Relay device, network system, and network failure detection method

摘要

A relay device comprises: a packet type determining unit that determines: whether a received packet is a monitoring packet, sent by a first communication device that monitors a network connection state, set the first communication device as the sending source, and set a second communication device that is monitored as the sending destination; and whether the received packet is a monitoring response packet sent as the response to the monitoring packet with sending source address and destination address of monitoring packet interchanged; a transfer processing unit that receives the monitoring packet and transfers it to a destination; a monitoring unit that monitors receipt of the monitoring response packet within a specified period; and a failure notification packet sending unit that generates a failure notification packet and sends it to a specified destination, when the monitoring response packet is not received within the specified period.

主权项

1. A relay device for performing relaying of packets with layer 2 or layer 3, the relay device comprising:
a packet type determining circuit configured to determine:
(i) whether the packet received by the relay device is a monitoring packet sent by a first communication device, the monitoring packet including the first communication device as a sending source and a second communication device as a sending destination, the first communication device monitoring a network connection state, the second communication device being monitored; and(ii) whether the packet received by the relay device is a monitoring response packet sent by the second communication device as the response to the monitoring packet when the second communication device receives the monitoring packet, the monitoring response packet being generated by interchanging a sending source address and a destination address of the monitoring packet; a transfer processing circuit configured to receive the monitoring packet and to transfer the received monitoring packet to a destination of the monitoring packet; a monitoring circuit configured to monitor receiving of the monitoring response packet corresponding to the transferred monitoring packet within a specified period; a learning circuit configured to:
learn a specified destination to which a failure notification packet is to be sent, based on at least the sending source address included in the received monitoring packet;record a correlation of the sending source address and the destination address which are included in the monitoring packet for each of a plurality of received monitoring packets; andlearn as the specified destination the sending source address corresponding to the destination address of the monitoring packet for which the corresponding monitoring response packet is not received within the specified period, based on the recorded correlations; and a failure notification packet sending circuit configured to generate the failure notification packet notifying an occurrence of a communication failure and to send the failure notification packet to the specified destination, when the monitoring response packet is not received within the specified period, the failure notification packet including the destination address of the monitoring packet corresponding to the monitoring response packet not received within the specified period.