Method for an enhanced failure localization in an optical data transmission network, wherein the optical data transmission network comprises at least a first router node and a second router node, wherein the optical data transmission network further comprises at least one optical data transmission line connecting the first router node with the second router node providing optical data transmission using a wavelength division multiplex scheme or a dense wavelength division multiplex (DWDM) scheme, wherein the optical data transmission network comprises a multitude of amplifier nodes arranged in series along the optical data transmission line between the first router node and the second router node, wherein the optical data transmission network comprises at least one failure localization module, characterized in that the method comprises the following steps: -- in a first step, at least in case of a failure of the optical data transmission line detected between the first router node and the second router node, first probing request messages are sent in the direction from the first router node to the multitude of amplifier nodes and second probing request messages are sent in the direction from the second router node to the multitude of amplifier nodes, -- in a second step, subsequent to the first step, the first router node receives first probing acknowledgement messages from at least part of the multitude of amplifier nodes and the second router node receives second probing acknowledgement messages from at least part of the multitude of amplifier nodes, -- in a third step, subsequent to the second step, the content of the first and second probing acknowledgement messages received is compared and it is concluded where along the optical data transmission line the failure is located and whether the failure of the optical data transmission line is due to a break of the optical data transmission line or due to a failure of an amplifier node along the optical data transmission line, wherein in case the first router node comprises the at least one failure localization module, the first and/or second probing acknowledgement messages are received by the localization module or wherein in case the second router node comprises a further failure localization module, the first probing acknowledgement messages are received by the failure localization module and the second probing acknowledgement messages are received by the further failure localization module. -- in a first step, at least in case of a failure of the optical data transmission line detected between the first router node and the second router node, first probing request messages are sent in the direction from the first router node to the multitude of amplifier nodes and second probing request messages are sent in the direction from the second router node to the multitude of amplifier nodes, -- in a second step, subsequent to the first step, the first router node receives first probing acknowledgement messages from at least part of the multitude of amplifier nodes and the second router node receives second probing acknowledgement messages from at least part of the multitude of amplifier nodes, -- in a third step, subsequent to the second step, the content of the first and second probing acknowledgement messages received is compared and it is concluded where along the optical data transmission line the failure is located and whether the failure of the optical data transmission line is due to a break of the optical data transmission line or due to a failure of an amplifier node along the optical data transmission line, wherein in case the first router node comprises the at least one failure localization module, the first and/or second probing acknowledgement messages are received by the localization module or wherein in case the second router node comprises a further failure localization module, the first probing acknowledgement messages are received by the failure localization module and the second probing acknowledgement messages are received by the further failure localization module.