A method includes: continuously receiving a first upstream data packet and a second upstream data packet that are sent by an upstream node; copying the first upstream data packet, converting, based on an established connection mapping table, a first packet in two packets obtained through copying, sending a first downstream data packet obtained through conversion to a downstream node or a user terminal, and performing control management on a second packet obtained by copying the first upstream data packet; and copying the second upstream data packet, converting, based on the connection mapping table, a first packet in two packets obtained through copying, sending a second downstream data packet obtained through conversion to the downstream node or the user terminal, and performing control management on a second packet obtained by copying the second upstream data packet.