Packet relay device

A packet relay device connected to a plurality of networks, comprising:

• a plurality of network interfaces that transmit or receive packets to or from the networks;
• a plurality of ports connected to physical network lines in the network interfaces;
• a packet transfer unit that determines a transfer destination of a packet received via one of the network interfaces on the basis of header information of the packet and transfers the packet to one of the network interfaces;
• and
• a device control unit that stores a program for controlling the packet relay device, the device control unit including:
• a command analysis unit that analyzes a device configuration command;
• an operation control unit that incorporates a command analysis result and determines an appropriate power state on the basis of the state of hardware;
• and
• a hardware control unit that controls power supply to the hardware and detects statistic information and a failure,
• wherein a plurality of link aggregations that make the network interfaces redundant and handle ports of the redundant network interfaces as a single organized virtual line are used,
• the operation control unit determines a port to be placed on standby in the link aggregations, determines whether there is any active port among the ports belonging to the redundant network interfaces, and, if a first network interface of the redundant network interfaces has no active port, places the first network interface on standby,
• the hardware control unit monitors whether a failure has occurred in an active second network interface of the redundant network interfaces and, if a failure is detected, notifies the operation control unit of the failure, and
• the operation control unit activates the standby first network interface and places on standby the failed second network interface or a failed port thereof.