| 摘要 |
[Problem] A node, which has received a request message related to periodic data acquisition, voluntarily uses a broadcast communication to periodically perform a data transmission. Therefore, for example, even when a node, which has transmitted the request message, is not operating because of a hardware fault or the like, the data transmission is still performed, with the result that the network band may be wasted. Further, if the periods included in respective request messages are different from each other, the broadcast communication has to be performed in each period, and hence it is difficult to reduce the traffic amount. [Solution] A node, which receives request messages, comprises: a mechanism that performs a data transmission in a period in which the node itself can perform the data transmission; a response transmission period management table for managing request messages from other nodes; and a device life-and-death management table for managing the states of the other nodes. The node further comprises a means that periodically updates the response transmission period management table and device life-and-death management table, thereby ascertaining the states of the other nodes and that, if any node having transmitted a request message is in a halt state, stops the data transmission. The node still further comprises a means for absorbing the difference between a period requested by an application on the node and the period in which the data is transmitted. |
