To include with the low order device of the working preliminary change

摘要

PROBLEM TO BE SOLVED: To perform active/standby switching in order not to drop or overlap data.;SOLUTION: In the active/standby switching control system and the switching control method provided with a high-order device 1, a low-order device 2 of a standby system and a single or a plurality of low-order devices 3 of an active system for switching the low-order devices 3 of the active system and the low- order device 2 of the standby system under control from the high-order device, the high-order device 1 is provided with a means for sending a switching instruction of the low-order device 2 of the standby system in response to the occurrence of an active/standby switching factor and a means for receiving a switching response containing a switching timing to the switching instruction from the low-order device 2 of the standby system and for sending this switching timing to the low-order device 3 of the active system to perform active/standby switching, and each of the low-order device 2 of the standby system and the low-order devices 3 of the active system is provided with a switching processing means for performing active/standby switching according to the switching timing.;COPYRIGHT: (C)2003,JPO