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OSN 500 550 580 V100R008C50 Commissioning and Configuration Guide 02

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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Testing Time

Testing Time

Time synchronization is critical to services on a network. To prevent service interruption upon a time synchronization failure, time availability needs to be tested and ensured.

Testing the IEEE 1588v2 Feature

The IEEE 1588v2 feature needs support from three network layers' devices: BITSs, bearer network devices, and wireless base stations, thereby achieving end-to-end time synchronization.

Prerequisites

  • You are an NM user with Administrators rights or higher.
  • Time parameters have been correctly configured on each NE and a protection subnet has been created. For the configuration methods, see Configuration Example in the Feature Description.
Tools, Instruments, and Materials

GPS antenna, external time cable, and Time Server

Test Connection Diagram

Figure 1-32 is a test connection diagram for the IEEE 1588v2 feature.

Figure 1-32  IEEE 1588v2 test connection diagram

Procedure

  1. In the NE Explorer of NE1, choose Configuration > Clock > Physical Layer Clock > Clock Source Priority Tablefrom Function Tree. On the Clock Source Priority Table tab page, ensure that all time source ports are listed.
  2. Choose Clock Synchronization Attribute from Function Tree. Click Query to check whether the actual port status is consistent with the networking diagram.
  3. Connect NE1, NE2, and NE3 respectively to a time tester. Respectively check whether their IEEE 1588v2 time precision difference is within ±30 ns. If not, add compensation. For details, see Testing the Compensation for Fiber Asymmetry Delay.

Testing the Compensation for Fiber Asymmetry Delay

Fiber asymmetry refers to the length inconsistency between an RX fiber and a TX fiber between two NEs. If possible, avoid fiber asymmetry during IEEE 1588v2 deployment planning and later maintenance.

Prerequisites

  • You are an NM user with Administrators rights or higher.
  • Time parameters have been correctly configured on each NE and a protection subnet has been created. For the configuration methods, see Configuration Example in the Feature Description.
Tools, Instruments, and Materials

GPS antenna, and external time cable, and Time Server

Test Connection Diagram

Figure 1-33 is a connection diagram for testing the fiber-asymmetry-delay compensation.

Figure 1-33  Connection diagram for testing the fiber-asymmetry-delay compensation

Procedure

  1. Compensate the slave port.
    1. When locking IEEE 1588v2 time, NE1 outputs the time through an external time port to the time tester. The time tester traces the GPS time and computes the difference between the GPS time and the time received from NE1.

      NOTE:
      On OptiX OSN 550/580, the TOD port on the AUX board functions as the external time port.

    2. Check whether the difference D1 is within ±30 ns. If yes, perform 1.a for another NE. If no, proceed with the next step.
    3. Set the compensation d to D1 for the slave ports on NE1.
    4. Test the difference between the GPS time and the time output by the external time port locking an IEEE 1588v2 source, and record the difference value to D2.
    5. Check whether D2 is within ±20 ns. If yes, perform 1.a for another NE. If no, go to 1.c and compensate again with the compensation value d = D1 + D2. Then, check whether the difference is within ±20 ns again.
  2. Reversely compensate for fiber asymmetry delay.

    Along the IEEE 1588v2 trace path, check whether the compensation value D of the slave and passive ports on NE1 are 0. If yes, compensate for a slave port; if no, perform the following steps.

    1. Log in to NE1 and add a compensation -D (ns) to the master port connecting the slave and passive ports on NE1.

      NOTE:
      The compensation value's sign on NE1 is reverse to that of the compensation value of the slave port on NE2.

    2. If any other NE has no reverse compensation, go to 2.a. If all NEs have reverse compensation, all compensation operations are complete.
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Updated: 2019-01-21

Document ID: EDOC1100020976

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