Cause 1: The network topology changed because a new link was added into the network topology.
Cause 2: The network topology changed because interfaces went Up or Down.
Cause 3: A fault occurred on the network.
1. Check whether the added physical link is necessary.
2. Run the display erps ringId verbose command to check whether the interfaces are consistent with the STP calculation results.
3. Collect log information and configuration information, and then contact technical support personnel.
1. Run the undo shutdown command in the interface view to check whether the alarm is cleared. If the alarm persists, go to Step 2.
2. Collect log information and configuration information, and then contact technical support personnel.
1. Rectify the fault in the original network topology. If the fault persists, go to Step 2.
2. CCollect log information and configuration information, and then contact technical support personnel.