This Recommendation provides the requirements and analysis of common management functions applicable at NMS-EMS interface. The term "common" is used in two different contexts. In the first context, it includes analysis of the requirements that are applicable for fault, performance, configuration and security management functions. The second usage is to analyse the requirements that are independent of the specific technology. An example of the first context is logging events for alarms, performance threshold crossing, and inventory changes to the data of the entities. An example of the second context is the method for collecting and reporting performance measurements independent of the network technologies, such as EPON or SDH-DLC.