| 摘要 |
<p>From a time point of last confirmation of operation of the working device 51 until a time point of next confirmation, the standby device 52 receives the same packet as that whose transfer processing is executed by the working device from the interface units 521-1 ~521-n, processes the packet by the transfer unit 522 and holds the processed packet in the accumulation units 525-1 ~ 525-n. The device monitors an operation state of the working device 51 by an advertisement transmitted by the working device 51 and upon reception of the advertisement, responsively abandons the packet held in the accumulation units 525-1 ~ 525-n. When determining that the working device 51 stops by non-arrival of an advertisement for a predetermined time period, the device sends out the packet held in the accumulation units 525-1 ~ 525-n and switches processing so as to itself operate as a working device.</p> |
