MTP3:Link Alarms

The link alarm (event) notification message is received by the host application when a MTP3 link is reporting an error.

General explanation of the field of event notification link alarm:

  • The Link handle field specifies the handle of the MTP3 link instance

  • The Alarm field indicates an alarm that can be reported at the link level. The following values are allowed:

Link Alarm Description
Up Link activated or restored
Down Link deactivated or failed
MTP2 not available MTP2 link has been removed
Inhibited locally Link inhibited locally (management initiated)
Inhibited remotely Link inhibited remotely (remote node initiated action)
Uninhibited locally Link uninhibited locally (Manager ctrl request)
Uninhibited remotely Link uninhibited by remote end
Inhibited denied Link inhibit request from management denied
Uninhibited denied Link uninhibit request from management denied
Blocked locally Link locally blocked (Manager ctrl request)
Blocked remotely Link remotely blocked (unknown cause)
Unblocked locally Link unblocked (Manager ctrl request)
Unblocked remotely Link unblocked by remote end (unknown cause)
Congested Local link congested
Congestion stopped Local link congestion abated
Emergency Link is in emergency state
Emergency stopped Link is no more in emergency state
Invalid SLC remote end A signaling link test message (SLT/SLA) received with an invalid SLC
Invalid OPC remote end A signaling link test message (SLT/SLA) received with an invalid OPC
SDT data drop Data dropped; the cause will also be set

  • The Cause field specifies the alarm cause according to alarm type. The following values are allowed:

Link Alarm Cause Description
Decode error Decode error
Invalid message length Invalid message length
Link is inactive Link is inactive
Timer T17 expired Timer T17 expired
Invalid OPC Invalid OPC
Remote negatively acknowledged Remote end negatively acknowledged
Unknown Unknown cause
Invalid test pattern Invalid test pattern in SRT/SRA
Uninhibition in progress Uninhibition in progress
No remote acknowledgment No acknowledgment received from remote end
Path unavailable Route to the point code not available
Restoration failed Link restoration failed
T32 expired Timer T32 (SLT Timer) expired
Remote initiation Remote node initiated action
Management initiation Layer manager initiated action
Local route management initiation Route management initiated action
Self-restart Action due to self-restart
Adjacent restart Action due to adjacent restart
Invalid DPC Invalid DPC
Inhibition in progress Inhibition in progress
MTP2 layer disconnected MTP2 layer disconnected
Linkset deactivated Linkset deactivated
DPC unavailable DPC unavailable
Slave synchronization Slave synchronization