A method for removing static differential delays resulting from an independent transport of the client signals of a client signal bundle through an optical transport network, OTN, which comprises OTN mappers mapping received client signals to ODU signals transported to OTN demappers demapping received ODU signals to client signals, wherein a process slave, PS, at the OTN mapper end of said OTN network supplies continuously or in response to a received request information about timing relations between the client signals of said client signal bundle to a process master, PM, at the OTN demapper end of said OTN network used by the process master, PM, to remove the static differential delays between the client signals of the respective client signal bundle.