Description of the problem

OSN3500 device reported NE_NOT_LOGIN and NE_COMMU_BREAK on 8/15/2017.

Alarm message.

Name Alarm source Location information Frequency First occurrence time (ST) Last occurrence time (ST) Clear time (ST)

NE_NOT_LOGIN Core 2 Network element core 2 not logged in 3 08/15/2017 09:20:24 08/15/2017 11:47:42 08/15/2017 11:47:53

NE_COMMU_BREAK Core 2 Connection to network element core 2 broken 3 08/15/2017 09:20:24 08/15/2017 11:47:42 08/15/2017 11:47:52

Processing

The network topology is as follows:

1, query the master control errlog did not see the time off the pipe August 15 reset.

2, suspected DCN network problems, using ping command long ping observation for a period of time.

The command is: ping core 2 IP address -t >> D: record.txt; ping the beginning of the record time is August 15, 12:00:20 p.m. (the advantage of this command is that there is a text record after the end of the ping, which is convenient for querying and analyzing)

3, observation for a period of time found that on August 18, 13:41:20 network elements again off the pipe, will ping command using Ctrl + C keys to end, the record time August 18, 15:40:19.

4, analyze the ping test time end for August 18 15:40:19, start time for August 15 12:00:20, a difference of 272399 seconds, according to the ping command 1S record 1 time, found that the 265260th line, just ping timeout records, just for the network element off the pipe time August 18 13:41:20.

5, according to 4, suspected or DCN problem, understand this problem after the opening of the Bureau, due to equipment problems appear in this phenomenon of low overview, it is recommended to deal with the DCN flash problem.

6, the current network to replace the gateway network element to the DCN cable, the problem is solved, and no longer frequently off the pipe.

Root cause

DCN issues cause frequent de-regulation of gateway network elements.

Solution

Troubleshoot the DCN problem, after replacing the network cable from the gateway network element to the DCN.

Recommendations and Summary

This case uses the ping command, the ping process has a text record, it is convenient to analyze the problem. At the same time, the ping characteristic is 1S record once, you can find the time point of ping timeout record.

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