Network relay apparatus and inter-network relay method

A network relay apparatus constructed to relay a multicast packet between logically different multiple networks, the network relay apparatus comprising:

• a first management module configured to manage a first network;
• at least one second management module configured to manage a second network;
• and
• an intra-device relay module configured to relay a multicast packet between the first management module and the second management module,
• the first management module having:
• a transmission device information acquisition module configured to acquire transmission device information used for identifying a transmission device in the first network;
• a first communication route establishment module configured to refer to the acquired transmission device information and establish a communication route from the transmission device in the first network to the first management module;
• and
• a transfer module configured to transfer a multicast packet, which is received from the transmission device via the established communication route, to the intra-device relay module,
• the second management module having:
• a multicast packet receiving module configured to receive the multicast packet from the intra-device relay module;
• and
• a multicast packet transmission module configured to send the received multicast packet to a receiving device in the second network, which makes a request for receiving a multicast packet from the first network,
• the intra-device relay module having:
• a relay information storage module configured to store a relay condition for a multicast packet to be relayed from the first management module to the second management module;
• and
• an intra-device transmission module configured to relay the multicast packet from the first management module to the second management module, based on the stored relay condition.