Address translation method

• US 20030048804A1
• Filed: 02/04/2002
• Published: 03/13/2003
• Est. Priority Date: 09/11/2001
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Takeda, Yukiko, Inouchi, Hidenori, Takeuchi, Keisuke, Senou, Takamitsu, Hayashi, Masaya
• Granted Patent: US 7,085,270 B2
• Time in Patent Office: Days
• US Class Current: 370/466
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/251 between different IP versions
• CPC Class Codes: H04L 61/2564 for a higher-layer protocol, e.g. for session initiation protocol [SIP]
• CPC Class Codes: H04L 61/45 Network directories; Name-to-address mapping
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/167 Adaptation for transition between two IP versions, e.g. between IPv4 and IPv6 translation of Internet protocol [IP] addresses H04L61/2503
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A translator includes a unit for communication with a DNS-ALG. The DNS-ALG detects a DNS query to a destination terminal, and performs once translation to IPv6. The DNS-ALG translates a destination temporary IPv6 address, in which a real address of IPv4 acquired from a DNS server of the destination terminal is added with a virtual IPv6 prefix, to a destination temporary IPv4. The IPv6-based DNS-ALG cooperates with the translator to permit alleviation of processing load on the DNS-ALG and reduction in capacity of a translation table of large capacity. A technique is disclosed which, with the above construction, can permit mutual connection among a plurality of VPN'"'"'s without exchanging the existing VPN'"'"'s.

Claims

1. A communication network for connecting a plurality of networks conforming to a first protocol by an address translation unit, wherein

the address translation unit includes a function of mutually translating the first protocol and a second protocol inside the address translation unit, information and communication means necessary for communication with a server unit, and a function of cooperating with the server unit to prepare translation information containing a correspondence relation between an address in the first protocol and an address in the second protocol;

the server unit includes translation information necessary for mutual translation of the first and second protocols in the address translation unit, an address conforming to the second protocol in correspondence to the network conforming to the first protocol, and a function of communicating with another server unit or another address of the server unit in order to prepare the translation information; and

in communication from a first network conforming to the first protocol to a second network conforming to the first protocol, the address translation unit refers to the translation information to translate the address conforming to the first protocol to the address conforming to the second protocol, and to further translate the translated address conforming to the second protocol to the address conforming to the first protocol.

2. A communication network according to claim 1, wherein

the address translation unit further includes a function of identifying the plurality of networks conforming to the first protocol, based on information of a layer two;

and

when receiving a communication request, the address translation unit specifies a network conforming to the first protocol, based on the information of the layer two to perform translation from the first protocol to the second protocol.

3. A communication network according to claim 1, wherein

the plurality of networks conforming to the first protocol are connected to a multiplexing unit, the multiplexing unit and the address translation unit are connected through a plurality of circuits;

the multiplexing unit includes a function of identifying a network conforming to the first protocol, based on information of a layer two; and

when receiving a communication request from the network conforming to the first protocol, the multiplexing unit specifies the network conforming to the first protocol based on the information of the layer two to send a communication request to the address translation unit by using a corresponding circuit.

4. A communication network according to claim 1 for use in a communication network in which the plurality of networks conforming to the first protocol are connected to different address translation units, and the address translation unit is connected to a network conforming to the second protocol.

5. An address translation unit for connecting a plurality of networks conforming to a first protocol, comprising:

a function of mutually translating the first protocol to a second protocol inside the address translation unit;

information and communication means necessary for communication with a server unit; and

an address conforming to the second protocol in correspondence to the network conforming to the first protocol, translation information necessary for mutually translating the first and second protocols, and a function of cooperating with another server unit or a server unit having a function of communicating with another address of the server unit for the sake of preparation of translation information in order to prepare translation information containing a correspondence relation between an address in the first protocol and an addresses in the second protocol.

6. An address translation unit according to claim 5 further comprising:

a function of identifying the plurality of networks conforming to the first protocol, based on information of a layer two; and

means for specifying a network conforming to the first protocol, based on the information of the layer two when receiving a communication request, to perform translation from the first protocol to the second protocol.

7. A communication network for connecting a plurality of networks conforming to a first protocol by an address translation unit, wherein

the address translation unit includes a function of mutually translating the first protocol and a second protocol inside the address translation unit, and information and communication means necessary for communicating with a server unit;

the communication network comprises;

an address conforming to the second protocol in correspondence to a network conforming to the first protocol, translation information necessary for mutually translating the first and second protocols, and means for communicating with another server unit or another address of the server unit to prepare the translation information; and

means for requesting the address translation unit to prepare translation information containing a correspondence relation between an address in the first protocol and an address in the second protocol.

8. A communication network according to claim 7 for use in a communication network in which the plurality of networks conforming to the first protocol are connected to different address translation units, and the address translation unit is connected to a network conforming to the second protocol.

9. A server unit in a communication network for connecting a plurality of networks conforming to a first protocol by an address translation unit, wherein

the address translation unit includes a function of mutually translating the first protocol and a second protocol inside the address translation unit, and information and communication means necessary for communication with a server unit;

the server unit comprises;

translation information necessary for mutually translating the first and second protocols;

means for managing a correspondence relation between identification information of a network, which conforms to the first protocol, and an address, which conforms to the second protocol and is assigned to a server unit belonging to the network conforming to the first protocol, and for communicating with another server unit by referring to the correspondence relation when receiving a name-resolution request of the network conforming to the first protocol; and

means for requesting the address translation unit to prepare translation information containing a correspondence relation between an address in the first protocol and an address in the second protocol.

10. A server unit according to claim 9 for use in a communication network in which the plurality of networks conforming to the first protocol are connected to different address translation units, and the address translation unit is connected to the network conforming to the second protocol.

11. An address translation method in a communication network for connecting a plurality of networks conforming to a first protocol by an address translation unit, wherein

the address translation unit includes a function of mutually translating the first protocol and a second protocol inside the address translation unit, information and communication means necessary for communicating with a server unit, and a function of cooperating with the server unit to prepare translation information containing a correspondence relation between an address in the first protocol and an address in the second protocol;

the server unit includes;

translation information necessary for mutually translating the first and second protocols in the address translation unit;

means for communicating with another server unit in order to prepare the translation information when receiving a correspondence relation between identification information of the network, which conforms to the first protocol, and an address which conforms to the second protocol and is assigned to a server unit belonging to the network conforming to the first protocol, and a name-resolution request of the network conforming to the first protocol, by referring to the correspondence relation; and

means for requesting the address translation unit to prepare translation information containing a correspondence relation between an address in the first protocol and an address in the second protocol; and

in communication from a first network conforming to the first protocol to a second network conforming to the first protocol, the address translation unit refers to the translation information to translate the address conforming to the first protocol to the address conforming to the second protocol, and to further translate the translated address conforming to the second protocol to the address conforming to the first protocol.

12. An address translation method according to claim 11 for use in a communication network in which the plurality of networks conforming to the first protocol are connected to different address translation units, and the address translation unit is connected to the network conforming to the second protocol.

13. Information network comprising a first network, a second network communicative with the first network, a third network communicative with the second network, a first address translation unit for connecting the first and second networks, and a second address translation unit for connecting the second and third networks, wherein

the first address translation unit sends a first temporary address in which an address used in the first network is added with a prefix indicative of the first network, to the second address translation unit through the second network;

the second address translation unit translates the first temporary address to a second temporary address which is an address not used in the third network, to send the second temporary address to the third network; and

correspondence information between the first and second temporary addresses is stored.

14. An information network according to claim 13, wherein

the second temporary address sent from the third network is translated to the first temporary address based on the correspondence information;

the prefix is deleted from the first temporary address; and

a resulting address is sent to the first network.

15. An information network according to claim 14, wherein the first network conforms to a first protocol, and the second and third networks conform to a second protocol.

16. A communication apparatus interposed between first and second networks to intervene in communication between the first and second networks, wherein

an original address which is used in the first network and is sent from the first network is received, a first temporary address in which the original address is added with a prefix is formed, and the first temporary address is sent to the second network;

and

the first temporary address sent from the second network is received, the prefix is deleted from the first temporary address to form the original address, and the original address is sent to the first network.

17. A communication apparatus according to claim 16, wherein

a first address sent from the second network is translated to a second address not used in the first network, and the second address is sent to the first network;

relation between the first and second addresses is held as translation information;

the second address sent from the first network is translated to the first address based on the translation information; and

the first address is sent to the second network.