Network system having function of changing route upon failure

An internetwork apparatus which is coupled to a plurality of networks including a first network coupled to a terminal that relays a packet received from one of the plurality of networks to another of the plurality of networks, comprising:

• a plurality of ports which are coupled to the plurality of networks that transmit and receive packets to and from the plurality of networks, respectively, the plurality of ports including a first port coupled to the first network;
• a relay unit which relays a packet received from each of the plurality of ports;
• a storage unit which stores statistical information of packets transmitted from and received by each of the plurality of ports;
• and
• a control unit which, when the control unit receives a request message requesting the statistical information from an arbitrary one of the plurality of networks through a corresponding one of the plurality of ports and the relay, reads the statistical information stored in the storage unit and transmits a response message including the statistical information thus read to the arbitrary one of the plurality of networks, wherein
• in the case where the first port operates as a current port, when the control unit receives, from the arbitrary one of the plurality of networks, a first request message requesting statistical information of packets transmitted to and received from the first network through the first port, the control unit transmits, through the arbitrary one of the plurality of networks to another internetwork apparatus including a standby port coupled to the first network, a second request message requesting the statistical information of packets transmitted to and received from the first network through the standby port, and wherein
• when the control unit receives a first response message including statistical information requested by the second request message from the another internetwork apparatus, the control unit obtains a sum of the statistical information thus read and the statistical information thus received and transmits a second response message including the sum of the statistical information to the arbitrary one of the plurality of networks.

An internetwork apparatus used in a network system which includes at least two internetwork apparatuses respectively coupled to a plurality of networks and wherein one of the at least two internetwork apparatuses operates as a current internetwork apparatus and the other of the at least two internetwork apparatuses operates as a standby internetwork apparatus, the internetwork apparatus comprising:

• a plurality of ports which are coupled to the plurality of networks that transmit and receive packets to and from the plurality of networks, respectively;
• a relay unit which relays a packet received from each of the plurality of ports;
• a storage unit which stores statistical information of packets transmitted from and received by each of the plurality of ports;
• and
• a control unit which, when the control unit receives a request message requesting the statistical information from an arbitrary one of the plurality of networks through a corresponding one of the plurality of ports and the relay, reads the statistical information stored in the storage unit and transmits a response message including the statistical information thus read to the arbitrary one of the plurality of networks, wherein
• in the case where the internetwork apparatuses operates as the current internetwork apparatus, when the control unit receives a first request message requesting statistical information from the arbitrary one of the plurality of networks, the control unit transmits a second request message requesting statistical information stored in the other of the at least two internetwork apparatuses to the other of the at least two internetwork apparatuses operating as the standby internetwork apparatus, and wherein
• when the control unit receives a first response message including statistical information requested by the second request message from the other of the at least two internetwork apparatuses, the control unit obtains a sum of the statistical information thus read and the statistical information thus received and transmits a second response message including the sum of the statistical information to the arbitrary one of the plurality of networks.