Method and device for forwarding a clock synchronization message

The present invention refers to a method (33) and device (29, ONT, CPE) for forwarding a clock synchronization message (M), the clock synchronisation message (M) comprising a time correction field (corr) describing an residence time of the clock synchronization message (M). In order to allow for accurate clock synchronization even in case of asymmetric delays within a network in a simple and efficient way, it is suggested that the method comprise determining (37) an arrival time (TA) of the message (M); calculating (41) a modified residence time (corr') that is adjusted based on an offset time (O) derived from the arrival time (TA); modifying (45) the clock synchronization message (M) so that the clock synchronization message (M) includes the modified residence time (corr'); and forwarding (47) the modified clock synchronization message (M') comprising the modified residence time (corr').