Apparatus for providing connection between networks
AssigneeHitachi Kokusai Electric Inc.
InventorSatoshi Maruta
Life of this patent
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Abstract
When an internal terminal (TM1 to TMn) replaced with another terminal due to the breakdown or the model upgrading and the DHCP function allocates a new private address for the MAC address of the terminal after replacement, the newly allocated private address is managed in association with physical ports (PP1 to PPn) in an expansion NAPT table. Then, in this state, when an IP packet is delivered from an external terminal (TM0) on the side of a WAN(2), the transmission destination address of this IP packet is converted to the private address of the internal terminal after conversion in accordance with the expansion NAPT table using the physical ports as a key.
Claims4
An apparatus for providing connection between networks which transmits an IP packet between a first network to which a first node is connected and a second network to which a second node is connected by using a private address and a port number allocated to the first node and a global address allocated to the second node and the apparatus, comprising:
- an address management table for storing the private address and the port number allocated to the first node in association with a number of a physical port of the apparatus which is connected to the first node;
- a reception unit for receiving the IP packet transmitted from the first or the second node;
- a first retrieval unit for retrieving, when the reception unit receives the IP packet transmitted from the second node, the IP packet having a transmission destination global address and a transmission destination port number as transmission destination address information, a physical port number corresponding to the transmission destination port number from the address management table based on the transmission destination port number of the IP packet;
- a second retrieval unit for retrieving, from the address management table, the private address allocated to the first node connected to the physical port based on the physical port number retrieved by the first retrieval unit;
- an overwrite unit for overwriting the retrieved private address and a retrieved transmission destination port number with the transmission destination global address and the transmission destination port number of the IP packet received by the reception unit;
- and
- a transmission unit for transmitting the IP packet overwritten with the transmission destination address information to the first node through the first network.
Dependencies are inferred from the claim text.