| 摘要 |
PROBLEM TO BE SOLVED: To provide an information transmission device using a ring network with the number of users which exceeds the maximum number of VLAN.SOLUTION: An access port control unit 106 and ring port control unit 105 allow or block communication of a ring port and access port so that a plurality of communication routes having priority and the same allocated identifier do not pass the same section. When communication failure occurs at a ring port, a control frame transmission unit 102 transmits a first control signal for blocking communication of an access port in a connection route having low priority, from the other ring port, and transmits a second control signal for instructing to allow communication of the ring port. Receiving the first control signal, the access port control unit 106 blocks communication of an access port connected to an external network having low priority. Receiving the second control signal, the ring port control unit 105 blocks communication of a ring port where the communication failure does not occur. |
