Patent ID: 7730305

Claim:
An authentication method for link protection in an Ethernet Passive Optical Network (EPON) including an Optical Line Terminal (OLT) connected to other network systems and a plurality of Optical Network Units (ONUs) located at a subscriber side of the EPON, the method comprising steps of: distributing an authentication key to both the OLT and an ONU in the EPON; generating first and second random values in one of the OLT and the ONU, generating an authentication request frame containing the first and second random values in the one of the OLT and the ONU, and transmitting the authentication request frame from the one of the ONU and OLT to the other thereof; generating a first hash value according to a predetermined function using the first and second random values contained in the authentication request frame in the other of the ONU and OLT, and transmitting an authentication response frame containing the first hash value from the other of the ONU and OLT to the one thereof; and comparing, in the one of the OLT and the ONU, the first hash value contained in the authentication response frame with a second hash value calculated by the one of the OLT and the ONU according to the predetermined function using the first and second random values and an authentication key distributed to the one of the OLT and the ONU, and transmitting an authentication confirmation frame containing an authentication result value indicating a result of the comparison from the one of the OLT and the ONU to the other thereof, wherein the steps performed by the ONU and the OLT are interchangeable.