RCA and unmanaged status

Use this information to understand how the RCA plug-in handles events from devices that are in unmanaged state, also known as maintenance state.

The method used by the RCA plug-in to handle events from devices that are in unmanaged state is governed by the value set for the HonourManagedStatus in the RCA plug-in configuration file $NCHOME/etc/precision/RCASchema.cfg. This field can take the following values.

  • 1 (default value): instructs the RCA plug-in to honour the managed status of events. All events from unmanaged devices are placed into mojo.events but then ignored in terms of RCA processing.
  • 0: instructs the RCA plug-in to process events from unmanaged devices as normal events.

The RCA plug-in determines whether the device is unmanaged by looking at the NmosManagedStatus field of the event.

Assuming that the RCA plug-in is configured to honour the managed status of events (HonourManagedStatus = 1), then an event from an unmanaged device cannot be root cause and it cannot be suppressed.

If the event has an event state of ReOccurred and earlier occurrences of this same event indicated that the device was previously managed, then the event record in the mojo.events database is updated and will have its NmosCauseType, NmosSerial and SuppressionState reset to 0, in effect instructing the RCA plug-in to now ignore this event. The managed status of reoccurring events can change because of the following: managed Status is a property of an entity; for example, an interface. The managed status of the entity is stored in a field in the entity record. In addition, events raised on an entity also contain a field called NmosManagedStatus that records the managed status of the entity at the time the event was raised. Therefore it is possible for an event to occur when an entity is being managed, but then later on the same event could reoccur when the entity is unmanaged, that is, after the entity has changed state from managed to unmanaged.

The following scenarios explain how the RCA plug-in handles events whose managed status changes on subsequent occurrences.

Event changes from managed to unmanaged

The sequence is as follows:
  1. The initially occurring event (for example, a ping fail event) is processed as normal for RCA, since the event had an NmosManagedStatus of 0, meaning that the entity was managed when the event first occurred.
  2. Then, some time later, the interface entity is set to unmanaged; that is, the ManagedStatus value for the interface becomes 1.
  3. The event on the interface reoccurs.
  4. The reoccurred ping fail event now contains the field value NmosManagedStatus = 1, but the previous occurrence of this event, still in the database mojo.events, had the field value NmosManagedStatus = 0.
  5. The RCA plug-in detects that the value of the field NmosManagedStatus has changed from 0 to 1, for the ReOccurred (or Updated) event.
  6. The RCA plug-in updates the event record in the database mojo.events and then handles the event as if it had been deleted; that is, it reprocesses all the suppressees of the event because this event is no longer allowed to suppress events.

Event changes from unmanaged to managed

The sequence is as follows:
  1. The initially occurring event (for example, a ping fail event) arrives with a NmosManagedStatus of 1 meaning that the entity was unmanaged when the event first occurred.Therefore the event is processed as if it were a deleted event and is not allowed to suppress events.
  2. Then, some time later, the interface entity is set to managed; that is, the ManagedStatus value for the interface becomes 0.
  3. The event on the interface reoccurs.
  4. The reoccurred ping fail event now contains the field value NmosManagedStatus = 0, but the previous occurrence of this event, still in the database mojo.events, had the field value NmosManagedStatus = 1.
  5. The RCA plug-in detects that the the value of the field NmosManagedStatus has changed from 1 to 0, for the ReOccurred (or Updated) event.
  6. The RCA plug-in updates the event record in the database mojo.events and from then on treats the event is as a normal event; this event now allowed to suppress other events.