Optical network system

A method of switching one or more of a plurality of switching source OSUs of a station-side termination apparatus, in which a switching source OSU which connects an arbitrary subscriber termination apparatus, receives an up signal from the stored subscriber termination apparatus and, transmits a down signal to the stored subscriber termination apparatus,

• a concentration switch which multiplexes the up signals received by the respective switching source OSUs and, outputs the down signal to a storage destination OSU of the subscriber termination apparatus as a transmission destination of the down signal concerned, and
• a controller which controls the storage destination OSU of each of the subscriber termination apparatuses, the OSU switching method comprising:
• an OSU switching procedure in which the controller transmits, to the concentration switch, such a storage destination change instruction that the storage destination OSU of the subscriber termination apparatus is switched, instructs the switching source OSU to stop transmission of a transmission permission message, and, notifies the information of the subscriber termination apparatus to be stored in the switching destination OSU, whereby the concentration switch performs buffering of the down signal to the subscriber termination apparatus have been stored in the switching source OSU, and, the switching destination OSU having received information of the subscriber termination apparatus performs setting of the subscriber termination apparatus to be stored therein;
• and
• a data transmission start procedure in which after the switching destination OSU completes the setting of the subscriber termination apparatus to be stored therein, the controller notifies the concentration switch and the switching destination OSU of completion of switching from the switching source OSU to the switching destination OSU, whereby the concentration switch outputs the buffered down signal to the switching destination OSU, and, the switching destination OSU notifies the subscriber termination apparatus to be stored therein of restart of transmission.

A station-side termination apparatus comprising:

• a switching source OSU which receives an up signal from a subscriber termination apparatus and, transmits an input down signal to the subscriber termination apparatus;
• a switching destination OSU which, instead of any of the switching source OSUs, receives the up signal from the subscriber termination apparatus and, transmits the down signal to the subscriber termination apparatus;
• a concentration switch which multiplexes the up signals received by the switching source OSU and the switching destination OSU and, separates the down signals for each predetermined data to output the down signals to either the switching source OSU or the switching destination OSU;
• and
• a controller which detects a failure of the switching source OSU and controls operation of the switching source OSU, the switching destination OSU, and the concentration switch corresponding to the presence or absence of the failure, wherein
• in such a state that the controller does not detect the failure of the switching source OSU,
• the controller reads the information relating to control, management, or registration of the subscriber termination apparatus of each of the switching source OSUs periodically or at the time of updating the information and accumulates the information,
• the controller monitors the switching source OSU,
• in such a state that the controller detects the failure of the switching source OSU,
• the controller issues, to the concentration switch, such a storage destination change instruction that a storage destination of the down signal is changed from the switching source OSU to the switching destination OSU,
• the concentration switch switches the storage destination of the down signal in accordance with the storage destination change instruction and, accumulates the down signal addressed to the switching destination in a down buffer,
• the controller writes the accumulated information about the failed OSU in the switching destination OSU,
• the switching destination OSU notifies the controller of completion of reflection after completion of setting of the information,
• the controller issues a transmission instruction to the switching destination OSU based on the reflection completion notification,
• the switching destination OSU starts transmission and reception with the subscriber termination apparatus based on the transmission instruction,
• the controller notifies the concentration switch of the completion of switching based on the reflection completion notification,
• the concentration switch transmits the down signal accumulated in the down buffer to the switching destination OSU based on the switching completion notification and then transmits the down signal input to the concentration switch.

A method of switching a plurality of switching source OSUs of a station-side termination apparatus, which includes a at least one of the switching source OSUs that receives an up signal from a subscriber termination apparatus and, transmits an input down signal to the subscriber termination apparatus,

• a switching destination OSU which, instead of any of the switching source OSUs, receives an up signal from the subscriber termination apparatus and, transmits a down signal to the subscriber termination apparatus,
• a concentration switch which multiplexes the up signals received by the switching source OSU and the switching destination OSU and, separates the down signal for each predetermined data to output the down signal to either the switching source OSU or the switching destination OSU,
• a controller which detects a failure of the switching source OSU and controls operation of the switching source OSU, the switching destination OSU, and the concentration switch corresponding to the presence or absence of the failure, wherein
• in such a state that the controller does not detect the failure of the switching source OSU,
• the method comprising, in sequence, a monitoring procedure in which
• a signal is transmitted and received between the switching source OSU and the subscriber termination apparatus,
• the information relating to control, management, and registration of the subscriber termination apparatus possessed by each of the switching source OSUs is read out periodically or at the time of updating the information and accumulated, and,
• the switching source OSU is monitored,
• an OSU switching procedure in which the information about the failed switching source OSU that is accumulated in the monitoring procedure is set to the switching destination OSU, and,
• the concentration switch switches the storage destination of the down signal from the failed switching source OSU to the switching destination OSU and, accumulates the down signal addressed to the switching destination in a down buffer, and
• a data transmission start procedure in which the switching destination OSU starts transmission and reception with the subscriber termination apparatus, and
• the concentration switch transmits the down signal accumulated in the down buffer to the switching destination OSU and then transmits the down signal to be input to the concentration switch.