The present invention relates to the field of network communications. An Optical Line Terminal (OLT) allocates a Pseudo Wire (PW) label of an access segment PW for a port, and establishes a corresponding relationship between the port information and the PW label; and carries the corresponding relationship between the port information and the PW label in a label management message, and sends the label management message to an Optical Network Unit (ONU) so that the ONU updates a forwarding table, in which the label management message adopts an access network management protocol. As a consequence, a problem of supporting Pseudo Wire Emulation Edge-to-Edge (PWE3) on a data plane of an access segment of an access network is solved under the conditions that device complexity of the ONU is not increased and a configuration of the ONU is slightly changed.