Hello everyone!
Today I share a case that the hardware status light (hardware alarm indicator) is always on, causing the user to make a judgment error.
Problem Description：
The following figure shows the U2000 alarm status and board information. DLAG (Distributed Link Aggregation Group) is configured for in slot 8 port 1 and slot 11 port 1. The test shows that the connection in slot 11 is good. However, when the hardware in slot 8 is faulty, the board in slot 11 does not carry services.
Troubleshooting process:
1. After the check, it is found that the services protected by the DLAG work at the end of port 1 in slot 8.
2. According to the logs, the customer disconnected the optical fiber from slot 8 and kept the optical fiber in slot 11.
In this case, port 1 on the board in slot 8 reports the Loss alarm at 16:45 and ends at 16:46.
3. On 16:46, LDAG successfully switches services back to port 1 in slot 8. The switching function is normal. The switchover alarm is displayed.
4. When the customer performs the protection switching test again, the switching is normal.
5. The fault alarm indicator of the physical board in slot 8 is on because the optical module of the third port is not installed.
After the LSR_NO_FITED alarm is suppressed, the alarm indicator is off.
Root cause :
The fault alarm indicator of the physical board in slot 8 is on because the optical module on port 3 is not installed, which does not affect services on port 1 in slot 8. When the user sees that the fault alarm indicator on the physical board is steady on, the service is mistakenly considered to be in slot 11.
Solution :
Suppress the LSR_NO_FITED alarm indicating that the laser is not installed.
