request can be carried in the epon oam protocol layer in gpon after the onu passes through the ranging phase the olt allocates an onu id to the onu the onu may send a user authentication request message to the olt by using an operation management control interface omci or physical layer oam ploam message block 130 after receiving the authentication request message sent by the onu the olt makes a search and comparison in an internal authentication information database according to the password id and determines whether the password id is matched if it is matched and in normal authorized mode it proceeds to block 140 if it is unmatched or in unauthorized mode it proceeds to block 150 block 140 the olt opens the channel from the onu to the network side and returns an authentication result message to the onu then performs the subsequent operations such as onu configuration restoration block 150 when the password id is unmatched or in unauthorized mode the olt closes the channel from the onu to the uplink network side or keeps the channel in closed state and returns a message carrying authentication failure information to the onu block 160 after receiving the authentication result message the onu determines whether the authentication succeeds marks the authentication state succeeded or failed internally and determines the message processing mode according to the authentication state if the authentication succeeds it proceeds to block 170 if the authentication is failed it proceeds to block 180 block 170 the onu forwards service traffic transparently between the pon port and user ports block 180 the onu captures the user data packets to a cpu inside the onu prompts the user to input the password id and.