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Synchronizing Internal Stratum 3 Clock to External Clock Sources on PTX Series Routers

The PTX Series Packet Transport Routers support an external synchronization interface that can be configured to synchronize the internal Stratum 3 clock to an external source, and then synchronize the chassis interface clock to that source. You can also configure a primary and a secondary clock source.

The following tasks explain how to configure a recovered clock for an FPC and to configure the clock synchronization options:

Configuring a Recovered Clock for an FPC

To configure a recovered clock for an FPC on PTX Series routers:

  1. Go to the [edit chassis fpc slot-number pic pic-number] hierarchy level.
  2. Configure a port from 0 through 47 through which the clock is recovered.

Configuring External Clock Synchronization Options

Note:

Starting with Junos OS Release 15.1F3, you must configure a recovered clock (recovered-clock port port-number) for an interface before configuring clock synchronization options for the same interface.

Use the synchronization statement options to specify a primary and a secondary timing source. To do this, you must configure the following options:

  • Specify the switching mode as revertive when a lower-priority synchronization source is to be switched to a valid, higher-priority synchronization source.

  • Specify the primary external timing source with the primary (fpc-slot-number | gps-0 | gps-1 | bits-a | bits-b) statement.

  • Specify the secondary external timing source with the secondary (fpc-slot-number | gps-0 | gps-1 |bits-a | bits-b) statement.

Note:

For more information about clock synchronization options, see Understanding Clock Synchronization.

To configure the clock synchronization options:

  1. In configuration mode, go to the [edit chassis synchronization] hierarchy level.
  2. Configure the Synchronous Ethernet clock selection mode as auto-select to select the best external clock source or free-run to use the free-running local oscillator as a clock source.
  3. Configure the ESMC transmit parameters on all the interfaces or on selected interfaces.
  4. Configure the hold interval as configuration-change, which is the wait time (from 15 seconds through 60 seconds) after a change in configuration; restart, which is the wait time (from 60 seconds through 180 seconds) after reboot of the router; and switchover, which is the switchover wait time (from 30 seconds through 60 seconds) after clock recovery.
  5. Configure the interface with an available upstream clock source where the clock source is bits-a, bits-b, gps-0, or gps-1. Configure the pulse-per-second-enable statement to enable the pulse per second (PPS) signal to be received on the GPS interface and configure the frequency for the provided reference clock as 5 MHz, 10 MHz, e1, or t1.
  6. Configure the maximum transmit quality level as prc, prs, sec, ssu-a, ssu-b, st2, st3e, stu, or tnc.
  7. Configure the EEC synchronization networking type as option-1 to map to G.813 option 1 (EEC1)or option-2 to map to G.812 type IV clock (EEC1).
  8. Configure the primary synchronization reference source as bits-a, bits-b, gps-0, gps-1, fpc-0, fpc-1, fpc-2, fpc-3, fpc-4, fpc-5, fpc-6, or fpc-7. The selected source is considered to be the best choice among the available sources.
  9. Configure the quality-mode-enable statement to enable Synchronous Ethernet ESMC quality mode.
  10. Configure the secondary synchronization reference source as bits-a, bits-b, gps-0, gps-1, fpc-0, fpc-1, fpc-2, fpc-3, fpc-4, fpc-5, fpc-6, or fpc-7. The selected source is considered to be the best alternative among the available sources.
  11. Configure the quality selection mode for the incoming ESMC packets as configured-quality or received-quality.
  12. Configure the ESMC source as bits-a, bits-b, gps-0, or gps-1. For the configured source, configure the priority statement from 1 through 5; the quality-level statement as prc, prs, sec, ssu-a, ssu-b, st2, st3e, stu, or tnc; the request statement as force-switch or lockout.
  13. Configure the switchover mode as revertive or non-revertive.
Note:

To configure the Synchronous Ethernet clock sources, you must configure network-option option, quality-mode-enable, and source interfaces interface-name priority value quality-level level along with other parameters as needed at the [edit chassis synchronization] hierarchy level.

To configure ESMC transmit interface, you must configure esmc-transmit interface interface-name along with other parameters as needed at the [edit chassis synchronization] hierarchy level.

Release History Table
Release
Description
15.1F3
Starting with Junos OS Release 15.1F3, you must configure a recovered clock (recovered-clock port port-number) for an interface before configuring clock synchronization options for the same interface.