When an interface enters the forwarding state, an alarm is triggered. 
Reason: Changes occur on the link state and a new link joins the topology.
Advice: Pay attention to the reason of change on the network topology and check if a fault occurs on the backup link.

The SNMP trap that is generated when the bridge is no longer 
the root bridge of the MSTP process Spanning Tree. Another 
switch with higher priority has already been the root bridge.

The SNMP trap that is generated when a root-guard port 
receives a superior message in the MSTP process.

The SNMP trap that is generated when an edged port of 
the BPDU-guard MSTP process receives BPDU packets.

The SNMP trap that is generated when an Alternate-Port 
or Root-Port is aged out in the MSTP process.

When the edged-port receives a BPDU packet, the edged-port attribute will be disabled.
Then the SNMP trap is generated.

The SNMP trap that is generated when an MSTP instance receive TC BPDUs' number 
exceeds the threshold.

The SNMP trap that is generated when an MSTP process receive TC BPDUs' number 
exceeds the threshold.

When the root bridge status of a MSTI in a specified MSTP process changes, an alarm message is generated. 
The changes include:
1 indicates the the local bridge becomes a root bridge.
2 indicates the local bridge stops functioning as the root bridge.

When a port belonging to the MSTP process enters the forwarding state, an alarm message is generated.
Reason: The link status of an MSTP process changes and a new link is added to the network.
Advice: Pay attention to the reason of change on the network topology and check if a fault occurs on the backup link.

When a port belonging to the MSTP process enters the block state, an alarm message is generated. 
Reason: Changes occur on the link state and a link is removed from the network. 
Advice: Pay attention to the reason of change on the network topology and check if a fault occurs on the link.

When a port enters the congestion state, it generates alarms. 
Reason: Changes occur on the link state and the link quits the topology. 
Advice: Pay attention to the reason of change on the network topology and check if a fault occurs on the link.

When the MSTP process stop functioning as a root bridge, an alarm message is generated. 
Cause: The MSTP process can no longer play the role of the root bridge because another MSTP process with a higher priority becomes the root bridge. 
Solution: Reduce the priority of the new root bridge on the specified MSTI if you do not want another MSTP process to function as the root bridge. 
On the contrary, delete the setting of the original root bridge on the specified MSTI if you want the new MSTP process to function as the root bridge.

When a port enabled with the root guard function on the root bridge receives a packet of a higher priority, an alarm message is generated. 
Cause: An MSTP process attempts to compete for the role of the root bridge. 
Solution: Reduce the priorities on the specified MSTI of all MSTP processes on the device.
Alternatively, reconfigure the root guard function for the port.

When a port enabled with the BPDU guard function of the MSTP process receives BPDUs, an alarm message is generated. 
Cause: An edge port enabled with the BPDU guard function receives BPDUs. 
Solution: Manually restart the port because the port is shut down under the attack of BPDUs.

Specify that the root port has not received any BPDU packets for a long time when loop protection is enabled in MSTP process.

Specify that the edge port is invalid because of receiving a BPDU packet.

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

This notification indicates that the number of Up STP-capable interfaces exceeded the upper threshold.

This notification indicates that the number of Up STP-capable interfaces fell below the lower threshold.

This notification indicates that the bridge is no longer the root bridge.

This notification indicates that the bridge is the root bridge.

When a switch loses the role of the root bridge, an alarm message is generated. 
Reason: The status of root bridge cannot be kept because a switch with a higher priority on the network becomes the root bridge. 
Advice: Reduce the priority of the newly joined switch on the specified MSTI.
If you want the new switch to serve as the root bridge, remove the root setting of the specified MSTI on the original root bridge.

This notification indicates that the root bridge role flapped.

This notification indicates that the flapping of the root bridge role resumed.

This notification indicates that the local device proactively detected its STP topology was flapping.

This notification indicates that the STP topology of the local device stopped flapping.

This notification indicates that the local device received many TC BPDUs from neighbors

This notification indicates that loopback of protocol packets is detected on the port.

This notification indicates that loopback of protocol packets is not detected on the port for a long time.

When the port of root bridge protection receives packets with higher priority, it triggers alarm.
Reason: A switch with higher priority and out of the root bridge protection circle attempts to preempt the status of the root bridge.
Advice: Reduce in the specified MSTI the priority of switches that are directly or indirectly connected to the port.
Re-configure the root bridge protection of the port.

When the BPDU guard port receives the BPDU packets, it generates alarms.
Reason: An edge port enabled with the BPDU guard function receives BPDUs. 
Advice: The port receives BPDU packets that are likely to be hostile attack ones.
The port is shut down at this time and needs to be manually restored by NMS administrators.

The SNMP trap that is generated when an Alternate-Port 
or Root-Port is aged out.

When the edged-port receives a BPDU packet, the edged-port attribute will be disabled.
Then the SNMP trap is generated.

The SNMP trap that is generated when a port turns into 
forwarding state from other state in the MSTP process.

The SNMP trap that is generated when a port turns into 
discarding state from forwarding state in the MSTP process.