When the Optical Transport Manager diagnoses a problem, it considers the impact of a failure on other network elements or network connections by following certain relationships in the topology. The Optical Transport Manager propagates impacts through the topology along the Underlying and ComposedOf relationships.
Impact analysis performs two functions:
Correlates alarms that are a result of the underlying root cause problem and labels them in the notification as impacts, by setting their Category attribute to Impact.
Creates ServiceUnavailable notifications for circuits where traffic is no longer flowing because of one or more problems along its path.