MSTP/4/MSTPLOG_PROLOOPBACK_DETECTED

Message

MSTP/4/MSTPLOG_PROLOOPBACK_DETECTED: The MSTP process's port has been set to discarding state because of detecting loopback. (ProcessID=[ProcessID], InstanceID=[InstanceID], PortID=[PortID], IfIndex=[IfIndex], PortName=[PortName], PwName=[PwName])

Description

When the port detected loopback, block the port and arise trap.

Parameters

Parameter Name	Parameter Meaning
ProcessID	Indicates the MSTP process ID.
InstanceID	Indicates the instance ID.
PortID	Indicates ID of the port in the MSTP process.
IfIndex	Indicates the interface index.
PortName	Indicates the port name.
PwName	Indicates the PW name.

Possible Causes

The STP port of the equipment detected a loopback.

Procedure

1. Check whether a local loopback is configured on the interface where the alarm is generated.

If a local loopback is configured on the interface where the alarm is generated, go to Step 3.
If no local loopback is configured on the interface where the alarm is generated, go to Step 2.

2. Check whether a loop is formed by a hub and devices, one of which is connected to the interface.

If a loop is formed by a hub and devices, one of which is connected to the interface, go to Step 4.
If no loop is formed by a hub and devices, one of which is connected to the interface, go to Step 5.

3. Delete the local loopback configuration, and check whether the alarm is cleared. If the alarm persists, go to Step 5.

4. Remove the self-loop network cable from the hub and check whether the alarm is cleared. If the alarm persists, go to Step 5.

5. Collect log information and configuration information, and then contact technical support personnel.