Certain intrusion detection units and access control units can store events that occur while the units are disconnected from Security Center but still physically running. Occurrence periods indicate when these offline events occurred, and determine what happens with the events after the units reconnect to Security Center.
The occurrence period of an event is shown in the Occurrence period column in reports and in the Monitoring task. Events are treated differently in Security Center, based on whether its source entity is an intrusion detection unit or an access control unit.
The following table lists the different occurrence periods, and how they affect
events:
| Occurrence period | How the event is treated in Security Center |
|---|---|
| Online |
|
| Grace period |
|
|
|
| Offline alarm |
|
|
|
| Offline |
|
|
Reasons why units can be offline
An access control or intrusion detection unit can be offline in Security Center for the following reasons:
- The unit is rebooting.
- The unit’s firmware is being upgraded.
- The connection between the unit and the Access Manager or Intrusion Manager is lost.
- The connection between the Access Manager or the Intrusion Manager and the Directory is lost. When this happens, the role disconnects from its units until the connection with the Directory is re-established.