An OSN3500 (version 5.21.18.50 ) device with an expansion subrack reports an RTC_FAIL alarm, and the main control board is replaced to handle the situation. After plugging in the new main control during the replacement process, it is found that the service on the expansion subrack is partially interrupted, and the service is resumed after modifying the ID and sending out the network management data to the new main control.

Alarm information

The corresponding services of the access-side network elements that landed on this OSN3500 service report TU_AIS, and the interrupted services are all the services that landed on the OSN3500 expansion subrack, and there is no alarm on the OSN3500 side.

Processing

1, the customer returned to the operation log and business interruption when the dump alarms to analyze, you can be sure that the master control replacement on the network management data download before it has been interrupted.

2. Send the data to R&D for analysis.

3. The analysis results are as follows:

When OSN3500 replaces the master control board for a single master control, if there is configuration information of the expansion subrack on the newly replaced master control board (that is, there is a logical configuration of XCE ), the data about the expansion subrack of the new master control will be actively downloaded to the network element, which will lead to interruption of the service to the expansion subrack.

This feature is available for OSN3500 R6 release and later.

When replacing a master control board with this type of configuration, first synchronize the master and backup data of the master control board by inserting the new master in the spare master slot, and then reverse the master and backup masters before finally replacing them.

Attachment shows the alarm and operation log when the service interruption occurs: the network element ID of the replacement master is 700, and the service interruption starts from Thu Feb 04 22:55:10 2010. You can combine the operation logs to determine the time point of business interruption, that is, before the completion of sending network management data after replacing the master control.

Root cause

Device Characteristics

Recommendations and Summary

When replacing OSN3500 devices with expansion subracks, if the version is R6 or R6 or above and the configuration is single-master control, first plug the new master control into the spare master control slot and then synchronize the master and backup data of the master control board, and then carry out the master and backup master control reversal and then replace it.