Network relay apparatus, gateway redundancy system, program, and redundancy method

A gateway redundancy system, comprising a plurality of network relay apparatus each of which is configured to relay communication between an access network and a relay destination network as a gateway and to store, in a storage unit, an internal status for determining an operation to be performed for the relaying;

• each of the plurality of network relay apparatus being configured to:
• sequentially record into the storage unit, as the internal status, a redundancy status for indicating whether the each of a plurality of network relay apparatus operates as an active system or a standby system for each subscriber terminal or subscriber terminal group, and a subscriber status for indicating a list of used address information for each subscriber terminal;
• notify or advertise a message containing a predetermined status to a notification destination sequentially at a predetermined timing;
• and
• monitor communication that has reached the each of the plurality of network relay apparatus to sequentially record used address information assigned by another network relay apparatus to a subscriber terminal into the storage unit while relaying communication between the access network and the relay destination network.

A redundancy method for a network relay apparatus, the redundancy method comprising:

• sequentially managing, by a network relay apparatus configured to relay communication between an access network and a relay destination network, in a storage unit, a redundancy status for indicating whether the network relay apparatus operates as an active system or a standby system for each subscriber terminal or subscriber terminal group, and a subscriber status for indicating a list of used address information for each subscriber terminal;
• notifying or advertising, by the network relay apparatus, a message containing a predetermined status to a notification destination sequentially at a predetermined timing;
• monitoring, by the network relay apparatus, communication between another network relay apparatus in a redundancy configuration and a subscriber terminal group;
• and
• recording and managing, by the network relay apparatus, in the storage unit, used address information assigned by the another network relay apparatus to a subscriber terminal as a part of the subscriber status.

A computer readable non-transitory recording medium having recorded thereon a program for causing a processor of a network relay apparatus to operate as:

• a logical storage unit configured to record a redundancy status for indicating whether the network relay apparatus operates as an active system or a standby system for each subscriber terminal or subscriber terminal group, and a subscriber status for indicating a list of used address information for each subscriber terminal;
• and
• a management unit configured to:
• monitor communication between another network relay apparatus in a redundancy configuration and a subscriber terminal group;
• record, into a physical storage unit handling the logical storage unit, used address information assigned by the another network relay apparatus to a subscriber terminal as a part of the subscriber status;
• and
• notify or advertise a message containing a predetermined status to a notification destination sequentially at a predetermined timing.

A program for causing a processor of a network relay apparatus to operate as:

• a logical storage unit configured to record a redundancy status for indicating whether the network relay apparatus operates as an active system or a standby system for each subscriber terminal or subscriber terminal group, and a subscriber status for indicating a list of used address information for each subscriber terminal;
• and
• a management unit configured to:
• monitor communication between another network relay apparatus in a redundancy configuration and a subscriber terminal group;
• record, into a physical storage unit handling the logical storage unit, used address information assigned by the another network relay apparatus to a subscriber terminal as a part of the subscriber status;
• and
• notify or advertise a message containing a predetermined status to a notification destination sequentially at a predetermined timing.