Communication apparatus and communication method

A first communication apparatus placed between a terminal accommodated in a first Layer 2 network connected to the first communication apparatus and a terminal accommodated in a second Layer 2 network at a second communication apparatus, the first communication apparatus being connected to the second communication apparatus on a Layer 3 network, the first communication apparatus comprising:

• a first port connected to a first Layer 3 network;
• a second port connected to a second Layer 3 network;
• a third port connected to the first Layer 2 network;
• a memory storing:
• an association among a virtual tunnel endpoint (VTEP) assigned an individual source IP address, a virtual local area network (VLAN) to which a terminal apparatus accommodated in the first communication apparatus belongs, and a virtual network identifier (VNI),
• associations between individually different VNIs depending on the VLANs with the same VLAN number, and different virtual VTEPs, which are configured for a plurality of Layer 2 networks connected to the different third physical ports,
• a combination of an output destination of the first Layer 3 network, the first port, and a first priority, and a combination of an output destination of the second Layer 3 network, the second port, and a second priority lower than the first priority, for identifying a routing related to a first tunnel route created in a Layer 3 network between a first VTEP in the first communication apparatus and a first VTEP in the second communication apparatus,
• a combination of an output destination of the second Layer 3 network, the second port, and a second priority lower than the first priority,
• a combination of the output destination of the second Layer 3 network, and the second port, for identifying a routing related to a second tunnel route created in a Layer 3 network between a second VTEP in the first communication apparatus and a second VTEP in the second communication apparatus, and
• QoS priority indicating packet transmission priority on the same tunnel route for each VTEP;
• a software processing module configured to monitor a state of the first Layer 3 network in accordance with a routing protocol and switch the combinations of the output destinations of the first tunnel route based on the monitoring result;
• and
• a relay processing module configured to receive a Layer 2 frame transmitted from the terminal apparatus accommodated in the first communication apparatus to a terminal apparatus accommodated in the second communication apparatus, encapsulate the Layer 2 frame in a Layer 3 packet based on the Layer 2 frame and the association among the VLAN, the VNI, and the VTEP, and transmit the encapsulated packet to a tunnel route,
• wherein, upon the state of the first layer 3 network being normal as a result of the monitoring, the relay processing module is further configured to:
• guarantee a communication bandwidth for a communication of a terminal belonging to a VLAN associated with the first VTEP on the first tunnel route, and transmits a packet to the first layer 3 network via the first port,
• share a bandwidth for a communication of a terminal belonging to each VLAN associated with the second VTEP on the second tunnel route, and transmits a packet to the second layer 3 network via the second port,
• upon the state of the first layer 3 network being abnormal as a result of the monitoring, the software processing module is further configured to:
• switch the combinations of the output destinations of the first tunnel route, and
• the relay processing module is further configured to:
• transmit a packet in accordance with QOS priority associated with each VTEP in terms of a communication of a terminal belonging to a VLAN associated with the first and second tunnel routes.