Method and device for forwarding packet in data-over-cable service interface specification system

A method and device for forwarding a packet in a data-over-cable service interface specification system. The method comprises: downloading a configuration file corresponding to a file name from a TFTP server corresponding to an address of the TFTP server, the configuration file carrying an uplink stream parameter, a downlink stream parameter and a virtual private network (VPN) identifier; according to the uplink stream parameter, the downlink stream parameter and the VPN identifier, establishing a bidirectional service stream carrying the VPN identifier; and receiving, from a CM, a DOCSIC protocol-based data packet, adding a virtual local area network (VLAN) identifier corresponding to the VPN identifier into the data packet, and encapsulating the data packet in which the VLAN identifier is added into an Ethernet packet and then forwarding same to a network side via the bidirectional service stream, so that VPN identifier supporting is conducted in the bidirectional service stream according to the VPN identifier of a DOCSIS unidirectional service stream.