A method and apparatus that employ the use of CDRs to effectively monitor and proactively respond to network or service events that impact performance within a network are disclosed. For example, the method receives a plurality of call detail records (CDRs), wherein each of the plurality of call detail records comprises a plurality of fields. The method determines a n-field rule signature from each of the call detail records (CDRs), and analyzes the n-field rule signatures from the plurality of call detail records (CDRs) for detecting at least one network performance problem.