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Timing and Synchronization Guide
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Example: Configure Hybrid Mode and ESMC Quality-Level Mapping on ACX Series Router

date_range 20-Dec-24

This example shows the configuration of hybrid mode by mapping the PTP clock class to the ESMC quality level and also by configuring a user-defined mapping of the PTP clock class to the ESMC quality level on ACX Series Routers.

Requirements for Hybrid Mode Configuration

This example uses the following hardware and software components:

  • One ACX Series router

  • Junos OS Release 12.2R2 or later

Overview

The combined operation of Synchronous Ethernet and Precision Time Protocol (PTP) is also known as hybrid mode. In hybrid mode, the synchronous Ethernet equipment clock (EEC) on the Modular Port Concentrator (MPC) derives the frequency from Synchronous Ethernet and the phase and time of day from PTP.

You can configure hybrid mode on ACX Series routers. On these routers, the combined operation is possible only when the PTP timeReceiver and the Synchronous Ethernet source are on the same device and are traceable to the same timeTransmitter. When acting as a PTP timeReceiver, the router can accept any external Synchronous Ethernet clock as reference. Note that when the selected Synchronous Ethernet reference fails, the router continues to work in PTP mode.

Hybrid mode is configured on the timeReceiver. On the timeReceiver, one or more interfaces are configured as Synchronous Ethernet source interfaces.

Note:

You can set the values for each parameter according to your requirement. The values given in this example are for illustration purposes only.

The ESMC quality level value is mapped to the clock class value either by mapping the PTP clock class to the ESMC quality level or by configuring a user-defined mapping of the PTP clock class to the ESMC quality level. The following examples explain configuring hybrid mode with either of the modes in detail.

To configure the router in hybrid mode, you must:

  1. Configure Synchronous Ethernet options at the [edit chassis synchronization] hierarchy level:

    • Configure the auto-select mode of operation. You can select the clock source either from a free-run local oscillator or from an external qualified clock.

      When the router is configured with the auto-select option, the router chooses up to two best upstream clock sources. It then uses the clock recovered from one of the sources to lock the chassis clock. If an upstream clock with acceptable quality is not available or if the router is configured in free-run mode, the router uses the internal oscillator.

    • Configure the esmc-transmit and network-option options at the [edit chassis synchronization] hierarchy level.

    • Configure one or more interfaces at the [edit chassis synchronization] hierarchy level as Synchronous Ethernet sources as needed.

  2. Configure PTP options at the [edit protocols ptp] hierarchy level.

  3. Configure hybrid mode options at the [edit protocols ptp slave] hierarchy level.

The following example requires you to navigate various levels in the configuration hierarchy. For instructions on how to do that, see Use the CLI Editor in Configuration Mode.

Configuration

Hybrid Mode with Mapping of the PTP Clock Class to the ESMC Quality-Level

CLI Quick Configuration

To quickly configure hybrid mode on the ge-1/2/3.0 interface with the clock source IP address as 2.2.2.2, copy the following commands, paste them in a text file, remove any line breaks, and then copy and paste the commands into the CLI.

content_copy zoom_out_map
[edit]
set protocols ptp slave hybrid
set protocols ptp slave interface ge-1/2/3.0 unicast-mode clock-source 2.2.2.2
set protocols ptp slave convert-clock-class-to-quality-level

Step-by-Step Procedure

To configure hybrid mode on an ACX Series router with mapping of the PTP clock class to the ESMC quality level, perform the following steps:

  1. Configure the convert-clock-class-to-quality-level option on the timeReceiver at the [edit protocols ptp slave] hierarchy level.

    content_copy zoom_out_map
    [edit protocols ptp slave]
    user@host# set convert-clock-class-to-quality-level
    
  2. Configure hybrid mode on the timeReceiver.

    content_copy zoom_out_map
    [edit protocols ptp slave]
    user@host# edit hybrid
    
  3. Configure the Synchronous Ethernet mapping option, IP address of the timeTransmitter clock as 2.2.2.2, and the interface ge-1/2/3.0 for hybrid mode on the timeReceiver.

    content_copy zoom_out_map
    [edit protocols ptp slave]
    user@host# set interface ge-1/2/3.0 unicast-mode clock-source 2.2.2.2
    

Results

Display the results of the configuration of hybrid mode with the mapping of the PTP clock class to the ESMC quality level:

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[edit protocols ptp slave]
user@host# show
convert-clock-class-to-quality-level
interface  ge-1/2/3.0 unicast-mode clock-source 2.2.2.2 
hybrid

Hybrid Mode with a User-Defined Mapping of the PTP Clock Class to the ESMC Quality-Level

CLI Quick Configuration

To quickly configure hybrid mode on the interface ge-1/2/3.0, copy the following commands, paste them in a text file, remove any line breaks, and then copy and paste the commands into the CLI.

content_copy zoom_out_map
[edit]
set protocols ptp slave hybrid
set protocols ptp slave hybrid
set protocols ptp slave interface unicast-mode ge-1/2/3.0 clock-source 2.2.2.2
set protocols ptp slave clock-class-to-quality-level-mapping quality-level prc clock-class 80

Step-by-Step Procedure

To configure hybrid mode with a user-defined mapping of the PTP clock class to the ESMC quality level on an ACX Series router, perform the following steps:

  1. Configure the quality-level option for the clock-class-to-quality-level-mapping statement on the timeReceiver at the [edit protocols ptp slave] hierarchy level and then configure the clock-class option for the set quality level if you want to manually override the mapping of the ESMC quality level to the clock class.

    content_copy zoom_out_map
    [edit protocols ptp slave]
    user@host# set clock-class-to-quality-level-mapping quality-level prc clock-class 80
    
  2. Configure hybrid mode on the timeReceiver.

    content_copy zoom_out_map
    [edit protocols ptp slave]
    user@host# edit hybrid
    
  3. Configure the IP address of the timeTransmitter clock as 2.2.2.2 , and the interface ge-1/2/3.0 for hybrid mode on the timeReceiver.

    content_copy zoom_out_map
    [edit protocols ptp slave]
    user@host# set  interface ge-1/2/3.0 unicast-mode clock-source 2.2.2.2
    

Results

Display the results of the configuration of hybrid mode with a user-defined mapping of the PTP clock class to the ESMC quality level:

content_copy zoom_out_map
[edit protocols ptp slave]
user@host# show
clock-class-to-quality-level-mapping {
    quality-level prc {
        clock-class 80;
    }
}
interface  ge-1/2/3.0 unicast-mode clock-source 2.2.2.2 
hybrid

Verification

Verify That the Router Is Operating in Hybrid Mode

Purpose

Verify the current mode of operation of the timeReceiver.

Action

In operational mode, enter the run show ptp hybrid command to display the current configuration and current mode of operation of the timeReceiver.

In operational mode, enter the run show ptp hybrid config command to display the PTP source to Synchronous Ethernet interface mappings.

In operational mode, enter the run show ptp hybrid status command to display the current hybrid mode operational status.

Meaning

The output displays the current configuration and current mode of operation of the timeReceiver. For information about the run show ptp hybrid operational command, see show ptp hybrid.

Verify the Quality Level Change on the Transmit Side

Purpose

Verify the quality level change on the transmit side of the router.

Action

In operational mode, enter the run show synchronous-ethernet esmc transmit detail command to display the ESMC transmit interface details.

Meaning

The output displays the ESMC SSM quality level transmitted out of various Ethernet interfaces. For information about the run show synchronous-ethernet esmc transmit detail operational command, see show synchronous-ethernet esmc transmit.

Verify Global Information Parameters After Mapping of the PTP Clock Class to the ESMC Quality-Level in Hybrid Mode

Purpose

Verify the global information parameters after mapping of the PTP clock class to the ESMC quality level in hybrid mode by enabling the convert-clock-class-to-quality-level option.

Action

In operational mode, enter the run show ptp global-information command to display the following output:

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user@host> run show ptp global-information
PTP Global Configuration:
Domain number           : 0
Transport Encapsulation : IPv4
Clock mode              : Ordinary
Priority Level1         : 128
Priority Level2         : 128
Unicast Negotiation     : Disabled
ESMC QL From Clock Class: Enabled
Clock Class/ESMC QL     : 84 / (QL SSU-A/SSM 0x4)
Slave Parameters:
  Sync Interval         : -
  Delay Request Interval: -6 (64 packets per second) 
  Announce Interval     : -
  Announce Timeout      : 3 
Master Parameters: 
  Sync Interval         : -6 (64 packets per second) 
  Delay Request Interval: - 
  Announce Interval     : 1 (1 packet every 2 seconds) 
  Clock Step            : one-step 
Number of Slaves       : 1 
Number of Masters      : 0 

In operational mode, enter the run show ptp quality-level-mapping command to display the following output:

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user@host> run show ptp quality-level-mapping
quality level         ptp clock class
PRC                      84
SSU-A                    92
SSU-B                    96
SEC                      104

Meaning

The output for run show ptp global-information displays the parameters set in Synchronous Ethernet mode and the parameters set for the timeTransmitter and the timeReceiver.

The output of run show ptp quality-level-mapping displays the default mapping of the clock class to the ESMC quality level.

Verify Global Information Parameters After Configuring User-Defined Mapping of the PTP Clock Class to the ESMC Quality-Level in Hybrid Mode

Purpose

Verify the global information parameters after configuring a user-defined mapping of the PTP clock class to the ESMC quality level in hybrid mode by disabling the convert-clock-class-to-quality-level option.

Action

In operational mode, enter the run show ptp global-information command to display the following output:

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user@host> run show ptp global-information
PTP Global Configuration:
Domain number           : 0
Transport Encapsulation : IPv4
Clock mode              : Ordinary
Priority Level1         : 128
Priority Level2         : 128
Unicast Negotiation     : Disabled
ESMC QL From Clock Class: Disabled
Clock Class/ESMC QL     :  -
Slave Parameters:
  Sync Interval         : -
  Delay Request Interval: -6 (64 packets per second)
  Announce Interval     : - 
  Announce Timeout      : 3 
Master Parameters:   
  Sync Interval         : -6 (64 packets per second) 
  Delay Request Interval: -
  Announce Interval     : 1 (1 packet every 2 seconds) 
  Clock Step            : one-step 

Meaning

The output displays the parameters set in Synchronous Ethernet mode and the parameters set for the timeTransmitter and the timeReceiver.

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