| 摘要 |
<p>Communication relay device and method for relaying IP packets exchanged between a manufacturing device connected to an IP network, a manufacture monitoring/control device connected to the IP network to monitor/control the operation of the manufacturing device, and an operating status monitoring device for monitoring the operating status of the manufacturing device based on information contained in IP packets exchanged between the manufacturing device and the manufacture monitoring/control device. The communication relay device stores IP and MAC addresses assigned beforehand to the manufacturing device and the manufacture monitoring/control device, and sends out ARP packets containing the IP addresses of the manufacturing device and the manufacture monitoring/control device, respectively, and also containing the MAC address of the communication relay device. When an IP packet is received from any one of the devices, the communication relay device stores the sequence number contained in the received IP packet, replaces the sequence number with one that is acceptable to a destination of the IP packet, and forwards IP packet to the destination.</p> |
