Description of the problem

A customer wants to configure the SSN2PQ1 board in slot 52 of the OSN 3500 expansion subrack as the system clock source, but the network management returns an error code 38709. The content of the error code is "Invalid timing source", which corresponds to "Invalid clock source" in Chinese. The screenshot is as follows:

Processing

1、According to the error code to determine the checksum error point

According to the size of the error code (the error code is less than 6 bits), you can know that it is the error code returned by the main control board.

2、Troubleshoot the main control code to find the error point

According to the error code, check the main control code, and find that the main control has checksum on the clock source slot. When the clock source slot is the slot on the expansion subrack, this error is prompted.

3, combined with the product design, to find the cause of this limitation

a. The XCE board cannot process the clock (8K) sent from the service board, but can only process the clock and frame header sent from the main cross board of the main subframe, and send them to each service board as the system clock and frame header. That is, the XCE single board cannot extract the clock signal from the business single board on the expansion slot and process it.

b. There is only the clock line from the XCS (main subrack crossover veneer) to the XCE in the extended subrack cable, but not the reverse clock line.

The above two design conditions dictate that the cross veneer cannot extract the clock from the extended subrack business veneer and track it, so the master control restricts this scenario.

Root Cause

product design feature, the cross-board cannot extract the clock from the extended subrack service board and track it, so the master control restricts this scenario.

Solution

Do not attempt to configure the service veneer on the expansion subrack into the clock source priority table (system, route 1/2 2M priority table).

Recommendations and Summary

Do not attempt to configure the service veneer on the expansion subrack into the clock source priority table (system, route 1/2 2M priority table).

The related technical information in this chapter and the SDH equipment troubleshooting process are collected and organized by Shenzhen Optical Transmission Network Technology Co.(www.opticaltrans.com), please retain the reproduction! Our company specializes in the sales of Huawei SDH optical transmission equipment,SDH transmission equipment.