| 摘要 |
PROBLEM TO BE SOLVED: To switch a communication path of a user frame at high speed while preventing a loop configuration.SOLUTION: A network control system 1 which controls communication in a multi-ring network in which first and second rings are coupled at a shared link part 401 comprises: a first monitoring device 11 for monitoring a communication state on the basis of reception states of first monitoring frames 311, 312; and a second monitoring device 12 for monitoring the communication state on the basis of reception states of second monitoring frames 321, 322 and third monitoring frames 323, 324. In this network control system 1, if after double failures had occurred at the shared link part 401 and a part other than the shared link part 401, one or both of the double failures were repaired, the second monitoring device 12 recognizes ring recovery earlier than the first monitoring device 11 does. |
