This causality relationship means that using a given notification's instance and the designated relationship you can find all other candidate instances. If there are active notifications for any of these instances, those notifications will be related to the first notification.
For example, assume the PowerSupply::network:22.214.171.124:PowerSupply-1::Down notification has a corresponding NCI that indicates this notification causes .Card.Down notifications for any Cards this PowerSupply is Underlying. The creation of the notification and the NCI would have NOTIF look for notifications whose instances are Cards and eventName is Down, and which the PowerSupply is Underlying the Card. If any are found, they are related—the PowerSupply.Down notification is set to cause the other notifications.
The above scenario describes one notification causing another. The inverse scenario is also possible where for example, a .Card.Down notification is caused by PowerSupply.Down and the causality is the same instance through the LayeredOver relationship (that is, the Card is LayeredOver the PowerSupply).
Another same instance example is shown in NCI causality relationship occurs on an instance related to a notified instance where an Interface.Down notification on a particular interface causes an Interface.Unresponsive notification for another interface, and the relationship is ConnectedTo. In this example, the Interface.Down notification for the Router-A-Port-1 interface instance causes the Interface.Unresponsive notification for the Router-B-Port-5 interface instance.
When the Interface::Router-A-Port-1::Down notification and the corresponding NCI are created, NOTIF finds the instance (Interface::Router-A-Port-1) and follows the ConnectedTo relationship. This finds the Interface::Router-B-Port-5 instance with the Interface.Unresponsive notification, and the two notifications are related. The Interface::Router-A-Port-1::Down notification causes the Interface::Router-B-Port-5::Unresponsive notification.