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synchronization (MX Series)

Syntax

Hierarchy Level

Description

(MX5-T, MX10-T, MX40-T, MX80-T, MX240, MX480, MX960 , and MX10003 routers) Configure Synchronous Ethernet parameters. For configuration details, see Configuring Clock Synchronization Interface on MX Series Routers.

(MX240, MX480, MX960, and MX2020 routers with SCBE or SCBE2) Configure centralized clocking parameters.

  • Starting in Junos 12.2, configure distribution of the selected chassis clock source to downstream network elements through supported line interfaces.

  • Starting in Junos 12.3, configure an external building-integrated timing supply (BITS) timing source. You can also configure the selected chassis clock, or an incoming Synchronous Ethernet or PTP line source for transmission out the external interface.

  • Starting in Junos 16.1 for the MX104 routers, SSM is supported on the BITS interface and can be configured at the [edit chassis synchronization interfaces bits e1-options] hierarchy level.

For configuration details, see Example: Configuring Centralized Clocking on the Enhanced MX Switch Control Board.

Note:

  • Unified ISSU is not supported when clock synchronization is configured for Synchronous Ethernet.

  • The commit operation fails if you configure bits as source, without first configuring bits interface.

Options

clock-mode (auto-select | free-run)—Specify the mode of operation to select the clock source either from a free-run local oscillator or from an external qualified clock. On MX240, MX480, and MX960 routers with enhanced MPCs, the free-run clock is provided by a local oscillator. On other MX Series routers, the free-run clock is provided by the SCB. The default setting is auto-select mode.

hold-interval (configuration-change | restart | switchover) seconds—Specify the chassis synchronization hold interval type and clock selection wait time:

  • configuration-change—Clock select wait time after change in configuration. The range is 15 through 60 seconds.

  • restart— Clock select wait time after reboot. The range is 60 through 180 seconds. The default is 120 seconds.

  • switchover— Switchover wait time after clock recovery. The range is 30 to 60 seconds. The default is 30 seconds.

interfaces (external | (external-0/0 | external-1/0))—Configure the external interface for operating with a connected external device. This interface can be configured as a clock source, which then becomes a candidate for selection as the chassis clock source by the clock source selection algorithm.

  • signal-type (1mhz | 5mhz | 10mhz | 2048khz | e1 | t1)—Specify the external interface signal type:

    1. 1mhz—Set the signal with a clock frequency of 1 MHz.

    2. 5mhz—Set the signal with a clock frequency of 5 MHz.

    3. 10mhz—Set the signal with a clock frequency of 10 MHz.

    4. 2048khz—Set the signal with a clock frequency of 2048 kHz.

    5. e1—Set the signal as an E1-coded 2048 kHz signal on a 120-ohm balanced line.

    6. t1—Set the signal as a T1-coded 1.544 MHz signal on a 100-ohm balanced line.

  • e1-options—Specify the E1 options:

    1. framing (g704 | g704-no-crc4)—Specify the framing format:

      • g704—G.704 framing format for E1 interfaces

      • g704-no-crc4—G.704 framing with no CRC4 for E1 interfaces

    2. line-encoding (ami | hdb3)—Specify the line encoding:

      • ami— Alternate mark inversion (AMI)

      • hdb3—High-d Density bipolar 3 code (HDB3)

    3. sabit number—Specify the San synchronization status bit used for exchanging SSN quality. The value can be 4, 5, 6, 7, or 8. The default is 4.

  • t1-options—Specify the T1 options:

    1. framing (esf | sf)—Specify the framing format:

      • esf—Extended superframe (ESF)

      • sf—Superframe (SF)

    2. line-encoding (ami | b8zs)—Specify the line encoding:

      • ami— Alternate mark inversion (AMI)

      • b8zs—8-bit zero suppression, bipolar with 8-zero substitution (B8ZS)

network-option (option-1 | option-2)—Specify the synchronization networking:

  • option-1— EEC-1 maps to G.813 option 1 clock

  • option-2—EEC-2 maps to G.812 type IV clock

quality-mode-enable—Specify the clock selection, quality level, and priority setting. The quality level parameter for a Synchronous Ethernet interface is optional when quality mode is enabled and the selection mode is set to received-quality. The default quality level for a Synchronous Ethernet interface is based on the value of network-option: option-1 selects SEC and option-2 selects ST3. Table 1 shows whether SSM quality level is supported for a given external interface signal type and framing. The default setting is disabled.

Table 1: SSM-Quality Level Support by Signal Type and Framing

Signal Type

Framing

SSM Quality Level Supported

E1

G.704

yes

E1

G.704 no CRC4

no

T1

ESF

yes

T1

SF

no

2048 KHz

Not applicable

no

selection-mode (configured-quality | received-quality)—Specify whether the clock source selection should use the configured or received ESMC or SSM quality level for a qualifying interface. In both selection modes, the interface qualifies for clock source selection only when the received ESMC or SSM quality level on the interface is equal to or greater than the configured ESMC or SSM quality level for the interface.

Note:

For the selection-mode statement configuration to take effect, you must set the quality-mode-enable statement at the [edit chassis synchronization] hierarchy level.

  1. configured-quality—The clock source selection algorithm uses the ESMC or SSM quality level configured for a qualifying interface.

  2. received-quality—The clock source selection algorithm uses the ESMC or SSM quality level received on the qualifying interface.

source (external-a | external-b | interfaces (interface-name) | external | (external-0/0 | external-1/0))—Specify clock sources.

(SCB only) The timeTransmitter clock source is external-a interface, the secondary clock source is external-b interface. The clock source is chosen using the clock selection process.

(SCBE only) Specify the external interface to select the external clock source.

(SCBE2 only) Specify the external-0/0 interface or external-1/0 interface to select the external clock source.

  • priority number—Specify a priority level from 1 to 5. When not specified, external-a has higher default priority than external-b interface , and external-b interface has higher default priority than other Gigabit Ethernet or 10-Gigabit Ethernet clock sources, which have the lowest default priority. Any priority you configure is higher than any default priority.

  • quality-level (prc | prs |sec | smc | ssu-a | ssu-b | st2 | st3 | st3e | st4 | stu | tnc)—Specify the quality-level option based on the configured network-option. For quality level details, see quality-level.

    Note:

    Starting with Junos OS Release 12.2R1, the quality-level parameter for a Synchronous Ethernet interface is optional when quality mode is enabled and the selection mode is set to received quality. The default quality level for a Synchronous Ethernet interface is SEC for the option-1 network type and ST3 for the option-2 network type.

    Both option I and option II SSM quality levels are supported:

    • For option-1, quality level must be configured for external clocks (external-a or external-b) whether or not quality level is enabled.

    • For option-2, the default quality level for external clocks is QL_STU whether or not quality level is enabled.

    • Quality level is set to DNU for network-option 1 and set to DUS for network-option 2, if quality-level is not configured and no ESMC messages are received.

    • On the selected active source (primary or secondary, whichever is active), even if ESMC transmit is not enabled, a DNU ESMC will be sent out if network-option is 1, and DUS ESMC will be sent out if network-option is 2. This is applicable only for sources of Ethernet interface type to avoid source looping.

  • request force-switch—Force a switch to this source if the source is enabled and not locked out. You can configure only one source to be force-switched.

  • request lockout—You can configure lockout for any source. When configured, this source is not considered by the clock selection process.

The remaining statements are explained separately. See CLI Explorer.

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 10.4.

Statement introduced in Junos OS Release 17.3R1 for MX10003 router.

Options interfaces, output, and source interfaces external introduced in Junos OS Release 12.3.

Related Documentation