Methods of processing record data are presented, together with a Central Management Node for processing record data, and Management Subsystem DataBases for providing a record data set and matching record data. Triggered by service related network fault event, a key table comprising at least one key type is determined, based on a focus target record and related to the network fault event is determined, which key table is used in the step matching the at least one key with record data sets in determined Management Subsystem DataBases. Matched results are merged, whereafter a service performance indicator may be determined, based on which a multi-layer water flow analysis of subsystem specific performance related indicators can be obtained. This analysis may be successfully used to reveal the location of the service related network fault.