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An MSP ring consisting of five OSN3500s from A-B-C-D-E-A, a bureau has service interruption between B-C due to fiber breakage occurring on the ring, and the service is restored after the fiber cable is restored.
Alarm messagesAPS_INDI, HP_UNEQ
Processing1. Query the K-byte information of the 2 points of inversion on the ring, and find that there is no abnormality;
2. Network management query the information of the ring network of the multiplexing section, and find that point C reports that "the protection state query fails", and query the information with the command line.
:cfg-get-rmsstate:1
Return: failed! 0x9760 NSERR_BDRSP_BAD_PARA; it is suspected that the C-point multiplexing segment information is lost.
3, consult the user, it has done the following operations at point C: point C can not be configured for business, the bureau suspected that the GSCC failure, so replace it with a new GSCC, download data prompted by the download failure! The original GSCC inserted to restore the original, but did not download.
As the master and single-board communication under the configuration is realized through the AUX single board, then try to replace the AUX single board, can not configure the problem of business solutions.
4, therefore, suspect that the failure of the old master control back to plug, due to the failure of the AUX single board at that time, not all synchronization led to the loss of cross-side multiplexing segment node information, and subsequently did not download and verify the result. Configure the multiplexing segment parameters at point C, invert the test, the problem is solved.
5. Since the calibration is done after the network management data is sent down to the GSCC, the multiplexing segment configuration is available on the host. The data on the cross-board is lost due to abnormal inter-board communication multiplexing segment configuration. The existing inspection cases only query the host-side multiplexing segment configuration,
but the multiplexing segment protocol of NGSDH products is moved down to the cross-board, and it is only purely to check whether the multiplexing segment is configured on the host or not, and it can't thoroughly inspect the hidden network problems. Therefore, this problem cannot be found during the inspection.
Root Cause
The loss of multiplexed segment information on the crossover board at site C causes the failure. That is, although the K-byte pass-through of site C to the dual optical board enables the protocol to be processed normally before inversion, the intermediate pass-through site C is unable to process the K-byte due to the lack of multiplexing segment configuration.
As a result, this site is unable to enter the pass-through state, resulting in the inability of the last 8 vc4s to establish a pass-through, and so the service is interrupted when the service is inverted to the last 8 protection vc4s. Analyzing the black box of the crossover board, we can conclude that the failure of the multiplexing segment module in the crossover board leads to theloss of the
multiplexing segment configuration. Since it was not a hardware failure, it did not trigger the master-standby inversion.
Recommendations and Summary
1. It is recommended that the inspection tool add the multiplexing segment configuration query command of the cross-board to the inspection cases;
2. Periodically query the multiplexing segment information on the network management protection view, or periodically urge the customer to perform the inversion test;.
