The SR-OS alarm model is based on RFC 3877, Alarm Management Information Base (MIB), (which evolved from the IETF DISMAN drafts).
Figure 8 illustrates the relationship of log events, alarms and the LEDs.
Log events that are a raising event for a facility alarm configured with a severity of indeterminate or
cleared will result in those alarms not being raised (but clearing events are processed in order to clear alarms regardless of the severity of the clearing event).
Facility Alarms for children objects is not raised for failure of a
parent object. For example, when an MDA fails (or is
shutdown) there is not a set of port alarms raised.
When a parent alarm is cleared, children alarms that are still in occurrence on the node appears in the active alarms list. For example, when a port fails there is a port alarm, but if the MDA is later shutdown the port alarm is cleared (and a card alarm will be active for the MDA). If the MDA comes back into service, and the port is still down, then a port alarm becomes active once again.
Note that a masked alarm is not the same as a
cleared alarm. The cleared alarm queue does not display entries for previously raised alarms that are currently masked. If the masking event goes away, then the previously raised alarms will once again be visible in the active alarm queue.
