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Configuration Guide - Device Management

S7700 and S9700 V200R013C00

This document describes the configurations of Device Management, including device status query, hardware management, CSS, SVF, PoE, OPS, OIDS, energy-saving management, information center, fault management, NTP, synchronous ethernet, PTP.
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Configuring a BITS Clock Source

Configuring a BITS Clock Source


To implement clock synchronization on a switch, configure a clock source first. A BITS clock source refers to the clock signal sent from a BITS interface to a network element. The signal can be a clock signal or a time signal.

When multiple clock sources are available, a switch selects a clock source as its reference clock according to the clock source priority and Synchronization Status Message (SSM) quality level.
  • Clock source priority

    The default priority for a clock source is 255, indicating that this clock source does not participate in clock source selection. To enable the clock source to participate in clock source selection, specify a priority for it.

    A lower priority value indicates a higher priority of a clock source.

  • Clock source SSM quality level

    An SSM is a group of codes used to indicate the clock quality level on a synchronized network. SSM reflects the level of synchronous timing signals transmitted on a synchronous timing link. A higher clock accuracy indicates a higher SSM quality level. A device can be configured to select a clock source according to the SSM quality level.

    SSM quality levels are sorted in descending order of preference: primary reference clock (PRC), Synchronization Supply Unit A (SSU-A), Synchronization Supply Unit B (SSU-B), SDH equipment clock (SEC), and Do Not Use (DNU).

Perform the following operations to configure a BITS clock source:


  1. Run system-view

    The system view is displayed.

  2. Run clock bits-type { bps-2m | hz-2m | bps-1544m } { bits0 | bits1 }

    The BITS clock mode is configured.

    Alternatively, run the clock bits-type { dcls-time | 1pps-tod } { in | out } { bits0 | bits1 } command to configure the BITS time mode.

    By default, BITS clocks adopt the bps-2m mode.

  3. Run clock source source priority priority { system | bits0 | bits1 }

    A priority is configured for the clock source traced by an external clock source.

    By default, the priority of an internal clock source and a system clock source is 254, and the priority of other clock sources is 255. A smaller priority value indicates a higher priority.

    • The priority of a system clock source ranges from 0 to 8.
    • The priority of a BITS clock source ranges from 5 to 9.

  4. Run clock source source ssm { prc | ssua | ssub | sec | dnu }

    An SSM quality level is configured for the clock source.

    By default, the SSM quality level of a clock source is SEC.

Updated: 2019-04-20

Document ID: EDOC1100065738

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