Patent ID: 9083554
Filing Date: 2015-07-14
Classification: H04L

Abstract:
1. An apparatus for providing connection between networks which transmits IP packets between a first network to which a plurality of first nodes are connected and a second network to which a second node is connected by using private addresses and first port numbers allocated to the first nodes and a global address allocated to the second node, the apparatus comprising: an address management table storing entries presenting correspondence relationships between pairs of the private addresses and the first port numbers allocated to the first nodes, virtual port numbers used with a first global address allocated to a WAN (wide area network) port of the apparatus, and physical port numbers of physical ports of the apparatus, each of the first nodes being solely connected to one of the physical ports; a reception unit configured to receive the IP packets transmitted from the first or the second node; a first retrieval unit configured to retrieve, when the reception unit receives a first IP packet transmitted from the second node, the first IP packet having a first destination global address and a first destination port number as transmission destination address information, an entry having a virtual port number identical to the first destination port number from the address management table based on the first destination port number of the first IP packet; a second retrieval unit configured to retrieve, from the address management table, a private address and a first port number allocated to a first node connected to a physical port of which a physical port number is included in the entry retrieved by the first retrieval unit; an overwrite unit configured to overwrite the first destination global address and the first destination port number of the first IP packet received by the reception unit with the retrieved private address and the first port number; and a transmission unit for transmitting the first IP packet overwritten with the retrieved private address and the first port number to the first node through the first network.