| 摘要 |
A node apparatus (10) included in a local area network having duplicated communication paths comprises duplicated subsystems (11, 12). Each of these subsystems monitors its own operation state. The node apparatus further comprises shared memories (17, 18), each memory storing therein operation state monitoring information on the operation state of its own subsystem and continuously enabling the opposite subsystem to store the operation state monitoring information therein. Duplicately arranged switching control sections (15, 16) switch a master operation to the opposite subsystem when a failure occurs in either one of the subsystems. The switching of the master operation can take place even when a failure occurs in one of the switching control sections (15, 16). Power supplies (19, 20) are also duplicated. <IMAGE> |
