摘要 |
A switch device used in a ring network operating based upon a protocol prescribed to prevent a loop from occurring includes: a transmission section that periodically transmits a predetermined control frame defined in the protocol out to a communication line in the ring network; a reception section that receives a control frame from the ring network; and a determination section that determines the occurrence of a loop when source address information in the received control frame is identical to address information on the transmission section and also when the received control frame is a predetermined control frame defined in the protocol.
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