| 摘要 |
A plurality of communication lines are connected to a gateway. The gateway relays a communication message between the communication lines. A communication message input to the gateway from a first communication line out of the communication lines is defined as a first communication message. The gateway generates a communication message for relay. The communication message for relay contains first path information and second path information incorporated into the first communication message. The first path information indicates the first communication line. The second path information indicates the fact that the first communication message has been input to the gateway. Further, the gateway transfers the communication message for relay to at least one communication line different from the first communication line. The communication device determines the reliability of the received communication message based on the first path information and the second path information in the received communication message. |
