Explanation of SONET/SDH TopologicalLink Down

The Optical Transport Manager for WDM can be configured to receive TopologicalLink Down notifications from the Optical Transport Manager for SONET/SDH. When these are received, the Optical Transport Manager for WDM determines if the received notification corresponds to an impact notification it has calculated. If the notifications correspond, the root-cause of the impact notification is marked as the root-cause of the notification that came from the Optical Transport Manager for SONET/SDH, and this information is passed to Service Assurance Manager. In this case, the alarm repository in Service Assurance Manager shows that what appeared to be a problem in SONET/SDH was in fact caused by a root-cause problem in WDM.