Hello, everyone!
Today, I'd like to share a case with you.
Product Model: RTN ( it belong to the transmission before, and it is the same with transmission equipment)
Problem Description
Customer feedback that there is one RTN 980 reset every day. Need to check the reason.
The Topo as below:
Problem Analysis
1.Checked errlog, can see board reset frequently:
2.Checked its DCN information. Its route and neighbor number both more than the device threshold.
1)Its route number reach to 1347. Also NE report DCNSIZE_OVER alarm which indicates the DCN subnet is too large.
2)Its neighbor number is more than 20. NE also report DCNLINK_OVER alarm which indicates that the number of links on a DCN exceeds the recommended value. While the DCN OSPF neighbor is more than 10, this alarm will be reported.
3. Besides, there is one link unstable. That causes its DCN route number to frequently flap.
4.In product documentation, there is a note that a large DCN subnet will cause NE to reset.
Root Cause
The NE reset is because below reasons:
（1） Subnet scale is large
（2） The number of neighbors exceeds the specification.
（3） Links are unstable, route flapping occurs
After disable the unstable link DCN and delete the unused neighbor ports. Issue 2) and 3) are solved. Thus NE status is normal.
Solution Description
1.Closed the unused neighbor ports---already done.
2.Close the unstable link DCN or keep it stable to avoid the route flapping.
3.Divide the subnet less than 200.
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Thank you!
