Monitor and troubleshoot
Documents under this category describe tools that can help you monitor, diagnose, and troubleshoot SR Linux software. This section also includes Log Event documentation to help you interpret log messages generated by SR Linux software.
- Event Handler Guide
  This document describes the functionality and configuration for the event handler framework on the Nokia Service Router Linux (SR Linux).
- Log Events Guide
  This document provides guidance for operators to interpret log events for the Nokia Service Router Linux (SR Linux).
- OAM and Diagnostics Guide
- Troubleshooting Toolkit
  This document describes how to use and configure diagnostic tools for the Nokia Service Router Linux (SR Linux).

stp

higherPriorityBridge

Table 1. higherPriorityBridge properties
Property name	Value
Application name	stp
Event name	higherPriorityBridge
Default severity	warning
Message format string	Bridge bridge-id with root bridge $$ has higher priority, for network instance networkinstance-name on interface interface-name
Cause	A customer's device has been configured with a bridge priority equal to zero.
Effect	The interface that the customer's device is connected through will be blocked.

InterfaceActiveProtocolChange

Table 2. InterfaceActiveProtocolChange properties
Property name	Value
Application name	stp
Event name	InterfaceActiveProtocolChange
Default severity	notice
Message format string	NetworkInstance networkinstance-name SubInterface interface-name active protocol changed to stp-oper-protocol-name.
Cause	The spanning tree protocol on this Subinterface changed from RSTP to STP or viceversa.
Effect	None.

NewCistRegionalRootBridge

Table 3. NewCistRegionalRootBridge properties
Property name	Value
Application name	stp
Event name	NewCistRegionalRootBridge
Default severity	notice
Message format string	New regional-name root cist-regionalroot-name elected in network instance networkinstance-name
Cause	A STP selected a new regional root for the CIST
Effect	None

NewMstiRegionalRootBridge

Table 4. NewMstiRegionalRootBridge properties
Property name	Value
Application name	stp
Event name	NewMstiRegionalRootBridge
Default severity	notice
Message format string	New MSTI regional root msti-regionalroot-name elected in net work instance networkinstance-name. Msti-InstanceId: mst-instance-id
Cause	A STP selected a new regional root for the MSTI
Effect	None

newRootBridge

Table 5. newRootBridge properties
Property name	Value
Application name	stp
Event name	newRootBridge
Default severity	warning
Message format string	New root elected for network instance networkinstance-name due to bridge parameter change.
Cause	The previous root bridge has been aged out and new root bridge is elected.
Effect	The new root bridge creates a new spanning tree topology which may denote loss of customer access or redundancy.

newRootInterface

Table 6. newRootInterface properties
Property name	Value
Application name	stp
Event name	newRootInterface
Default severity	warning
Message format string	New root elected for network instance networkinstance-name due to interface interface-name
Cause	The previous root bridge has been aged out and a new root bridge has been elected.
Effect	The new root bridge creates a new spanning tree topology which may denote a loss of customer access or redundancy.

receivedTCN

Table 7. receivedTCN properties
Property name	Value
Application name	stp
Event name	receivedTCN
Default severity	warning
Message format string	TCN received for network instance networkinstance-name on interface interface-name.
Cause	SubInterface has received a TCN from another bridge.
Effect	This bridge will either have its Config bpdu with topology change flag set if it is a root bridge, or it will pass TCN to its root bridge. Eventually the address aging timer for the forwarding database will be made shorter for a short period of time.

StpBpduGuardError

Table 8. StpBpduGuardError properties
Property name	Value
Application name	stp
Event name	StpBpduGuardError
Default severity	warning
Message format string	A Bpdu-guard error is detected for network instance networkinstance-name on subinterface interface-name
Cause	Edge-SubInterface which has bpdu-guard configured received unexpected Stp Bpdu
Effect	Subinterface will become shutdown and traffic will be blocked.

StpRootGuardViolation

Table 9. StpRootGuardViolation properties
Property name	Value
Application name	stp
Event name	StpRootGuardViolation
Default severity	warning
Message format string	A root-guard violation is detected for network instance networkinstance-name on subinterface interface-name
Cause	SubInterface which has root-guard configured is trying to become root (has a better STP priority vector)
Effect	Subinterface will become alternate and traffic will be blocked.

topologyChangeInterfaceMajorState

Table 10. topologyChangeInterfaceMajorState properties
Property name	Value
Application name	stp
Event name	topologyChangeInterfaceMajorState
Default severity	warning
Message format string	Topology change for network-instance networkinstance-name due to subinterface interface-name major state change
Cause	SubInterface has transitioned its state from learning to forwarding or from forwarding to blocking or broken.
Effect	The spanning tree topology has been modified which may denote loss of customer access or redundancy.

topologyChangeInterfaceState

Table 11. topologyChangeInterfaceState properties
Property name	Value
Application name	stp
Event name	topologyChangeInterfaceState
Default severity	warning
Message format string	Topology change for network instance networkinstance-name due to interface interface-name state change.
Cause	SubInterface has transitioned state to blocking or broken from a state other than forwarding. This event complements what is not covered by topologyChangeInterfaceMajorState.
Effect	The spanning tree topology has been modified which may denote loss of customer access or redundancy.

unacknowledgedTCN

Table 12. unacknowledgedTCN properties
Property name	Value
Application name	stp
Event name	unacknowledgedTCN
Default severity	warning
Message format string	TCN sent for networkinstance-name is unacknowledged
Cause	TCN sent towards the root bridge on the root port (Subinterface) has not been acknowledged within allowed time.
Effect	A portion of the spanning tree topology may not have been notified that a topology change has taken place. FDB tables on some devices may take significantly longer to represent the new distribution of layer-2 addresses.

November 6, 2025