JPH1155319A - Ipv4-ipv6 communication method and conversion device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain communication between the IPv4 and IPv6 terminals without allocating previously nor fixedly an IPv4 address to the IPv6 terminal by performing processing of an IPv4-IPv6 conversion device between the IPv4 terminal, a DNSv4 server device, a DHCPv4 server device, the IPv6 terminal and a DNSv6 server device respectively. SOLUTION: An IP transmitting/receiving means 10 performs transmission/ reception of IPv4 and IPv6 packets between the IPv4 and IPv6 networks. An IP header conversion means 11 converts the IPv4 and IPv6 packets into the IP headers. A DNS substitute means 13 acquires the domain information from a DNS server included in the IPv4 or IPv6 network. An IPv4 address acquisition means 14 acquires an IPv4 address from a DHCP server included in the IPv4 network. Then an IP address conversion information holding means 15 performs conversion between the IPv4 and IPv6 addresses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an IPv4-IPv4
6 communication method and IPv4-IPv6 conversion device,
In particular, IPv4 (Internet Proto
IPv4 terminal using col version 4) and IPv6 (Internet Protocol version 6) as communication protocol
The present invention relates to a method and an apparatus for realizing communication between IPv6 terminals that use IPv6.

[0002]

2. Description of the Related Art As a method of realizing communication between an IPv4 terminal and an IPv6 terminal, an IETF (Internet Enginee
RFC (Request F) issued by ring Task Force
or Comments) “IPv4-mapped IPv4” described in 1884
6 address "and" IPv4-compatible IPv6 address "
Is conceivable.

The above “IPv4-mapped IPv6 address”
Is 127th of 128 bits of the IPv6 address.
Bits 0 to 48 are set to “0”, bits 47 to 32 are set to “1”, and bits 31 to 32 are set to “1”.
IPv4 which sets "IPv4 address" to the 0th bit
6 addresses.

[0004] The "IPv4-compatible IPv6 address" is one of 128 bits of the IPv6 address.
This is an IPv6 address in which “0” is set in the 127th to 32nd bits and “IPv4 address” is set in the 31st to 0th bits.

[0005] When performing communication between an IPv4 terminal and an IPv6 terminal, an IPv4 address is fixedly assigned in advance to an IPv6 terminal communicating with the IPv4 terminal. Also, I
In the course of the communication between the Pv4 terminal and the IPv6 terminal, I
Convert P header to IPv4 packet (RFC791)
There is provided a packet conversion device for performing mutual conversion between IPv6 and IPv6 packets (RFC1883).

In an IPv4 network, communication is performed using an IPv4 packet by using an IPv4 address of an IPv4 terminal and an IPv4 address assigned to the IPv6 terminal. In an IPv6 network, I
The above “IPv4-mappedI” in which “IPv4 address of IPv4 terminal” is set as the IPv6 address of the Pv4 terminal
The "IPv4-compatii" in which "Pv6 address" is used and "IPv4 address assigned to IPv6 terminal" is set as the IP address of the IPv6 terminal.
bleIPv6 address, and communicate using IPv6 packets. Then, the packet conversion device includes I
The “IPv4-mappe” included in the Pv6 packet
d IPv6 address ”is converted to“ IPv4 address of IPv4 terminal ”, and the“ IPv4-compatible IPv6 address ”is converted to“ IPv4 address assigned to IPv6 terminal ”.
By converting the IPv6 packet into an “4 address”, the IPv6 packet is converted into an IPv4 packet.

On the contrary, the “IPv4 address of the IPv4 terminal” included in the IPv4 packet is changed to the “IPv4-map”.
ped IPv6 address "and convert the" IPv4 address assigned to the IPv6 terminal "to the" IPv4-com
patible IPv6 address ".
Converts Pv4 packets to IPv6 packets. This enables communication between the IPv4 terminal and the IPv6 terminal.

[0008] In IETF, an IPv4 terminal and an IP4
As a method of realizing communication between v6 terminals, a method called a dual stack is also proposed. According to this method, the IPv6 terminal implements both the IPv4 and IPv6 communication protocols, and the IPv6 terminal communicates between the IPv6 terminals.
Communication is performed using the IPv6 protocol, and communication with the IPv4 terminal is performed using the IPv4 protocol. This allows I
Communication between the Pv4 terminal and the IPv6 terminal becomes possible.

The IETF has also proposed a method called IP tunneling. This is a method of encapsulating with an IPv4 header and passing through the IPv4 network when an IPv4 network exists on a communication path between two IPv6 terminals and communication cannot be directly performed by an IPv6 packet. Similarly, when there is an IPv6 network on a communication path between IPv4 terminals and it is not possible to communicate directly with an IPv4 packet, this is a method of encapsulating with an IPv6 header and passing through the IPv6 network. This enables communication between IPv6 terminals even when there is an IPv4 network on the communication path. Similarly, communication between IPv4 terminals becomes possible even when there is an IPv6 network on the communication path.

[0010]

In the above method, the IP
Communication between an IPv4 terminal and an IPv6 terminal can be realized by a simple operation of adding a 96-bit fixed pattern to a v4 address or deleting a 96-bit fixed pattern from an IPv6 address.

In a method called a dual stack,
Communication between the IPv4 terminal and the IPv6 terminal can be realized by using the communication protocol of the IPv4 and the IPv6 depending on the communication partner.

In a method called IP tunneling,
By encapsulating and passing the network on the communication path of the two terminals with the header of the communication protocol, communication between the two terminals can be realized.

However, the above technique has the following problems.

A first problem is that an IPv4 address must be fixedly assigned to all IPv6 terminals that may communicate with the IPv4 terminal. This will further consume depleted IPv4 addresses and accelerate depletion.

The second problem is that since the IPv4 network and the IPv6 network cannot refer to each other's domain information (for example, an IP address corresponding to a domain name), the actual IP address is used instead of the domain name. That is, you can only specify a partner.

This means that the other party must be aware of whether the other party is using IPv4 or IPv6 as a communication protocol.

The third problem is that, in a method called a dual stack, the IPv4 protocol is implemented on all IPv6 terminals that may communicate with the IPv4 terminal,
This means that the v4 address must be fixedly assigned. This requires a larger memory capacity than implementing only the IPv6 protocol, and accelerates the depletion by further consuming the depleted IPv4 addresses, as in the first problem.

A fourth problem is that, in a method called IP tunneling, in order to allow an IPv4 network existing on a communication path between two IPv6 terminals to pass through encapsulation of an IPv4 header, a setting for that is set in advance. That is what you have to do. Similarly, an I2 existing on a communication path between two IPv4 terminals
In order to pass a Pv6 network through encapsulation of an IPv6 header, it is necessary to make settings for that in advance. This can only be used while IP tunneling is set in advance,
Communication cannot be performed while settings have not been made in advance.

Therefore, an object of the present invention is to implement only the IPv6 protocol in an IPv6 terminal, perform communication between the IPv4 terminal and the IPv6 terminal without previously fixedly assigning an IPv4 address, and perform a domain instead of an IP address. It is an object of the present invention to provide a method and an apparatus for enabling communication between an IPv4 terminal and an IPv6 terminal by specifying a partner by a name.

It is another object of the present invention to provide a method and an apparatus for enabling communication between two IPv6 terminals separated by an IPv4 network without performing special settings in advance. Similarly, it is another object of the present invention to provide a method and apparatus for enabling communication between two IPv4 terminals separated by an IPv6 network without performing special settings in advance.

[0021]

According to a first aspect, the present invention provides a communication network system comprising an IPv4 network, an IPv6 network, and an IPv4-IPv6 translator connected to both of them.
A method for communicating between an IPv4 terminal of an IPv4 network and an IPv6 terminal of an IPv6 network, comprising:
When the IPv4 terminal of the IPv4 network queries the IPv4-IPv6 translator for the IP address for the domain name of the IPv6 terminal of the IPv6 network, the IPv4-IPv6 translator translates the DNS (Dmain Name) that manages the domain information of the IPv6 network.
System) DHCP (Dynamic Host Configura) that acquires an IPv6 address for the domain name from a v6 server device and dynamically allocates an IPv4 address.
Action Protocol) dynamically obtains an IPv4 address corresponding to the IPv6 address from a v4 server device,
Notify the Pv4 terminal that the IPv4 terminal has its own IP
An IPv4 packet is created with the v4 address as the IPv4 source address and the notified IPv4 address as the IPv4 destination address, and sent to the IPv4-IPv6 translation device. (b) The IPv4-IPv6 translation device sends the received IPv4 packet to the received IPv4 packet. The fixed data is added to the IPv4 source address included in the IPv4 packet to convert the address into an IPv6 source address, and the IP address included in the IPv4 packet is changed.
An IPv6 packet is created from the IPv4 packet by an IP header conversion that converts the Pv4 destination address to an IPv6 destination address using the corresponding IPv6 address, and is sent to an IPv6 network. (C) The IPv6 terminal has its own IPv6 address. Is created as an IPv6 source address and an IPv6 source address included in the received IPv6 packet is used as an IPv6 destination address, and sent to the IPv4-IPv6 translator, and (d) the IPv4-IPv6 translator receives the IPv6 packet. The fixed data is deleted from the IPv6 destination address included in the packet and converted to an IPv4 destination address, and the IPv6 source address included in the IPv6 packet is converted to an IPv4 address using the corresponding IPv4 address. Create an IPv4 packet from the IPv6 packet by the IP header conversion for converting the signal address, it provides IPv4-IPv6 communication method characterized by delivering the IPv4 network.

IPv4-IPv6 according to the first aspect
According to the communication method, communication from an IPv4 terminal of an IPv4 network to an IPv6 terminal of an IPv6 network can be started.
To dynamically assign IPv4 addresses to v6 terminals,
It is not necessary to fixedly assign an IPv4 address to an IPv6 terminal in advance, and it is possible to suppress consumption of a depleted IPv4 address. In addition, IPv4-IPv6
If the translator is the IP to the domain name of the IPv6 terminal
In order to automatically obtain the address from the DNSv6 server device, the IPv4 terminal specifies the domain name and
Communication with 6 terminals is enabled.

It is to be noted that the IPv4-IPv6 conversion device is an
The processes performed between the v4 terminal, the DNSv4 server device, the DHCPv4 server device, the IPv6 terminal and the DNSv6 server device are all standard technologies described in RFC, and it is not necessary to add a new modification to the device.

According to a second aspect, the present invention relates to a communication network system comprising an IPv4 network, an IPv6 network, and an IPv4-IPv6 translator connected to both of them, and an IPv4 terminal of an IPv4 network and an IPv6 terminal of an IPv6 network. A method for communicating with a terminal, wherein (a) an IPv6 terminal of an IPv6 network assigns an IP address to a domain name of an IPv4 terminal of the IPv4 network to the IPv4 network.
-When the IPv6 translator is contacted, the IPv4-I
The Pv6 translation device obtains an IPv4 address for the domain name from a DNSv4 server device that manages domain information of the IPv4 network, and obtains the IPv4 address for the domain name.
The fixed address is added to the address to convert it to an IPv6 address, and the IPv6 address is notified to the IPv6 terminal.
The terminal sets its own IPv6 address as the IPv6 source address and sets the notified IPv6 address as the IPv6 address.
Create an IPv6 packet as a destination address, and
The packet is sent to the Pv4-IPv6 conversion device, and (b) IPv4-
The IPv6 translator removes the fixed data from the IPv6 destination address contained in the received IPv6 packet and
The IPv4 address corresponding to the IPv6 source address included in the IPv6 packet is dynamically acquired from a DHCPv4 server device which converts the IPv4 address to a Pv4 destination address and dynamically allocates the IPv4 address, and obtains the IP address.
The IP address is converted from the IPv6 packet to an IP address by an IP header conversion that converts the IPv4 address to an IPv4 source address.
(c) The IPv4 terminal creates an IPv4 packet using its own IPv4 address as an IPv4 source address and an IPv4 source address included in the received IPv4 packet as an IPv4 destination address. , The IPv4
(D) IPv4-IP to be sent to the 4-IPv6 conversion device
The v6 translator adds the fixed data to the IPv4 source address included in the received IPv4 packet and
The source address is converted to an IPv4 destination address, and an IPv4 destination address included in the IPv4 packet is converted to an IP address corresponding to the IPv4 destination address.
The IPv4 packet is converted to an IPv6 destination address by using an IPv6 address.
An IPv4-IPv6 communication method is characterized in that a v6 packet is created and transmitted to an IPv6 network.

IPv4-IPv6 according to the second aspect
According to the communication method, communication with an IPv6 terminal of an IPv6 network can be started from an IPv6 terminal of the IPv6 network.
To dynamically assign IPv4 addresses to v6 terminals,
It is not necessary to fixedly assign an IPv4 address to an IPv6 terminal in advance, and it is possible to suppress consumption of a depleted IPv4 address. In addition, IPv4-IPv6
The translating device determines that the I to the domain name of the IPv4 terminal
To automatically obtain the P address from the DNSv4 server device, the IPv6 terminal specifies the domain name and
Communication with four terminals is possible.

In a third aspect, the present invention provides (a) an IPv6
The IPv4 address corresponding to the IPv6 address of the IPv6 terminal of the 6 network is assigned to the DH of the IPv4 network.
Means for acquiring an IPv4 address from a CPv4 server, and (b) IP of an IPv6 terminal of an IPv6 network
IP address conversion information holding means for holding the IPv6 address and the acquired IPv4 address in association with each other;
An IP transmitting / receiving means for transmitting / receiving an IPv4 packet to / from a Pv4 network and transmitting / receiving an IPv6 packet to / from an IPv6 network;
The fixed data is added to the IPv4 source address included in the Pv4 packet to convert the IPv4 source address into an IPv6 source address, and the IPv4 destination address included in the IPv4 packet is used for the corresponding IPv6 address held in the IP address conversion information holding unit. An IPv6 packet is created from an IPv4 packet by an IP header conversion for converting the IPv6 destination address into an IPv6 destination address, passed to the IP transmitting / receiving means and transmitted, and fixed data is deleted from the IPv6 destination address contained in the received IPv6 packet to delete the IPv6 destination address. And the IPv6 source address included in the IPv6 packet is converted to a corresponding IPv6 address held in the IP address translation information holding means.
To convert to IPv4 source address using 4 addresses
An IP header conversion unit that creates an IPv4 packet from an IPv6 packet by P header conversion, passes the packet to the IP transmission / reception unit, and transmits the packet. (E) Inquires from the IPv4 terminal of the IPv4 network the IP address for the domain name of the IPv6 terminal of the IPv6 network It receives and inquires the DNSv6 server of the IPv6 network to obtain an IPv6 address, and notifies the IPv4 address to the IPv4 terminal of the IPv4 network if the IPv4 address corresponding to the IPv6 address is stored in the IP address conversion information holding means. If the IPv4 address corresponding to the IPv6 address is not held in the IP address translation information holding means, the IPv4 address is obtained by the IPv4 address obtaining means, and IPv6 address with the acquired IP
v4 address is stored in the IP address conversion information storage means in association with the
Notify the IPv4 terminal of the v4 network,
An inquiry about the IP address for the domain name of the IPv4 terminal of the IPv4 network is received from the IPv6 terminal of the IPv6 network, and the D
Inquires the NSv4 server to obtain an IPv4 address, adds fixed data to the IPv4 address, and
v6 address, and the IPv6 address is
Notify the IPv6 terminal of the Pv6 network,
I corresponding to the IPv6 address of the IPv6 terminal of the IPv6 network that has queried the IP address for the domain name of the IPv4 terminal of the IPv4 network
It checks whether the IPv4 address is held in the IP address conversion information holding means, and if not, obtains the IPv4 address by the IPv4 address obtaining means, and associates the IPv6 address with the obtained IPv4 address. An IPv4-IPv6 conversion device characterized by comprising a DNS proxy means for holding the IP address conversion information holding means.

IPv4-IPv6 according to the third aspect
According to the conversion device, the IPv4-IPv4 of the first aspect is used.
6 communication method and IPv4-IPv6 of the second aspect
The communication method can be suitably implemented.

According to a fourth aspect, the present invention provides an I
In the Pv4-IPv6 translation device, the IP address translation information holding means deletes the held IPv6 addresses and IPv4 addresses that have not been referenced for a certain period of time, and sends the deleted IPv4 addresses to the DHCPv4 server of the IPv4 network. There is provided an IPv4-IPv6 conversion device characterized by returning.

IPv4-IPv6 according to the fourth aspect
According to the conversion device, the unused IPv4 address is DH
Since the data is returned to the CPv4 server, consumption of the IPv4 address can be suppressed.

According to a fifth aspect, the present invention provides an I
The Pv4-IPv6 translation device further comprises an IPv4 address pool unit for pooling a plurality of IPv4 addresses, and the IP address translation information holding unit is configured to activate the DH of the IPv4 network when the device is started.
Obtain a plurality of IPv4 addresses from the CPv4 server,
Pooled in the IPv4 address pool means,
An IPv4-IP, wherein an IPv4 address corresponding to an IPv6 address of an IPv6 terminal of a Pv6 network is obtained from the IPv4 address pool means.
A v6 converter is provided.

IPv4-IPv6 according to the fifth aspect
According to the conversion device, the load on the IPv4 network can be reduced as compared with acquiring IPv4 addresses one by one from a DHCPv4 server. According to a sixth aspect, the present invention provides an IPv4-IPv6 translating apparatus having the above configuration,
The present invention further provides an IPv4-IPv6 conversion device, further comprising DHCPv4 server means for dynamically allocating four addresses, wherein the DHCPv4 server means is used in place of the DHCPv4 server of the IPv4 network.

IPv4-IPv6 according to the sixth aspect
According to the conversion device, there is no need to provide a separate DHCPv4 server.

According to a seventh aspect, the present invention provides an image processing apparatus comprising:
In the Pv4-IPv6 translator, DNSv4 server means for managing domain information of the IPv4 network and D for managing domain information of the IPv6 network.
Further comprising NSv6 server means;
IPv4 server means and DNSv6 server means using the IPv4
4 network DNSv4 server and IPv6
Provided is an IPv4-IPv6 conversion device, which is used in place of a DNSv6 server of a network.

IPv4-IPv6 according to the seventh aspect
According to the conversion device, there is no need to separately provide a DNSv4 server or a DNSv6 server.

[0035]

Embodiments of the present invention will be described below with reference to the drawings.

(A) First Embodiment FIG. 1 shows an IPv4-I according to a first embodiment of the present invention.
It is a block diagram of the Pv6 conversion device 1a.

This IPv4-IPv6 conversion device 1a
It is located between an IPv4 network and an IPv6 network, and realizes communication between an IPv4 terminal and an IPv6 terminal by performing an IP header conversion between an IPv4 packet and an IPv6 packet.
, IP header conversion means 11, DNS proxy means 13
, An IPv4 address obtaining means 14 and an IP address conversion information holding means 15.

The IP transmission / reception means 10 communicates between an IPv4 network and an IPv6 network with an IPv4 network.
It is a means for transmitting and receiving packets and IPv6 packets, and is constituted by an electronic device such as a CPU or a RAM.

The IP header conversion means 11 is an IPv4
This is a means for performing IP header conversion between a packet and an IPv6 packet, and is constituted by an electronic device such as a CPU or a RAM.

[0040] The DNS proxy means 13 comprises an RFC 103
This is a means for acquiring domain information from a DNS server in an IPv4 network or a DNS server in an IPv6 network in accordance with the DNS technology described in, for example, RFC 4186, RFC 1886, and the like.

The IPv4 address obtaining means 14 is provided with
According to the DHCP technology described in FC1541, etc., a DHCP server in an IPv4 network
v4 address acquisition means such as CPU or R
It is composed of electronic devices such as AM.

The IP address conversion information holding means 15
Is a means for converting an IPv4 address to an IPv6 address, and is constituted by an electronic device such as a RAM, for example. The correspondence between IPv4 address and IPv6 address is I
It is held as a P address conversion table 151.

FIG. 2 shows an IP address conversion table 151.
FIG.

The I of the IPv6 terminal communicating with the IPv4 terminal
A Pv6 address and an IPv4 address dynamically assigned thereto are registered.

FIG. 3 is a schematic diagram of a communication network system 100 in which the IPv4 network 104 and the IPv6 network 106 are connected via the IPv4-IPv6 converter 1a.

The IPv4 network 104 has an IPv4
In addition to the four terminals 2, a DNSv4 server 3 that manages domain information in the IPv4 network 104 and a DHCPv4 server 4 that dynamically allocates IPv4 addresses to terminals in the IPv4 network 104 are connected.

The IPv6 network 106 has an IPv6
In addition to the six terminals 5, a DNSv6 server 6 that manages domain information in the IPv6 network is connected.

Here, 133.144.95.101 is assigned as the IPv4 address to the IPv4 terminal 2, and 1 :: as the IPv6 address to the IPv6 terminal 5.
It is assumed that 1 is assigned. Also, DHCPv
4 server 4 has 133.144.95.1 to 133.1
It is assumed that 100 IPv4 addresses of 44.95.100 are pooled. Also, the IPv4 terminal 2 and the IPv6 terminal 5 have an IPv4-terminal as a DNS server.
It is assumed that the IPv6 translator 1a has been set. Further, in the IPv4-IPv6 conversion device 1a, a DNSv4 server 3 and a DNSv6 server 6 are set as DNS servers, and a DHCPv server is used as a DHCP server.
It is assumed that four servers 4 have been set.

In FIG. 3, the IPv4 network 1
Although the IP network 04 and the IPv6 network 106 are completely separated, the same applies to a case where the IPv4 network and the IPv6 network coexist in the same physical network.

FIGS. 4 and 5 show the case where the IPv4 terminal 2
6 is a flowchart of an operation when starting communication to a terminal 5.

Since the IPv4 terminal 2 knows the domain name of the IPv6 terminal 5 but does not know the IP address, as shown in FIG. 4, an inquiry message of an IP address corresponding to the domain name of the IPv6 terminal 5 (hereinafter, referred to as FIG. 4) , "Message A") to the IPv4-IPv6 translator 1a via the IPv4 network 104, and then waits for a response for a certain period of time.

The IP transmission / reception means 10 of the IPv4-IPv6 conversion device 1 a receives the message A, passes it to the DNS proxy means 13, and passes it. The DNS acting unit 13 instructs the IP transmitting / receiving unit 10 to transfer the message A to the DNSv4 server 3 and then waits for a response for a certain period of time. IP
The transmission / reception means 10 transfers the message A to the DNSv4 server 3 via the IPv4 network.

The DNSv4 server 3 which has received the message A searches the domain information of the IPv6 terminal 5, but does not return a response to the message A if it is not registered.

The DNS acting unit 13 which has not received a response from the DNSv4 server 3 even after a certain period of time has passed the command A to the IP transmitting / receiving unit 10 to transfer the message A to the DNSv6 server 6, Wait for a response.
The IP transmission / reception means 10 transfers the message A to the DNSv6 server 6 via the IPv6 network.

The DNSv6 server 6 which has received the message A searches the domain information of the IPv6 terminal 5 and sends the registered domain information of the IPv6 terminal 5 to the message A.
Is returned to the IPv4-IPv6 translator 1a as a response message (hereinafter referred to as "message B") to the IPv4 / IPv6 translator 1a.
The IP transmitting / receiving means 1 of the IPv4-IPv6 translator 1a which has received the response from the DNSv6 server 6 within a certain time
0 passes the received message B to the DNS proxy 13. The DNS proxy 13 sends the message B
6 obtains an IPv6 address (1 :: 1) corresponding to the domain name of the terminal 5, and stores the IP address conversion information holding means 1
Pass to 5. The IP address conversion information holding unit 15
The IP address conversion table 151 is searched using the IPv6 address (1 :: 1) of the v6 terminal 5 as a key. If a corresponding entry is registered, the IPv4 address of that entry is registered.
The address is returned to the DNS proxy 13. On the other hand, if the corresponding entry is not registered, the fact is notified to the DNS proxy means 1
Notify 3.

From the IP address conversion information holding means 15 to I
Upon receiving the Pv4 address, the DNS acting unit 13 creates a message (hereinafter, referred to as "message E") notifying the IPv4 address as an IPv4 address corresponding to the domain name of the IPv6 terminal 5, and transmits this message to the IP transmitting / receiving unit. Hand over to 10. The IP transmitting / receiving means 10 transmits the message E to the IPv4 terminal 2 via the IPv4 network.

On the other hand, the IP address conversion information holding means 15
Receives the notification that the entry has not been registered from the DNS proxy unit 13 and sends the IPv4 address acquisition unit 14 an IPv4 address.
After instructing the acquisition of four addresses, it waits for a response for a certain period of time.
The IPv4 address acquisition means 14 creates an IPv4 address acquisition message (hereinafter, referred to as “message C”), and sends the message to the DHCPv4 server 4 so as to transfer it to the DHCPv4 server 4.
After giving the instruction to the P transmission / reception means 10, it waits for a response for a certain period of time. The IP transmitting / receiving means 10 transmits the message C to the IPv4
The data is transmitted to the DHCPv4 server 4 via the network.

The DHCPv4 server 4 receiving the message C sends the IPv6 address (1 :: 1) of the IPv6 terminal 5
Is assigned an IPv4 address (here, 133.14).
It is assumed that 4.95.1 has been assigned. ), And returns an IPv4 address assignment message (hereinafter, referred to as “message D”).

IP transmitting / receiving means 1 receiving message D
0 passes the message D to the IPv4 address acquisition means 14. The IPv4 address acquiring means 14 sends the message D
And obtains the IPv4 address (133.144.95.1) from the DNS server 13 and notifies the DNS proxy 13 of the address. The DNS acting means 13 sends the IPv4 address (133.144.95.
1) the IP corresponding to the domain name of the IPv6 terminal 5
A message E to be notified as an address is created and passed to the IP transmitting / receiving means 10. The IP transmitting / receiving means 10 transmits the message E to the IPv4 terminal 2 via the IPv4 network. In addition, the DNS proxy means 13 uses DHCP
IPv4 address acquired from the v4 server 4 (133.
144.95.1) is associated with the IPv6 address (1 :: 1) of the IPv6 terminal 5 and passed to the IP address conversion information holding means 15. IP address conversion information holding means 15
Creates a new entry in the IP address conversion table 151 and stores the IPv4 address (133.144.95.
1) and the IPv6 address (1 :: 1) of the IPv6 terminal 5
Register the correspondence. Note that the IP address conversion table 1
The entry 51 is deleted if it is not referenced for a certain period of time, and the IPv4 address (133.144.95.1) is returned to the DHCPv4 server 4.

As shown in FIG. 5, the IPv4 terminal 2
The IPv4 address notified by the message E from the Pv4-IPv6 translation device 1a (133.144.95.
1) is set in the IPv4 destination address field of the IPv4 packet and the own IPv4 address (13
An IPv4 packet in which 3.144.95.101) is set in the IPv4 source address field is sent to the IPv4-IPv6 translator 1a via the IPv4 network.
Send to

The IP transmission / reception means 10 of the IPv4-IPv6 conversion device 1a passes the received IPv4 packet to the IP header conversion means 11. The IP header conversion means 11
The IPv4 address (133.144.95.101) is extracted from the IPv4 source address field of the Pv4 packet, and the above-mentioned fixed pattern of 96 bits is added to the 128-bit “IPv4-mapped IPv6 address” (:: FFFF: 133). .144.95.101)
And set this in the IPv6 source address field of the IPv6 packet. Further, the IP header conversion means 11 converts the IPv4 address (133.144.9) from the IPv4 destination address field of the IPv4 packet.
5.1) is taken out and passed to the IP address conversion information holding means 15. IP address conversion information holding means 15
Refers to the IP address conversion table 151, and
An IPv6 address (1 :: 1) corresponding to the v4 address (133.144.95.1) is obtained and passed to the IP header conversion means 11. The IP header conversion means 11 uses the IPv6
IPv6 in the IPv6 destination address field of the packet
Address (1 :: 1) is set. Then, the IPv6 packet created by performing the IP header conversion is transferred to the IP transmission / reception unit 10. The IP transmitting / receiving means 10
The Pv6 packet is transmitted over the IPv6 network via the I6
It transmits to the Pv6 terminal 5.

As described above, from the IPv4 terminal 2 to the IPv6 terminal
Communication to the terminal 5 can be started.

FIG. 6 and FIG. 7 show that the IPv6 terminal 5
4 is a flowchart of an operation when starting communication to four terminals 2.

Since the IPv6 terminal 5 knows the domain name of the IPv4 terminal 2 but does not know the IP address, as shown in FIG. 6, an inquiry message of an IP address corresponding to the domain name of the IPv4 terminal 2 (hereinafter, referred to as FIG. 6) , "Message K") via the IPv6 network 106 to the IPv4-IPv6 translator 1a, and then waits for a response for a certain period of time.

The IP transmission / reception means 10 of the IPv4-IPv6 conversion device 1a receives the message K and passes it to the DNS proxy means 13. The DNS acting means 13 instructs the IP transmitting / receiving means 10 to transfer the message K to the DNSv6 server 6, and then waits for a response for a certain period of time. IP
The transmission / reception means 10 transfers the message K to the DNSv6 server 6 via the IPv6 network.

The DNSv6 server 6 that has received the message K searches the domain information of the IPv4 terminal 2, but does not return a response to the message K if it is not registered.

The DNS acting means 13 which has not received a response from the DNSv6 server 6 even after a certain time has passed, instructs the IP transmitting / receiving means 10 to transfer the message K to the DNSv4 server 3, and then passes the message K for a certain time. Wait for a response.
The IP transmission / reception means 10 transfers the message K to the DNSv4 server 3 via the IPv4 network.

The DNSv4 server 3 that has received the message K searches the domain information of the IPv4 terminal 2 and sends the registered domain information of the IPv4 terminal 2 to the message K.
Is returned to the IPv4-IPv6 translation device 1a as a response message (hereinafter, referred to as “message L”) to the IPv4 / IPv6 translator 1a.

The IP transmission / reception means 10 of the IPv4-IPv6 conversion device 1 a having received the response from the DNSv4 server 3 within a certain time passes the received message L to the DNS proxy means 13. The DNS proxy means 13 sends the message L
To IPv4 corresponding to the domain name of IPv4 terminal 2
4 addresses (133.144.95.101) are obtained.

Next, the DNS proxy unit 13 passes the IPv6 address (1 :: 1) of the IPv6 terminal 5 to the IP address conversion information holding unit 15. The IP address conversion information holding unit 15 uses the IPv6 address (1 :: 1) of the IPv6 terminal 5 as a key to set the IP address conversion table 1
51, and notifies the DNS substituting means 13 whether or not the corresponding entry is registered.

Upon receiving the notification that the entry corresponding to the IPv6 address (1 :: 1) of the IPv6 terminal 5 has not been registered, the DNS acting unit 13 instructs the IPv4 address acquiring unit 14 to acquire an IPv4 address. Wait for a response for a certain time. IPv4 address acquisition means 1
4 creates an IPv4 address acquisition message (hereinafter, referred to as “message M”) and sends it to DHCPv4.
After instructing and transmitting the IP transmitting / receiving means 10 to transfer the data to the server 4, a response is waited for a predetermined time. IP transmitting / receiving means 10
Sends the message M via the IPv4 network to the DHC
It transmits to the Pv4 server 4.

The DHCPv4 server 4 which has received the message M sends the IPv6 address (1 :: 1) of the IPv6 terminal 5
Is assigned an IPv4 address (here, 133.14).
It is assumed that 4.95.1 has been assigned. ), And returns an IPv4 address assignment message (hereinafter, referred to as “message N”).

IP transmitting / receiving means 1 receiving message N
0 passes the message N to the IPv4 address acquisition means 14. The IPv4 address acquisition means 14 sends the message N
And obtains the IPv4 address (133.144.95.1) from the DNS server 13 and notifies the DNS proxy 13 of the address. The DNS acting means 13 sends the IPv4 address (133.144.95.1) acquired from the DHCPv4 server 4 to the IPv6 terminal 5.
In correspondence with the IPv6 address (1 :: 1). The IP address conversion information holding means 15 includes an IP address conversion table 151.
Creates a new entry in the IPv4 address (13
3.144.95.1) and the IPv6 address (1 :: 1) of the IPv6 terminal 5 are registered. The entry in the IP address conversion table 151 is deleted when it is not referred for a certain period of time, and the IPv4 address (133.1) is deleted.
44.95.1) is returned to the DHCPv4 server 4.

A notification that an entry corresponding to the IPv6 address (1 :: 1) of the IPv6 terminal 5 is registered or a registration of an entry corresponding to the IPv6 address (1 :: 1) of the IPv6 terminal 5 is received. Upon completion, the DNS proxy unit 13 sets the IPv4 terminal 2
“IPv4-mapped IPv6 address” with the address (133.144.99.501) set (:: FFFF:
133.144.95.101) as a message notifying the IP address corresponding to the domain name of the IPv4 terminal 2 (hereinafter referred to as “message P”), and transferring the message to the IPv6 terminal 5. It instructs and passes to the IP transmitting / receiving means 10. The IP transmitting / receiving means 10 transmits the message P to the IPv6 terminal 5 via the IPv6 network.
Send to

As shown in FIG. 7, the IPv6 terminal 5
IPv6 notified from the Pv4-IPv6 conversion device 1a
Address (:: FFFF: 133.144.95.10
1) is set in the IPv6 destination address field of the IPv6 packet, and the own IPv6 address (1 :: 1) is set.
With IPv6 set in the IPv6 source address field
6 packets over an IPv6 network
It transmits to the 4-IPv6 conversion device 1a.

The IP transmission / reception means 10 of the IPv4-IPv6 conversion device 1a passes the received IPv6 packet to the IP header conversion means 11. The IP header conversion means 11
From the IPv6 destination address field of the Pv6 packet, the IPv6 address (:: FFFF: 133.144.9)
5.101), and removes the 96-bit fixed pattern described above to remove the 32-bit IPv4 address "(1
33.144.95.101) and convert it to IPv4
Set in the IPv4 destination address field of 4 packets. Further, the IP header conversion unit 11 extracts the IPv6 address (1 :: 1) from the IPv6 transmission address field of the IPv6 packet, and passes this to the IP address conversion information holding unit 15. The IP address conversion information holding unit 15 refers to the IP address conversion table 151 and refers to the IPv4 address (1 :: 1) corresponding to the IPv4 address.
The address (133.144.95.1) is obtained and passed to the IP header conversion means 11. The IP header conversion means 11
The IPv4 address (133.144.95.1) is set in the IPv4 source address field of the IPv4 packet. Then, the IPv4 packet created by performing the IP header conversion is transferred to the IP transmitting / receiving means 10.
The IP transmission / reception means 10 converts the IPv4 packet into an IPv4 packet.
The data is transmitted to the IPv4 terminal 2 via the network.

As described above, from the IPv6 terminal 5 to the IPv4 terminal
Communication to the terminal 2 can be started.

In the above description, the case where the IPv4 domain information is registered in the DNSv4 server 3 has been described. However, the IPv4 domain information may be registered in the DNSv6 server 6. In this case, IPv4-IPv6
The conversion device 1a uses a DNSv
6 to obtain IPv4 domain information by communicating with the server 6. Similarly, the IPv6 domain information is
It may be registered in the NSv4 server 3. in this case,
The IPv4-IPv6 translator 1a communicates with the DNSv4 server 3 using the IPv4 protocol, thereby
Obtain Pv6 domain information.

In other words, the case has been described where the IPv4 network 104 and the IPv6 network 106 are separate domains, but one domain information is stored in a state where the IPv4 network 104 and the IPv6 network 106 are mixed in one and the same domain. DNS
It may be managed by a server.

Also, from the IPv4 terminal 2 to the IPv6 terminal 5
When the communication to the IPv6 terminal 5 is started, the IPv4-IPv6 translator 1 a
Upon receiving the address inquiry message A, the DN
Forward message A to Sv4 server 3, ie DNS
Although the inquiry about the IPv4 address is made to the v4 server 3, the inquiry about the IPv6 address may be made to the DNSv4 server 3 accordingly. Similarly, the message A is transferred to the DNSv6 server 6, that is, the DNSv6 server 6 is inquired about the IPv6 address. However, the DNSv6 server 6 may be inquired about the IPv4 address.

Further, from the IPv6 terminal 5 to the IPv4 terminal 2
When the communication to the IPv4 terminal 2 is started, the IPv4-IPv6 translator 1 a
Upon receiving the address inquiry message K, the DN
Forwards message K to Sv6 server 6, ie DNS
Although the inquiry about the IPv6 address is made to the v6 server 6, an inquiry about the IPv4 address may be made to the DNSv6 server 6 in accordance with the inquiry. Similarly, the message K is transferred to the DNSv4 server 3, that is, the DNSv4 server 3 is inquired about the IPv4 address. However, the DNSv4 server 3 may be inquired about the IPv6 address.

Also, from the IPv4 terminal 2 to the IPv6 terminal 5
When the communication to the IPv6 terminal 5 is started, the IPv4-IPv6 translator 1 a
When the inquiry message A of the address is received, the message A is first transferred to the DNSv4 server 3, and the message A is transferred to the DNSv6 server 6 when the answer is not obtained after waiting for a predetermined time.
The message A may be transferred to both the v4 server 3 and the DNSv6 server 6 at the same time. When it is possible to determine from the domain name of the IPv6 terminal 5 that the domain information is managed by the DNSv6 server 6, or when the DNSv6
4 If it can be determined that the data is not managed by the server 3,
The message A may be transferred only to the NSv6 server 6. Further, when the message A is transferred to the DNSv4 server 3 and a reply indicating that there is no corresponding entry is obtained, the DNSv4
6 The message A may be transferred to the server 6.

Also, from the IPv6 terminal 5 to the IPv4 terminal 2
When the communication to the IPv4 terminal 2 is started, the IPv4-IPv6 translator 1 a
When the address inquiry message K is received, the message K is first transferred to the DNSv6 server 6, and the message K is transferred to the DNSv4 server 3 when a response is not obtained after waiting for a predetermined time.
The message K may be transferred to both the v6 server 6 and the DNSv4 server 3 at the same time. When it is possible to determine from the domain name of the IPv4 terminal 2 that the domain information is managed by the DNSv4 server 3 or when the DNSv4
6 If it can be determined that it is not managed by the server 6,
The message K may be transferred only to the NSv4 server 3. Also, when the message K is transferred to the DNSv6 server 6 and an answer indicating that there is no corresponding entry is obtained, the DNSv6
The message K may be transferred to the four servers 3.

Also, from the IPv6 terminal 5 to the IPv4 terminal 2
When starting communication to IPv6, the IPv4 address is set to DHCP.
The process of acquiring from the v4 server 4 and registering it in the IP address conversion table 115 in association with the IPv6 address of the IPv6 terminal 5 is performed by sending an inquiry message K for an IP address corresponding to the domain name of the IPv4 terminal 2 to
Although it is performed when receiving from terminal 5, in FIG.
The IPv4-IPv6 translator 1a converts the IPv6 packet sent from the IPv6 terminal 5 into an IPv4 packet.
It may be performed when performing P header conversion and relaying. By doing so, the IPv4-terminal 5 sends the IPv4-I
It is possible to cope with a case where the domain information inquiry to the Pv6 converter 1a is not directly performed, that is, a case where the inquiry is performed via another DNS server.

Further, I in the IPv6 network
The IP address of the IPv4 terminal 2
A case has been described in which a 128-bit “IPv4-mapped IPv6 address” is used in which the aforementioned 96-bit fixed pattern is added to the Pv4 address, but a DHCP server is provided in the IPv6 network 106 and
An IPv6 address acquiring means is provided inside the Pv4-IPv6 translation device 1a to acquire an IPv6 address, and
It may be associated with the IPv4 address of the terminal 2 and use the IPv6 address. Specifically, when starting communication from the IPv4 terminal 2 to the IPv6 terminal 5, in FIG. 5, the IPv4-IPv6 translation device 1a converts the IPv4 packet sent from the IPv4 terminal 2 into an IPv6 packet by an IP header. When the packet is relayed, the source address is used as the destination address of the IPv4 packet, and the IP address conversion table 15 of the IP address conversion information holding unit 15 is used.
1 is retrieved and converted to the IPv6 address of the corresponding entry. At this time, if there is no corresponding entry, an IPv6 address is obtained from the DHCP server in the IPv6 network 106, registered in the IP address conversion table 151 in association with the source address of the IPv4 packet, and converted into the IPv6 address. On the other hand, IPv6
When starting communication from the terminal 5 to the IPv4 terminal 2,
In FIG. 6, when the IPv4-IPv6 translation device 1a obtains the IPv4 address of the IPv4 terminal 2 by the message L, the IPv4 address is searched in the IP address translation table 151 of the IP address translation information holding means 15, and the IPv6 address of the corresponding entry is retrieved. Address P
As At this time, if there is no corresponding entry,
6 from a DHCP server in the network 106 to IPv6
An address is acquired, registered in the IP address conversion table 151 in association with the IPv4 address of the IPv4 terminal 2, and the IPv6 address is returned as a message P. Further, the IPv4-IPv6 translation device 1a shown in FIG.
When an IPv6 packet sent from the IPv6 terminal 5 is converted into an IPv4 packet by an IP header and relayed,
As in the case of the source address of the IPv6 packet, the IP address conversion table 151 of the IP address conversion information holding unit 15 is searched with the destination address, and converted to the IPv4 address of the corresponding entry.

Also, the description has been made of the case where the entry of the IP address conversion table 151 is deleted when it is not referred for a certain period of time. However, the entry registered for connection communication is deleted immediately after the connection is disconnected. May be.

Although the IPv4 address has been described using a global address, a private address described in RFC1918 may be used. Similarly, IP
Although the v6 address has been described using the global address, a site local address or a link local address described in RFC1884 may be used.

The conversion of the address is described in the aforementioned 9
Although the case where the address field is used alone by referring to the fixed pattern addition / deletion for 6 bits or the IP address conversion table 151 has been described, the method called IP masquerade is used for the address of the terminal that has started communication. Using the address of the terminal that initiated the communication and the TCP (Transmission Control Protocol) /
The combination of the port number of UDP (User Datagram Protocol) is determined by the address of the IPv4-IPv6
Conversion with a combination of / UDP port numbers may be performed.

The entry and deletion of the entry of the IP address conversion table 151 are automatically performed by the IPv4-IPv6 translation device 1a in cooperation with the DNSv4 server 3, the DNSv6 server 6, and the DHCPv4 server 4, but the IPv4-IPv6 translation device 1a automatically registers and deletes the entry. A management terminal for the IPv6 translator 1a may be provided to allow the administrator to manually perform the operation.

Even when the IPv4-IPv6 translator 1a automatically registers and deletes entries in the IP address conversion table 151, it is possible to limit the entries that can be registered and deleted by the setting of the administrator. good. Specifically, the IP address (for example, 133.144.96.101) of a certain IPv4 terminal is I
By limiting the P-address translation table 151 so that it cannot be registered, the IPv6 network may be prevented from accessing this IPv4 terminal.

(B) Second Embodiment FIG. 8 shows an IPv4-I according to a second embodiment of the present invention.
It is a block diagram of the Pv6 converter 1b.

This IPv4-IPv6 translator 1b is
This is a configuration in which an IPv4 address pool unit 16 is added to the IPv4-IPv6 translation device 1a of FIG.

When the IPv4-IPv6 translator 1b is started up, the IPv4 address acquiring means 14 sends the DHCP
A plurality of IPv4 addresses are collectively acquired from the v4 server 4 and pooled in the IPv4 address pooling means 16. Then, when the communication between the IPv4 terminal 2 and the IPv6 terminal 5 starts, the IPv4 address acquiring means 14
Obtains an IPv4 address from the IPv4 address pool unit 16.

The use of the IPv4-IPv6 translator 1b makes it possible to reduce the load on the IPv4 network 104 as compared with acquiring IPv4 addresses one by one from the DHCPv4 server 4.

(C) Third Embodiment FIG. 9 shows an IPv4-I according to a third embodiment of the present invention.
It is a block diagram of the Pv6 converter 1c.

This IPv4-IPv6 translator 1c is
Instead of the IPv4 address acquisition means 14 of the IPv4-IPv6 translator 1a of FIG. 1, the DHCPv4 server means 1
7 is provided.

By using this IPv4-IPv6 translator 1c, it is not necessary to provide a separate DHCPv4 server 4.

(D) Fourth Embodiment FIG. 10 is a block diagram showing an IPv4 according to a fourth embodiment of the present invention.
FIG. 3 is a configuration diagram of an IPv6 translator 1d.

This IPv4-IPv6 translator 1d is
The IPv4-IPv6 translator 1a shown in FIG.
This is a configuration in which a server unit 18 and a DNSv6 server unit 19 are added.

If this IPv4-IPv6 conversion device 1d is used, it is not necessary to provide the DNSv4 server 3 or the DNSv6 server 6 separately.

(E) Fifth Embodiment Next, a fifth embodiment will be described with reference to FIGS. 11, 12, and 13. FIG.

FIG. 11 shows a communication network system 108 connecting an IPv6 network 106 and an IPv6 network 107 with the IPv4 network 104 interposed therebetween.
FIG. This communication network system 108
Is a communication network system 100 shown in FIG.
This is a configuration in which a network 107 is added. The IPv6 network 107 is connected to the IPv4-IPv6 translator 11
1 is connected to the IPv4 network 104.

The IPv6 network 107 has an IPv6
In addition to the six terminals 115, a DNSv6 server 116 that manages domain information in the IPv6 network 107 is connected.

Here, the IPv6 terminal 115 has the IPv6
It is assumed that 2 :: 1 is assigned as an address. In addition, 133.144.
In addition to the 100 IPv4 addresses from 95.1 to 133.144.95.100, 133.144.96.1
100 IPv4 of ~ 133.144.96.100
Assume that addresses are pooled. Also, IPv
6 terminal 115 has an IPv4-IP as a DNS server.
It is assumed that the v6 conversion device 111 has been set. In the IPv4-IPv6 conversion device 111, it is assumed that the DNSv6 server 116 is set as the DNS server and the DHCPv4 server 4 is set as the DHCP server. Also, the IPv4-IPv6 translator 1 has an IPv4 DNS server as an upper-level domain.
It is assumed that the 4-IPv6 conversion device 111 has been set.

FIG. 12 and FIG.
It is a flowchart of the operation | movement at the time of starting communication with the Pv6 terminal 115.

Since the IPv6 terminal 5 knows the domain name of the IPv6 terminal 115, but does not know the IP address, as shown in FIG. 12, an inquiry message (hereinafter, referred to as an IP address corresponding to the domain name of the IPv6 terminal 115) is made as shown in FIG. , "Message Q").
After transmitting to the IPv4-IPv6 conversion device 1 via the network 106, the system waits for a response for a certain period of time.

The IP transmission / reception means 10 of the IPv4-IPv6 conversion apparatus 1 receives the message Q and passes it to the DNS proxy means 13. The DNS proxy 13 sends the message Q
Is instructed to transfer to the IPv4-IPv6 translator 111 to the IP transmission / reception means 10, and then waits for a response for a certain period of time. The IP transmission / reception means 10 transmits the message Q
IPv4-IPv6 translator 11 via 4 networks
Transfer to 1.

The IP address of the IPv4-IPv6 translator 111
The transmitting / receiving means 10 receives the message Q and performs DNS processing.
Hand over to proxy means 13. The DNS proxy unit 13 instructs the IP transmitting / receiving unit 10 to transfer the message Q to the DNSv6 server 116, and then waits for a response for a certain period of time. The IP transmitting / receiving unit 10 sends the message Q to the DNSv6 server 116 Transfer to

The DNSv6 server 116 that has received the message Q searches for the domain information of the IPv6 terminal 115, and registers the registered domain information of the IPv6 terminal 115 as a response message to the message Q (hereinafter, referred to as “message R”). To the IPv4-IPv6 translator 111.

The IP transmitting / receiving means 10 of the IPv4-IPv6 translator 111, which has received the response from the DNSv6 server 116 within a certain time, converts the received message R into a DN.
It passes to S acting means 13. The DNS proxy unit 13 obtains an IPv6 address (2 :: 1) corresponding to the domain name of the IPv6 terminal 115 from the message R, and passes it to the IP address conversion information holding unit 15. The IP address conversion information holding unit 15 searches the IP address conversion table 151 using the IPv6 address (2 :: 1) of the IPv6 terminal 115 as a key, and if a corresponding entry is registered, the IP address of the entry is stored in the DNS. Return it to proxy means 13. On the other hand, if the corresponding entry is not registered, the fact is notified to the DNS substituting means 13.

From the IP address conversion information holding means 15 to I
Upon receiving the Pv4 address, the DNS acting unit 13 creates a message (hereinafter, referred to as “message U”) for notifying the IPv4 address as an IPv4 address corresponding to the domain name of the IPv6 terminal 115, and transmits this message to the IP transmitting / receiving unit. Hand over to 10. IP transmitting / receiving means 10
Sends the message U over the IPv4 network
It transmits to the 4-IPv6 conversion device 1.

On the other hand, the IP address conversion information holding means 15
Receives the notification that the entry has not been registered from the DNS proxy unit 13 and sends the IPv4 address acquisition unit 14 an IPv4 address.
After instructing the acquisition of four addresses, it waits for a response for a certain period of time.
The IPv4 address acquisition means 14 creates an IPv4 address acquisition message (hereinafter, referred to as “message S”) and sends the message to the DHCPv4 server 4 so as to transfer it to the DHCPv4 server 4.
After giving the instruction to the P transmission / reception means 10, it waits for a response for a certain period of time. The IP transmitting / receiving means 10 transmits the message S to the IPv4
The data is transmitted to the DHCPv4 server 4 via the network.

The DHCPv4 server 4 that has received the message S sends the IPv6 address (2 ::
1) with an IPv4 address (here, 133.
144.96.1 has been assigned. ), IPv6
A 4-address assignment message (hereinafter, referred to as "message T") is returned.

IP transmitting / receiving means 1 receiving message T
0 passes the message T to the IPv4 address acquisition means 14. The IPv4 address acquiring means 14 sends the message T
And obtains an IPv4 address (133.144.96.1) from the server and notifies the DNS proxy 13 of the address. The DNS proxy 13 sends the IPv4 address (133.144.96.
A message U for notifying 1) as an IP address corresponding to the domain name of the IPv6 terminal 115 is created, and this is passed to the IP transmitting / receiving means 10. IP transmitting / receiving means 10
Sends the message U over the IPv4 network
It transmits to the 4-IPv6 conversion device 1. In addition, the DNS acting means 13 transmits the IPv4 acquired from the DHCPv4 server 4.
The four addresses (133.144.96.1) are passed to the IP address conversion information holding unit 15 in association with the IPv6 addresses (2 :: 1) of the IPv6 terminal 115. The IP address conversion information holding unit 15 creates a new entry in the IP address conversion table 151, and stores the IPv4 address (133.144.96.1) and the IPv6 terminal 115.
The correspondence of the IPv6 address (2 :: 1) is registered. Note that the entry of the IP address conversion table 151 is deleted if it is not referred for a certain period of time, and the IPv4 address (133.144.96.1) is deleted from the DHCPv4 server 4.
Will be returned to

The IP transmitting / receiving means 10 of the IPv4-IPv6 translator 1 which has received the response from the IPv4-IPv6 translator 111 within a certain period of time,
Is passed to the DNS proxy unit 13. The DNS proxy means 13
From the message U, an IPv4 address (133.144.96.
Obtain 1). The DNS acting unit 13 sets the “IPv4-mapped IPv6 address” (:: F) in which the IPv4 address (133.144.96.1) obtained from the message U is set.
FFF: 133.144.96.1) to IPv6 terminal 1
A message notified as an IP address corresponding to the 15 domain names (hereinafter, referred to as “message V”).
And transfer it to the IPv6 terminal 5 so that I
It is instructed and passed to the P transmitting / receiving means 10. IP transmitting / receiving means 10
Sends the message V over the IPv6 network
6 Transmit to terminal 5.

As shown in FIG. 13, the IPv6 terminal 5
IPv6 notified from the IPv4-IPv6 translation device 1
Address (:: FFFF: 133.144.96.1)
Is set in the IPv6 destination address field of the IPv6 packet, and its own IPv6 address (1 :: 1) is set to I
The IPv6 packet set in the Pv6 originating address field is sent to the IPv4 network via the IPv6 network.
It transmits to the IPv6 translator 1.

[0117] The IP transmitting / receiving means 10 of the IPv4-IPv6 conversion device 1 passes the received IPv6 packet to the IP header conversion means 11. The IP header conversion means 11
I6 from the IPv6 destination address field of the v6 packet
Pv6 address (:: FFFF: 133.144.9)
6.1), and removes the 96-bit fixed pattern described above to remove the 32-bit IPv4 address "(13
3.144.96.1) and set this in the IPv4 destination address field of the IPv4 packet.
Further, the IP header conversion unit 11 extracts the IPv6 address (1 :: 1) from the IPv6 transmission address field of the IPv6 packet, and passes this to the IP address conversion information holding unit 15.

The IP address conversion information holding means 15
The IP address conversion table 151 is searched using the IPv6 address (1 :: 1) of the Pv6 terminal 5 as a key, and the IP header conversion unit 11 is notified of whether or not the corresponding entry is registered.

The IP header converting means 11 which has received the notification that the entry corresponding to the IPv6 address (1 :: 1) of the IPv6 terminal 5 has not been registered instructs the IPv4 address obtaining means 14 to obtain the IPv4 address. After that, wait for a response for a certain time. The IPv4 address acquisition means 14 creates an IPv4 address acquisition message (hereinafter, referred to as “message W”) and sends it to the DHCPv.
After instructing and transmitting the IP transmitting / receiving means 10 to transfer the data to the four servers 4, a response is waited for a predetermined time. IP transmitting / receiving means 1
0 indicates that the message W is transmitted via the IPv4 network to the DH
It is transmitted to the CPv4 server 4.

The DHCPv4 server 4 receiving the message W sends the IPv6 address (1 :: 1) of the IPv6 terminal 5
Is assigned an IPv4 address (here, 133.14).
It is assumed that 4.95.1 has been assigned. ), And returns an IPv4 address assignment message (hereinafter, referred to as “message X”).

IP transmitting / receiving means 1 receiving message X
0 passes the message X to the IPv4 address acquisition means 14. The IPv4 address acquisition means 14 sends the message X
And obtains the IPv4 address (133.144.95.1) from the IP address, and notifies the IP header conversion unit 11 of the address. The IP header conversion means 11 obtains the IP header obtained from the DHCPv4 server 4
IPv4 address (133.144.95.1)
It is passed to the IP address conversion information holding means 15 in association with the IPv6 addresses (1 :: 1) of the six terminals 5. The IP address conversion information holding unit 15 creates a new entry in the IP address conversion table 151, and stores the IPv4 address (133.144.95.1) and the IP address of the IPv6 terminal 5.
The correspondence of the Pv6 address (1 :: 1) is registered. In addition,
The entry of the IP address conversion table 151 is deleted when it is not referred for a certain period of time, and the IPv4 address (1
33.144.95.1) is returned to the DHCPv4 server 4.

A notification that an entry corresponding to the IPv6 address (1 :: 1) of the IPv6 terminal 5 is registered or a registration of an entry corresponding to the IPv6 address (1 :: 1) of the IPv6 terminal 5 is received. Upon completion, the IP header conversion means 11 sends the I
In the IPv4 source address field, enter the IPv4 address (1
33.144.95.1) is set. Then, the IPv4 packet created by performing the IP header conversion is transferred to the IP transmitting / receiving means 10. IP transmitting / receiving means 10
Transmits an IPv4 packet to the IPv4-IPv6 translator 111 via the IPv4 network.

The IP address of the IPv4-IPv6 translator 111
The transmission / reception unit 10 passes the received IPv4 packet to the IP header conversion unit 11. The IP header conversion means 11
The IPv4 address (133.144.95.1) is extracted from the IPv4 source address field of the IPv4 packet, and the above-mentioned fixed pattern of 96 bits is added to the 128-bit “IPv4-mapped IPv6 address” (:: FFFF: 133). .144.95.1) and set this in the IPv6 source address field of the IPv6 packet. IP header conversion means 1
1 is an IPv4 address (133.144.96.1) from the IPv4 destination address field of the IPv4 packet.
1) is taken out and passed to the IP address conversion information holding means 15. The IP address conversion information holding means 15
Referring to the P address conversion table 151, the IPv4 address (133.144.96.1) corresponding to the IPv4 address
6 address (2 :: 1) and obtains the IP header conversion means 1
Pass to 1. The IP header conversion means 11 sets the IPv6 address (2 :: 1) in the IPv6 destination address field of the IPv6 packet. And like this, IP
The IPv6 packet created by performing the header conversion is passed to the IP transmitting / receiving means 10. The IP transmission / reception means 10 uses the IPv6
The packet is transmitted over the IPv6 network via the IPv6 network.
Transmit to terminal 115.

As described above, the IPv6 terminal 5 sends the IPv6
Communication to the terminal 115 can be started.

In the above description, the IPv6 terminal 5 sends the IP
Although the case where the communication to the v6 terminal 115 is started has been described, the same applies to the case where the communication from the IPv6 terminal 115 to the IPv6 terminal 5 is started.

In the above description, the communication between two IPv6 terminals when the IPv4 network is on the communication path has been described. However, the communication between the two IPv4 terminals when the IPv6 network is on the communication path is described. The same is true for communication between devices.

In the above description, the communication between two IPv6 terminals when only one IPv4 network exists on the communication path has been described.
The same applies to communication between two IPv6 terminals when there is a v4 network and an IPv6 network, communication between two IPv4 terminals, and communication between an IPv4 terminal and an IPv6 terminal.

[0128]

According to the IPv4-IPv6 communication method and the IPv4-IPv6 conversion device of the present invention, only the IPv6 protocol is mounted on the IPv6 terminal, and the
Even if an IPv4 terminal is not assigned, an IPv4 terminal and an IP
Communication between v6 terminals becomes possible. Further, since the other party can be specified by the domain name instead of the actual IP address, it is possible to communicate without being conscious of whether the other party is using IPv4 or IPv6 as a communication protocol.

In addition, the registration and deletion of entries in the conversion table between the IPv4 address and the IPv6 address are restricted by the setting of the administrator, so that
It can also be a firewall between the Pv4 and IPv6 networks.

Further, even if no special setting is made in advance,
Communication between two IPv6 terminals separated by the Pv4 network can be performed. Similarly, communication between two IPv4 terminals separated by an IPv6 network can be performed without performing special settings in advance.

Further, even if no special settings are made in advance,
Communication between IPv4 terminals separated by a plurality of IPv4 networks and IPv6 networks, communication between IPv6 terminals, and communication between IPv4 terminals and IPv6 terminals can be performed.

[Brief description of the drawings]

FIG. 1 shows an IPv4-IP according to a first embodiment of the present invention.
It is a block diagram of a v6 converter.

FIG. 2 is a configuration diagram of an IP address conversion table.

FIG. 3 is a configuration diagram of a communication network system according to the first embodiment of the present invention.

FIG. 4 is an IPv4-IP according to the first embodiment of the present invention.
It is a flowchart at the time of starting communication from an IPv4 terminal to an IPv6 terminal via a v6 conversion device.

FIG. 5 is a flowchart continued from FIG. 4;

FIG. 6 is an IPv4-IP according to the first embodiment of the present invention.
It is a flowchart at the time of starting communication from an IPv6 terminal to an IPv4 terminal via a v6 conversion device.

FIG. 7 is a flowchart continued from FIG. 6;

FIG. 8 is an IPv4-IP according to a second embodiment of the present invention.
It is a block diagram of a v6 converter.

FIG. 9 shows an IPv4-IP according to a third embodiment of the present invention.
It is a block diagram of a v6 converter.

FIG. 10 is an IPv4-I according to a fourth embodiment of the present invention.
It is a block diagram of a Pv6 conversion device.

FIG. 11 is a configuration diagram of a communication network system according to a fifth embodiment of the present invention.

FIG. 12 shows an IPv4-I according to a fifth embodiment of the present invention.
It is a flowchart at the time of communicating between IPv6 terminals via a Pv6 conversion apparatus.

FIG. 13 is a continuation of the flowchart of FIG. 12;

[Explanation of symbols]

1, 1a, 1b, 1c, 1d, 111 ... IPv4-IP
v6 converter, 2 ... IPv4 terminal, 3 ... DNSv4 server, 4 ... DHCPv4 server, 5,115 ... IPv6 terminal, 6,116 ... DNSv6 server, 10 ... IP transmitting / receiving means, 11 ... IP header converting means, 13 ... DNS acting Means, 14 ... IPv4 address acquisition means, 15 ... IP address conversion information holding means, 16 ... IPv4 address pool means, 17 ... DHCP server means, 18 ... DNSv4 server means, 19 ... DNSv6 server means, 100, 10
8. Communication network system, 104: IPv4 network, 106, 107: IPv6 network.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Munechika Kadokawa 810 Shimo-Imaizumi, Ebina-shi, Kanagawa Prefecture In-house Systems Division, Hitachi, Ltd. Hitachi, Ltd. Information Systems Division (72) Inventor Takahisa Miyamoto 890 Kashimada, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Hitachi, Ltd.Information Systems Division (72) Shinichi Hamamoto 890 Kashimada, Sai-ku, Kawasaki-shi, Kanagawa Hitachi, Ltd. (72) Inventor Ken Watanabe 890 Kashimada, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Information Systems Division, Hitachi, Ltd.

Claims (14)

[Claims] An IPv4 network, an IPv6 network, and IPv4-IPv6 connected to both of them.
In a communication network system including a conversion device, a method for communicating between an IPv4 terminal of an IPv4 network and an IPv6 terminal of an IPv6 network, wherein: (a) the IPv4 terminal of the IPv4 network is
When inquiring the IPv4-IPv6 translator for the IP address for the domain name of the IPv6 terminal of the network, the IPv4-IPv6 translator will
6 obtains an IPv6 address for the domain name from a DNSv6 server device that manages domain information of 6 networks, and dynamically obtains an IPv4 address corresponding to the IPv6 address from a DHCPv4 server device that dynamically allocates an IPv4 address; The IPv
4 terminal, and the IPv4 terminal notifies its own IPv4 terminal.
IP address as an IPv4 source address and the notified IPv4 address as an IPv4 destination address.
A IPv4 packet is created and sent to the IPv4-IPv6 translator, and (b) the IPv4-IPv6 translator receives the received IPv4 packet.
The fixed data is added to the IPv4 source address included in the four packets to be converted into the IPv6 source address, and
The IP header is converted by an IP header conversion that converts an IPv4 destination address included in the IPv4 packet into an IPv6 destination address using the corresponding IPv6 address.
Create an IPv6 packet from a v4 packet,
(C) The IPv6 terminal creates an IPv6 packet by using its own IPv6 address as an IPv6 source address and an IPv6 source address included in the received IPv6 packet as an IPv6 destination address.
(D) The IPv4-IPv6 translator transmits the received IPv6 to the IPv6 translator.
The fixed data is deleted from the IPv6 destination address included in the IPv6 packet and converted to an IPv4 destination address, and the IPv6 source address included in the IPv6 packet is converted to an IPv6 address using the corresponding IPv4 address.
An IPv4 packet is created from the IPv6 packet by an IP header conversion for converting the IP address into an IPv4 source address.
IPv4 characterized by sending to an IPv4 network
-IPv6 communication method. 2. An IPv4 network, an IPv6 network, and IPv4-IPv6 connected to both of them.
In a communication network system including a conversion device, a method for communicating between an IPv4 terminal of an IPv4 network and an IPv6 terminal of an IPv6 network, wherein: (a) the IPv6 terminal of the IPv6 network is
When the IPv4-IPv6 translator is inquired of the IP address for the domain name of the IPv4 terminal of the network, the IPv4-IPv6 translator receives the IPv4 address.
An IPv4 address corresponding to the domain name is obtained from a DNSv4 server device that manages domain information of the four networks, fixed data is added to the IPv4 address, converted to an IPv6 address, and converted to the IPv6 address.
The IPv6 terminal uses its own IPv6 address as the IPv6 source address and the notified IPv6 address as the IPv6 destination address.
6) creates and sends the packet to the IPv4-IPv6 translator, (b) the IPv4-IPv6 translator translates the received IPv6
DHCP that deletes fixed data from IPv6 destination addresses included in six packets and converts them to IPv4 destination addresses and dynamically allocates IPv4 addresses
I included in the IPv6 packet from the v4 server device
The IPv4 address corresponding to the Pv6 source address is dynamically acquired, and the IPv4 address is converted to an IPv4 source address using the IPv4 address.
(C) The IPv4 terminal sets its own IPv4 address as an IPv4 source address and an IPv4 source address included in the received IPv4 packet as an IPv4 destination address. Is created, and the IPv4-
(D) The IPv4-IPv6 translator transmits the received IPv6 to the IPv6 translator.
The fixed data is added to the IPv4 source address included in the four packets to be converted into the IPv6 source address, and
The IP header is converted by an IP header conversion that converts an IPv4 destination address included in the IPv4 packet into an IPv6 destination address using the corresponding IPv6 address.
Create an IPv6 packet from a v4 packet,
IPv4-I characterized by sending to the network
Pv6 communication method. (A) An IPv4 address corresponding to an IPv6 address of an IPv6 terminal of an IPv6 network is represented by I
IPv4 address acquiring means for acquiring from a DHCPv4 server of a Pv4 network; (b) IPv6 of an IPv6 terminal of an IPv6 network
IP address conversion information holding means for holding an address and an acquired IPv4 address in association with each other; and (c) sending and receiving an IPv4 packet to and from an IPv4 network, and
(d) adding fixed data to an IPv4 source address included in the received IPv4 packet, converting the IPv6 source address into an IPv6 source address, and converting the IPv6 source address into an IPv6 source address.
An IPv6 packet is created from an IPv4 packet by IP header conversion for converting a Pv4 destination address to an IPv6 destination address using a corresponding IPv6 address held in the IP address conversion information holding means, and passed to the IP transmitting / receiving means for transmission. , And the received IP
The fixed data is deleted from the IPv6 destination address included in the v6 packet and converted to the IPv4 destination address, and the IPv6 source address included in the IPv6 packet is used for the corresponding IPv4 address held in the IP address conversion information holding unit. IP header conversion means for generating an IPv4 packet from an IPv6 packet by an IP header conversion for converting the IPv4 packet into an IPv4 transmission address, and passing the packet to the IP transmission / reception means for transmission; and (e) an IPv4 terminal from an IPv4 terminal of the IPv4 network.
Receives an inquiry about an IP address for a domain name of an IPv6 terminal of the IPv6 network, obtains an IPv6 address by inquiring of a DNSv6 server of the IPv6 network, and obtains an IPv4 address corresponding to the IPv6 address.
If the address is held in the IP address conversion information holding means, the IPv4 address is notified to an IPv4 terminal of the IPv4 network, and the IPv4 address corresponding to the IPv6 address must be held in the IP address conversion information holding means. For example, an IPv4 address is acquired by the IPv4 address acquiring means,
The IPv6 address and the acquired IPv4 address are stored in the IP address conversion information storing means in association with each other, and the IPv4 address is stored in the IPv4 network of the IPv4 network.
4 terminals, and an IPv6 terminal in an IPv6 network
It receives an inquiry about the IP address for the domain name of the IPv4 terminal of the 4 network, obtains the IPv4 address by inquiring of the DNSv4 server of the IPv4 network, adds fixed data to the IPv4 address, converts it into an IPv6 address, and converts the IPv6 address. Notifying the IPv6 terminal of the IPv6 network, and further inquiring about the IP address for the domain name of the IPv4 terminal of the IPv4 network.
It is checked whether or not the IPv4 address corresponding to the IPv6 address of the IPv6 terminal of the 6 network is held in the IP address conversion information holding means.
Address, and the IPv6 address and the acquired I
An IPv4-IPv6 conversion device, comprising: a DNS proxy unit for associating a Pv4 address with the IP address conversion information holding unit and holding the same. 4. The IPv4-IPv6 translator according to claim 3, wherein said IP address translation information holding means comprises:
Among the correspondences between the IPv6 addresses and the IPv4 addresses that are held, those that have not been referenced for a certain period of time are deleted, and the deleted IPv4 addresses are replaced with the DHCP of the IPv4 network.
IPv4-IP characterized by returning to a v4 server
v6 converter. 5. IPv4 according to claim 3 or claim 4.
The IPv6 translation device further comprises an IPv4 address pool unit for pooling a plurality of IPv4 addresses, wherein the IP address translation information holding unit is configured to activate the DHCPv
A plurality of IPv4 addresses are obtained from the
Pooled in Pv4 address pool means, IPv6
An IPv4-IPv6 translation device, wherein an IPv4 address corresponding to an IPv6 address of an IPv6 terminal of a network is obtained from the IPv4 address pool means. 6. The IPv4-IPv6 translation apparatus according to claim 3, further comprising: a DHCPv4 server for dynamically allocating an IPv4 address, wherein said DHCPv4 server comprises said IPv4 server.
An IPv4-IPv6 conversion device, which is used in place of a DHCPv4 server of four networks. 7. The IPv4-IPv6 translator according to any one of claims 3 to 6, further comprising: a DNSv4 server for managing domain information of an IPv4 network and a DNSv6 server for managing domain information of an IPv6 network. Equipped, these DNS
v4 server means and DNSv6 server means using the IP
DNSv4 server for IPv4 network and said IPv4
An IPv4-IPv6 conversion device, which is used in place of a DNSv6 server of 6 networks. 8. An IPv4-IPv6 conversion device for mutually converting and relaying an IPv4 packet and an IPv6 packet of communication performed between an IPv4 terminal in an IPv4 network and an IPv6 terminal in an IPv6 network, wherein the IPv4 network comprises: An IP transmitting / receiving means for transmitting / receiving an IPv4 packet and an IPv6 packet to / from the IPv6 network; an IP address conversion information holding means for holding an IPv4 address and an IPv6 address in association with each other; IPv4 to keep
IP address by referring to the correspondence between the address and the IPv6 address
Translates between IPv4 address and IPv6 address,
An IP header conversion unit that converts a 4-packet and an IPv6 packet and then passes the converted packet to the IP transmitting / receiving unit; an IPv4 address obtaining unit that obtains an IPv4 address from a DHCPv4 server in the IPv4 network; Receives an inquiry about an IP address for the domain name of the IPv6 terminal from
An IPv6 address is obtained by inquiring of a DNSv6 server in a Pv6 network, and if an IPv4 address corresponding to the IPv6 address is held in the IP address conversion information holding means, the IPv4 address is notified to the IPv4 terminal, and the IPv6 address is notified. If the IPv4 address corresponding to the address is not held in the IP address conversion information holding means, the IPv4 address is obtained by the IPv4 address obtaining means, and the IPv6 address is associated with the obtained IPv4 address by the I.
The P address translation information holding means holds the IPv4
An IPv4-IPv6 conversion device, comprising: a DNS proxy unit for notifying an address to the IPv4 terminal. 9. The IPv4-IPv6 translator according to claim 8, wherein said IP transmitting / receiving means transmits said IP address from said IPv4 terminal to said IPv4 terminal.
In response to receiving the IPv4 packet sent to the v6 terminal, the received IPv4 packet is passed to the IP header conversion unit, and the IP header conversion unit transmits the IPv4 packet included in the IPv4 packet passed from the IP transmission / reception unit. The fixed address is added to the address and converted to an IPv6 source address, and the IPv4 destination address included in the IPv4 packet is referred to by referring to the association between the IPv4 address and the IPv6 address held by the IP address conversion information holding means. An IPv6 packet is created from the IPv4 packet by an IP header conversion that converts the IPv6 address to an IPv6 destination address using the corresponding IPv6 address, and the IPv6 packet is passed to the IP transmitting / receiving means. Passed An IPv4-IPv6 translation device, wherein the IPv6 packet is transmitted to the IPv6 network. 10. The IPv4-IPv6 translation device according to claim 8, further comprising: an IPv6 address acquisition unit that acquires an IPv6 address from a DHCPv6 server in the IPv6 network, wherein the IP transmission / reception unit receives an IPv6 address from the IPv4 terminal. The IP
In response to receiving the IPv4 packet sent to the v6 terminal, the received IPv4 packet is passed to the IP header conversion unit, and the IP header conversion unit transmits the IPv4 packet included in the IPv4 packet passed from the IP transmission / reception unit. Obtain the source address, and set the IPv6 address corresponding to the IPv4 address.
If the address is held in the IP address conversion information holding means, the IPv6 address is converted to an IPv6 source address using the IPv6 address, and the IP address corresponding to the IPv4 address is converted.
If the Pv6 address is not held in the IP address conversion information holding means, the IPv6 address is obtained by the IPv6 address obtaining means, and the IPv4 address is associated with the obtained IPv6 address and held in the IP address conversion information holding means. And convert the IPv6 address into an IPv6 source address using the IPv6 address.
IPv4 held by the IP address conversion information holding means
With reference to the correspondence between the IPv6 address and the IPv6 address, the IPv4 destination address included in the IPv4 packet is converted into the IPv6 destination address using the corresponding IPv6 address by the IP header conversion.
An IPv6 packet is created from the four packets, and the
6. An IPv4-IPv6 translator, wherein 6 packets are passed to the IP transceiving means, and the IP transceiving means sends out the IPv6 packet passed from the IP header translating means to the IPv6 network. 11. An IPv4 in the IPv4 network.
An IPv4-IPv6 translator for mutually converting and relaying an IPv4 packet and an IPv6 packet of a communication performed between a terminal and an IPv6 terminal in the IPv6 network, wherein the IPv4 packet and the IPv6 packet are transmitted to an IPv4 network and an IPv6 network, respectively. IP transmitting / receiving means for transmitting / receiving an IPv6 packet; IP address conversion information holding means for holding an IPv4 address and an IPv6 address in association with each other; and IPv4 holding by the IP address conversion information holding means.
IP address by referring to the correspondence between the address and the IPv6 address
Translates between IPv4 address and IPv6 address,
An IP header converting means for converting the IP packet into IPv4 packets and then passing the converted data to the IP transmitting / receiving means; and receiving an inquiry about an IP address for a domain name of the IPv4 terminal from the IPv6 terminal,
A DNSv4 server in the Pv4 network is queried to obtain an IPv4 address, add fixed data to the IPv4 address, convert it to an IPv6 address, and
IPv4-IPv4 characterized by comprising a DNS proxy means for notifying a Pv6 address to the IPv6 terminal.
6 conversion device. 12. An IPv4-IPv6 according to claim 11.
The conversion device, further comprising: an IPv4 address obtaining unit that obtains an IPv4 address from a DHCPv4 server in the IPv4 network, wherein the IP transmitting / receiving unit receives the IP from the IPv6 terminal.
In response to receiving the IPv6 packet sent to the v4 terminal, the received IPv6 packet is passed to the IP header conversion unit, and the IP header conversion unit receives the IPv6 packet from the IPv6 packet passed from the IP transmission / reception unit. The fixed data is deleted from the destination address to be converted to an IPv4 destination address, and the IP address included in the passed IPv6 packet is deleted.
A Pv6 source address is obtained, and if the IPv4 address corresponding to the IPv6 address is held in the IP address conversion information holding means, the IPv4 address is converted to an IPv4 source address using the IPv4 address, and the IPv4 address corresponding to the IPv6 address is obtained. If is not held in the IP address conversion information holding means, an IPv4 address is obtained by the IPv4 address obtaining means, and the IPv6 address is held in the IP address conversion information holding means in association with the obtained IPv4 address;
An IPv4 packet is created from an IPv6 packet by an IP header conversion that converts the IPv4 address into an IPv4 source address, and the IPv4 packet is passed to the IP transmitting / receiving means. The IP transmitting / receiving means is passed from the IP header converting means. An IPv4-IPv6 translator for transmitting the IPv4 packet to the IPv4 network. 13. An IPv4 in the IPv4 network.
An IPv4-IPv6 translator for mutually converting and relaying an IPv4 packet and an IPv6 packet of a communication performed between a terminal and an IPv6 terminal in the IPv6 network, wherein the IPv4 packet and the IPv6 packet are transmitted to an IPv4 network and an IPv6 network, respectively. IP transmitting / receiving means for transmitting / receiving an IPv6 packet; IP address conversion information holding means for holding an IPv4 address and an IPv6 address in association with each other; and IPv4 holding by the IP address conversion information holding means.
IP address by referring to the correspondence between the address and the IPv6 address
Translates between IPv4 address and IPv6 address,
An IP header converting means for converting the four packets and the IPv6 packet and then passing the packet to the IP transmitting / receiving means for transmission; an IPv6 address obtaining means for obtaining an IPv6 address from a DHCPv6 server in the IPv6 network; Receiving an inquiry about an IP address for a domain name of an IPv4 terminal,
An IPv4 address is obtained by inquiring of a DNSv4 server in a Pv4 network, and if an IPv6 address corresponding to the IPv4 address is held in the IP address conversion information holding means, the IPv6 address is notified to the IPv6 terminal. If the IPv6 address corresponding to the address is not held in the IP address translation information holding means, the IPv6 address is obtained by the IPv6 address obtaining means, and the IPv4 address is associated with the obtained IPv6 address by the I.
The P address translation information holding means holds the IPv6
An IPv4-IPv6 conversion device, comprising: a DNS proxy unit for notifying an address to the IPv6 terminal. 14. An IPv4-IPv6 according to claim 13.
The conversion device, further comprising: an IPv4 address obtaining unit that obtains an IPv4 address from a DHCPv4 server in the IPv4 network, wherein the IP transmitting / receiving unit receives the IP from the IPv6 terminal.
In response to receiving the IPv6 packet sent to the v4 terminal, the received IPv6 packet is passed to the IP header conversion unit, and the IP header conversion unit stores the IPv4 address and the IPv6 address held by the IP address conversion information holding unit. With reference to the correspondence of the addresses, the IPv6 destination address included in the IPv6 packet is converted into an IPv4 destination address using the corresponding IPv4 address, and the IPv6 source address included in the passed IPv6 packet is acquired. I corresponding to the IPv6 address
If the Pv4 address is held in the IP address conversion information holding means, the IPv4 address using the IPv4 address is used.
If the IPv4 address corresponding to the IPv6 address is not held in the IP address translation information holding means, the IPv4 address is obtained by the IPv4 address obtaining means, and the IPv6 address and the obtained IPv4 address are converted. In the IP address conversion information holding means,
To convert to IPv4 source address using 4 addresses
An IPv4 packet is created from an IPv6 packet by P header conversion, and the IPv4 packet is passed to the IP transmission / reception means. The IP transmission / reception means sends the IPv4 packet passed from the IP header conversion means to the IPv4 network. Characteristic IPv4-IPv6 conversion device.