values for all PTP interval settings:

Note

The commands work only in power profile.


Device(config)# ptp mode p2ptransparent
Device(config)# ptp allow-without-tlv

This example configures the switch for boundary clock mode using the peer delay request (pdelay-req ) mechanism and uses default values for all PTP interval settings:


Device(config)# ptp mode boundary pdelay-req

This example configures the switch to operate in Default Profile mode and end-to-end transparent mode and uses default values for all PTP interval settings:


Device(config)# no ptp profile
Device(config)# ptp mode e2etransparent

This example configures the switch for Default Profile mode and boundary clock mode with the delay-request mechanism, and uses default values for all PTP interval settings:


Device(config)# no ptp profile
Device(config)# ptp mode boundary delay-req