| 摘要 |
<p>Security against an unauthorized access in the network, transmission path cut-off, and destruction of a network constituting member such as a node. In a network in which the number of bytes of an ACM (Access Control Message) portion of a frame format corresponds to the number of times date passes through the broad band transmission path, a reception node decides whether to allow data access according to the number of bytes of the ACM portion. In a sub-net evading a data conflict by utilizing a trigger token, the security against physical destruction functions as follows. When a trigger token is received, a data string, a trigger token, or an ACK (acknowledge) signal is returned immediately and a timer for trigger token retransmission is started cooperatively. Thus, a normal node indicates a defective node and a transmission path trouble.</p> |
