Packet transfer apparatus having network address translation circuit which enables high-speed address translation during packet reception processing
First Claim
1. A packet transfer apparatus for transferring packets between first and second networks, comprising:
- an address assignment circuit which assigns a translated network address to a first node belonging to said first network and having a first network address when said packet transfer apparatus transfers a first packet from the first node to a second node belonging to said second network and having a second network address through a connection;
an address management circuit which stores for said connection said translated network address, associated with said first and second network addresses; and
an address translation circuit which is realized by a dedicated hardware circuit, and translates said first network address contained in a second packet into said translated network address by reference to said address management circuit when said packet transfer apparatus transfers the second packet from said first node to said second node through said connection, and translates said translated network address contained in a third packet into the first network address by reference to said address management circuit when said packet transfer apparatus transfers the third packet from said second node to said first node through said connection.
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Accused Products
Abstract
In a packet transfer apparatus for transferring packets between first and second networks, a translated network address is assigned to a first node in the first network and having a first private network address when the first packet from the first node is transferred to a second node in the second network, and said translated network address is stored in an address management circuit associated with said first and second network addresses. Thereafter, address translation for realizing an NAT function is performed on subsequent packets transferred between the first and second nodes, by a dedicated hardware circuit and reference to the address management circuit, while performing processing for receiving the packets.
38 Citations
18 Claims
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1. A packet transfer apparatus for transferring packets between first and second networks, comprising:
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an address assignment circuit which assigns a translated network address to a first node belonging to said first network and having a first network address when said packet transfer apparatus transfers a first packet from the first node to a second node belonging to said second network and having a second network address through a connection;
an address management circuit which stores for said connection said translated network address, associated with said first and second network addresses; and
an address translation circuit which is realized by a dedicated hardware circuit, and translates said first network address contained in a second packet into said translated network address by reference to said address management circuit when said packet transfer apparatus transfers the second packet from said first node to said second node through said connection, and translates said translated network address contained in a third packet into the first network address by reference to said address management circuit when said packet transfer apparatus transfers the third packet from said second node to said first node through said connection. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A communication system comprising:
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a first network;
a second network; and
a packet transfer apparatus for transferring packets between first and second networks;
said packet transfer apparatus comprises, an address assignment circuit which assigns a translated network address to a first node belonging to said first network and having a first network address when said packet transfer apparatus transfers a first packet from the first node to a second node belonging to said second network and having a second network address through a connection, an address management circuit which stores for said connection said translated network address, associated with said first and second network addresses, and an address translation circuit which is realized by a dedicated hardware circuit, and translates said first network address contained in a second packet into said translated network address by reference to said address management circuit when said packet transfer apparatus transfers the second packet from said first node to said second node through said connection, and translates said translated network address contained in a third packet into the first network address by reference to said address management circuit when said packet transfer apparatus transfers the third packet from said second node to said first node through said connection.
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12. A method for transferring packets between first and second networks, comprising the steps of:
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(a) assigning a translated network address to a first node belonging to said first network and having a first network address when said packet transfer apparatus transfers a first packet from the first node to a second node belonging to said second network and having a second network address through a connection;
(b) storing for said connection said translated network address, associated with said first and second network addresses in an address management circuit; and
(c) translating, by a dedicated hardware circuit, said first network address contained in a second packet into said translated network address by reference to said address management circuit when said packet transfer apparatus transfers the second packet from said first node to said second node through said connection; and
translating, by a dedicated hardware circuit, said translated network address contained in a third packet into the first network address by reference to said address management circuit when said packet transfer apparatus transfers the third packet from said second node to said first node through said connection.
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13. A semiconductor device for use in a packet transfer apparatus which transfers packets between first and second networks, comprising:
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an address assignment circuit which assigns a translated network address to a first node belonging to said first network and having a first network address when said packet transfer apparatus transfers a first packet from the first node to a second node belonging to said second network and having a second network address through a connection;
an address management circuit which stores for said connection said translated network address, associated with said first and second network addresses; and
an address translation circuit which is realized by a dedicated hardware circuit, and translates said first network address contained in a second packet into said translated network address by reference to said address management circuit when said packet transfer apparatus transfers the second packet from said first node to said second node through said connection, and translates said translated network address contained in a third packet into the first network address by reference to said address management circuit when said packet transfer apparatus transfers the third packet from said second node to said first node through said connection. - View Dependent Claims (14)
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15. A method for transferring a packet between first and second networks, comprising the steps of:
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(a) receiving each portion of a packet transmitted from a first node and addressed to a second node, where the first node belongs to said first network and has a first network address, and the second node belongs to said second network and has a second network address;
(b) reading in parallel at least one portion of at least one reference information item from an address management circuit while acquiring said each portion of the packet, where each of the at least one reference information item includes a combination of a network address of a node belonging to the first network, a network address of a node belonging to the second network, and a translated network address, and said at least one portion of the at least one reference information item corresponds to said each portion of the packet;
(c) comparing said each portion of said packet with said at least one portion of at least one reference information item in parallel, by a first dedicated hardware circuit, while receiving a portion of said packet subsequent to said each portion of the packet;
(d) determining one of the at least one reference information item which matches with the packet based on a result of the operation in step (c); and
(e) translating the first network address contained in the packet, into the translated network address included in said one of the at least one reference information item, by a second dedicated hardware circuit.
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16. A method for transferring a packet between first and second networks, comprising the steps of:
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(a) receiving each portion of a packet transmitted from a first node and addressed to a second node, where the first node belongs to said first network and has a first network address, and the second node belongs to said second network and has a second network address;
(b) reading in parallel at least one portion of at least one reference information item from an address management circuit while acquiring said each portion of the packet, where each of the at least one reference information item includes a combination of a network address of a node belonging to the first network, a network address of a node belonging to the second network, and a translated network address, and said at least one portion of the at least one reference information item corresponds to said each portion of the packet;
(c) comparing said each portion of said packet with said at least one portion of at least one reference information item in parallel, by a first dedicated hardware circuit, while receiving a portion of said packet subsequent to said each portion of the packet;
(d) determining one of the at least one reference information item which matches with the packet based on a result of the operation in step (c); and
(e) translating the translated network address contained in the packet, into the first network address included in said one of the at least one reference information item, by a second dedicated hardware circuit.
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17. A packet transfer apparatus for transferring a packet between first and second networks, comprising:
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a packet receiving circuit which receives each portion of a packet transmitted from a first node and addressed to a second node, where the first node belongs to said first network and has a first network address, and the second node belongs to said second network and has a second network address;
an address management circuit which stores at least one reference information item, where each of the at least one reference information item includes a combination of a network address of a node belonging to the first network, a network address of a node belonging to the second network, and a translated network address, and said at least one portion of the at least one reference information item corresponds to said each portion of the packet;
a reading control circuit which controls said address management circuit so as to output in parallel at least one portion of at least one reference information item;
a packet data acquisition circuit which acquires said each portion of the packet, and supplies said each portion of the packet to a comparison circuit in synchronization with said at least one portion of at least one reference information item output from the address management circuit;
said comparison circuit which is realized by a first dedicated hardware circuit, and compares said each portion of said packet with said at least one portion of at least one reference information item in parallel, and determines one of the at least one reference information item which matches with the packet; and
an address translation circuit which is realized by a second dedicated hardware circuit, and translates the first network address contained in the packet, into the translated network address included in said one of the at least one reference information item.
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18. A packet transfer apparatus for transferring a packet between first and second networks, comprising:
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a packet receiving circuit which receives each portion of a packet transmitted from a first node and addressed to a second node, where the first node belongs to said first network and has a first network address, and the second node belongs to said second network and has a second network address;
an address management circuit which stores at least one reference information item, where each of the at least one reference information item includes a combination of a network address of a node belonging to the first network, a network address of a node belonging to the second network, and a translated network address, and said at least one portion of the at least one reference information item corresponds to said each portion of the packet;
a reading control circuit which controls said address management circuit so as to output in parallel at least one portion of at least one reference information item;
a packet data acquisition circuit which acquires said each portion of the packet, and supplies said each portion of the packet to a comparison circuit in synchronization with said at least one portion of at least one reference information item output from the address management circuit;
said comparison circuit which is realized by a first dedicated hardware circuit, and compares said each portion of said packet with said at least one portion of at least one reference information item in parallel, and determines one of the at least one reference information item which matches with the packet; and
an address translation circuit which is realized by a second dedicated hardware circuit, and translates the translated network address contained in the packet, into the first network address included in said one of the at least one reference information item.
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Specification