Patent ID: 8285139

Claim:
A method for managing alarms in a Long Reach Passive Optical Network (LR-PON) system, comprising: obtaining a Passive Optical Network (PON) signal from an Optical Line Terminal (OLT) or an Optical Network Unit (ONU) on one side; checking whether the obtained PON signal fails and notifying the ONU or the OLT on the other side if the PON signal fails; by the ONU or the OLT on the other side, judging and locating the failure according to the received notification and taking a corresponding action; wherein the obtaining of the PON signal from the OLT or the ONU on one side comprises: obtaining the PON downstream optical signal from the OLT; the checking whether the obtained PON signal fails comprises: judging whether Loss of Signal (LOS) occurs in the obtained PON signal; the notifying of the ONU or the OLT on the other side comprises: switching off a transmitting laser in a downstream direction, or sending a set first-type downstream Alarm Indication Signal (AIS) to the ONU; and the judging and locating of the failure by the ONU or the OLT on the other side according to the received notification comprise: determining, by the ONU, that a failure leading to the LOS occurs on a downstream path from an Electrical Relay (E-R) regenerator to the ONU if the notification indicates switching off the transmitting laser in the downstream direction; or determining that a failure leading to the LOS or Loss of Frame (LOF) occurs on a downstream path from the OLT to the E-R regenerator if the notification indicates sending the first-type downstream AIS; obtaining an electrical signal through optical-to-electrical conversion of the PON downstream optical signal from the OLT; performing frame alignment for a data frame in the obtained electrical signal to judge whether the LOF occurs; and, if a result of the judgment is positive, switching off the transmitting laser in the downstream direction; and determining, by the ONU, that the failure leading to the LOS occurs on the downstream path from the E-R regenerator to the ONU, and taking the corresponding action; or if the result of the judgment is positive, sending the set first-type downstream AIS to the ONU; and determining, by the ONU, that the failure leading to the LOS or LOF occurs on the downstream path from the OLT to the E-R regenerator.