A service impact event analyzer is used to evaluate service assurance risk in cloud SDN networks. Using data fusion, an alarm subset dataset is generated from a raw trap dataset. Service impact events are identified in the subset dataset. The service impact events are categorized into service impacted event categories, and a model is created for associating the event categories with process function classes. Time durations of the service impact events are computed using correlated secondary alarms from the alarm subset dataset. The service assurance risk is evaluated using the model and the time duration.