The implementation of efficient failure management relies on the information collected from the network.In transparent optical networks

such information is delivered by the monitoring equipment.Failures in such networks can be located by encoding on the basis of analyzing the performances of the optical and monitoring devices.The failure location algorithm used in this paper can cope with both the ideal scenarios（no false and/or lost alarms）

and nonideal scenarios（having false and/or lost alarms）

thus improving the accuracy of failure location.