Alarm Correlation: Alarm Details Panel
Like many other items managed by Open Manage Network Manager, Alarms have a Details panel (see Equipment Details, for example). In addition to the items mentioned above, the Alarm Details also have a Correlations panel.
Alarm parent/child correlation lets you correlate one alarm to another so you can conceal the child alarm(s) in standard alarm views. You can also correlate one alarm to block resolution of another. In effect, parent alarms conceal (or block) correlated child alarms. This can confine alarms that appear or resolve to those requiring action only.
The Correlations panel lists the following:
Correlation Details -- The current correlation state of the current alarm. Attributes include: Correlation Date, Correlated By, and Correlation State along with information about the correlated, parent alarm. In addition to manually removing the correlation, you can right-click in this component to navigate to the details of the correlated alarm.
Caused Alarm(s) -- The alarms caused by this alarm. Right-click to add alarms to the table or to remove them.
Blocked Alarm(s) -- The alarms that are currently blocked from resolution by this alarm. Right-click add alarms to the table (and remove them).
When adding a correlated alarm, you can select any alarm that does not already have a parent alarm, then click Done to make it a child alarm.
When you correlate correlating one alarm to another, Open Manage Network Manager understands their correlation state as either Caused By or Blocked By. By default, the correlation state is Top Level Alarm.
Open Manage Network Manager does not support multiple correlation states so one alarm cannot be both Caused By and Blocked By. However, a parent alarm can have both Caused By and Blocked By child alarms. A single alarm can also be both parent and child. Consider, for example, an alarm that causes several other alarms but is Blocked By another alarm. Its parent alarm would appear in the Correlation Details panel too.
Alarms correlated as Caused By clear automatically when the parent alarm clears. Blocked by alarms status as child alarms disappears when their parent alarm clear. This means they become visible again within the alarm view's default filter.
Alarm Processing Effects
An alarm’s correlation state does not affect alarm processing behavior. So if a clearing event enters Open Manage Network Manager, the open alarm clears regardless of its correlation state. Event counts also continue to increase as duplicate events arrive.
By default all alarm filters exclude child alarms. A filter criteria (Include child alarms) can include child alarms, so you can always see all alarms regardless of their correlation state by selecting the Include child alarms attribute within the expanded alarms portlet and setting the search criteria to Is true.
Additional Alarm Attributes
The following attributes reflect the correlation state for an alarm. When another alarm conceals the child alarm (or blocks it), it sets the following too.
• Correlated By: User who created the correlation.
• Correlation Date: Date the correlation was created
• Correlation State: CausedBy or BlockedBy
• Parent Alarm.
• Has Children: Whether the alarm has children