JP2003188925A - Node and method for transmitting/receiving packet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To combine two networks of different IP address assignment systems due to the difference of versions, etc., without depleting available IP addresses of either network. <P>SOLUTION: A translator 55 is provided with a packet conversion means which assigns any one of multiple IPv4 addresses prepared in advance to an IPv6 address stored in a source address field of the IPv6 packet and stores the IPv4 address in the source address field of the IPv4 packet, when transferring the packet from an IPv6 network 52 to an IPv4 network 54. When transferring the packet from the IPv4 network 54 to the IPv6 network 52, a packet conversion means assigns the aforementioned IPv6 address to the IPv4 address stored in a destination address field of the IPv4 packet, and stores the assigned address in the destination address field of the IPv6 packet. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The first type IP is provided to each of a plurality of target devices so as not to overlap each other.
A first type IP network to which an address is assigned and a second type IP network to which a second type IP address is assigned so as not to overlap with each other for each of a plurality of target devices are targeted. IP network coupling method, IP network translator, and
The present invention relates to a network system using a translator.

[0002]

2. Description of the Related Art At present, the most well-known network layer protocol used in TCP / IP communication is IP (Internet Protocol). The role of IP is to address an OSI (Open Systems Int) such as an addressing service for designating a destination for communication from among nodes connected to the network.
erconnection) This is consistent with the role provided by the third layer of the reference model. At present, version 4 IP (hereinafter referred to as IPv4) is in widespread use. IPv6
The format of the header (hereinafter referred to as the IPv4 header) used in No. 4 is as shown in FIG.

In the IPv4 header, a version number "4" is stored in the "version" field. The “header length” field stores the length of the IPv4 header itself. The “service type” field stores information indicating the service quality of communication processing. In the "packet length" field, the size of the entire packet, in which the IPv4 header is added to the data block handled by IP, is stored. The information received from the upper layer is treated as one data block by IP, and this data block is sent to the lower layer with an IPv4 header added by IP. On the contrary, the IPv4 header included in the packet sent from the lower layer is analyzed by IP, and the data portion of the packet is transferred to the upper layer according to the analysis result. The "identifier" field stores an identifier used as reference information when data is passed to the upper layer. The "flag" field stores control information regarding packet division. The “fragment offset” field stores information indicating where the divided data (fragment) is located in the original data. The "time to live" field stores the time that the packet may exist in the network. The "protocol" field stores information indicating what the upper layer protocol is.
The "header checksum" field stores the checksum of the IP header. "Source IP address"
The IP address of the transmission source is stored in the field.
The IP address of the destination is stored in the "destination IP address" field. The IP address is assigned to each node connected to the network and is set to a different value in the network.

IP having such specifications is rapidly spreading to various communication services at the same time as the spread of the Internet and the like, but on the other hand, it faces a serious problem of exhaustion of IP addresses. is doing.

As a means for solving this, at present,
Version 6 IP (hereinafter referred to as IPv6) has been proposed.

The header used in IPv6 (hereinafter, IPv6
The format of the 6 header) is as shown in FIG. In the IPv6 header, the version number "6" is stored in the "version" field. The “priority” field stores the priority of processing when a router relays a packet in the network. The "flow label" field is used to store an identifier when performing priority control or the like. The "payload length" field stores the length of the data portion of the packet excluding the IPv6 header portion. The "next header identifier" field stores an identifier for identifying which upper layer protocol header follows the IPv6 header, which IPv6 extension header follows, and the like. The "hop limit" field stores the maximum transfer count of the packet. The "source IP address" field stores the source IP address, and the "destination IP address" field stores the destination IP address.
The address is stored. And in the IPv6 header,
Each of the “source IP address” field and the “destination IP address” field is expanded from 32 bits to 128 bits. This increases the number of connectable nodes.

[0007]

[Problems to be Solved by the Invention]
No. 6 is not compatible with the existing IPv4, although the storage area of the IP address has been expanded, but a part of the header and processing has been changed.

In a node newly connected to the network, IPv6 is implemented as a network protocol and an IPv6 address is assigned as a network address. However, it is practically impossible to change the network protocol of existing nodes all together to IPv6. Since it is possible, the period in which the IPv4 node and the IPv6 node coexist is considered to continue for a long time. Also,
For some existing nodes (particularly peripheral devices), it is difficult to change the protocol, and in this case, IPv4 is continuously used.

That is, in the future, it is expected that a network in which a node having IPv6 installed (IPv6 node) and a node having IPv4 installed (IPv4 node) coexist will appear.

However, since IPv6 and IPv4 have different header formats as described above, it is not possible to simply combine the IPv6 node and the IPv4 node.

As one of the solutions, for example, FIG.
There is a connection method using a translator as shown in.

In the figure, an IPv6 node (IPv6
An IPv6 network 52 to which the terminal 10 is connected,
IP to which the IPv4 node (IPv4 terminal) 20 is connected
The v4 network 54 is connected to each other via the translator 30. The IPv4 terminal 20 has an IPv4
An address uniquely assigned within the network 54 (hereinafter referred to as an IPv4 address) is attached,
The IPv6 terminal 10 is provided with both an address uniquely assigned within the IPv6 network 52 (hereinafter referred to as an IPv6 address) and an IPv4 address. The IPv6 terminal 10 uses the IPv6 network 52.
When communicating with another IPv6 terminal (not shown), the self is represented by an IPv6 address, and when communicating with the IPv4 terminal 20 in the IPv4 network 54, the self is represented by an IPv4 address. For example, IPv6
When a packet is sent from the IPv6 terminal 10 to the IPv6 terminal 10, the IPv6 terminal 10 sets its own (IPv6 terminal 10) in the “source IP address” field (see FIG. 11A) when generating the header of the packet to be sent. IPv6
The four addresses are stored in the form as shown in FIG. 12A, and the “destination IP address” field (FIG. 11A) is stored.
12), the IPv4 address of the other party (IPv4 terminal 20) is stored in the form as shown in FIG. 12
In (a), the lower 32 bits of the prepared 128 bits
Bits are used to store address information and other bits are set to '0'. Addresses represented in such a format are generally IPv4-compa.
It is called a table-IPv6 address. Also,
In FIG. 12B, the lower 32 bits of the prepared 128 bits are used for storing the address information, and the 47th to 32nd bits are set to "1" and the other bits are set to "0". ing. Addresses represented in such a format are generally IPv4-mapped-
It is called an IPv6 address. Then, the header in which predetermined information is stored and the data to be sent are sent to the translator 30 as one packet.

The translator 30 converts the received packet into a packet for the IPv4 network 54. Specifically, the above-mentioned IPv4-compatible-IP included in the header of the transmitted packet
From the v6 address, the lower 32 bits, that is, IPv6
The IPv4 addresses of the six terminals 10 are cut out and stored in the “source IP address” field of the IPv4 header shown in FIG. 11B. At the same time, the previous IP included in the header of the sent packet
Lower 32 from v4-mapped-IPv6 address
Bit, that is, I of the IPv4 terminal 20 that is the destination
The Pv4 address is cut out and stored in the “destination IP address” field of the IPv4 header shown in FIG. 11B. After that, other necessary items are set in the header, and the header is sent to the IPv4 terminal 20 as one packet together with the transmission data.

If the above method is used, it is sure that IPv6
A node and an IPv4 node can be interconnected.

However, in this method, it is necessary to assign the IPv4 address to the IPv6 node.

As described above, the number of IPv4 addresses is insufficient, and IPv6 addresses that are used to solve this problem
However, it does not make sense to promote exhaustion of IPv4 addresses.

In view of such a problem, the present invention allows two networks having different IP address assignment systems to differ from each other by the I
(EN) Provided are an IP network joining method capable of joining without depleting P addresses, a translator for an IP network, and a network system using the translator.

[0018]

According to an aspect of an IP network coupling method of the present invention for achieving the above object, it is possible to prevent a plurality of target devices from overlapping with each other. A first type IP network to which one type of IP address is assigned and a second type IP to which a second type IP address is assigned so as not to overlap with each other for each of a plurality of target devices In an IP network connection method for connecting networks by a translator, a target device A which is one of a plurality of target devices existing in the first type IP network,
When starting communication with a target device B, which is one of a plurality of target devices existing in the second type IP network, the second type IP assigned to the target device B
Any of a plurality of first-type IP addresses prepared in advance is assigned to the address, and between the target device B and the translator, the second-type IP address assigned to the target device B is assigned. Communicate using the IP address,
An IP characterized by performing communication between the translator and the target device A using the assigned first type IP address, and releasing the assigned first type IP address after communication is completed. A method of connecting networks is provided.

According to one aspect of the IP network translator of the present invention for achieving the above object, a first type IP address is assigned to each of a plurality of target devices so as not to overlap each other. First type I
In the translator for connecting the P network and the second type IP network to which the second type IP address is assigned to each of the plurality of target devices so as not to overlap with each other, in the translator, A first type IP packet used in the first type IP network and a first type IP packet used in the second type IP network for exchanging information between a network and the second type IP network. Header conversion means for performing header conversion between two types of IP packets, storage means for storing a plurality of first type IP addresses that do not overlap with each other, and the first type IP from the second type IP network. When the header conversion is performed to send the information to the network, it is stored in the source storage area included in the IP header of the second type IP packet. The second type of IP address is, the storage means to the stored in the plurality has a first type of I
One of the P addresses is assigned, the assigned first type IP address is stored in the transmission source storage area included in the IP header of the first type IP packet, and the first type IP address is stored. The first stored in the destination storage area included in the IP header of the first type IP packet during the header conversion performed to send information from the IP network to the second type IP network. The second type stored in the transmission source storage area included in the IP header of the second type IP packet for the second type IP address.
There is provided a translator characterized by allocating a second type IP address and storing the allocated second type IP address in a destination storage area included in an IP header of the second type IP packet.

According to one aspect of the IP network translator of the present invention for achieving the above object, a first type IP address is assigned to each of a plurality of target devices so as not to overlap each other. First type I
A P-network and a second-type IP network to which a second-type IP address is assigned to each of the plurality of target devices so that they do not overlap with each other; A target device A which is one of a plurality of target devices existing in a certain type IP network, wherein the target device A stores a plurality of first type IP addresses that do not overlap each other; When transmitting a first type IP packet containing data to be transmitted to the target device B, which is one of a plurality of target devices existing in two types of IP networks, to the first type network, To the second type IP address given to the target device B, one of the plurality of first type IP addresses stored in the storage means is assigned,
Address conversion means for storing the assigned first type IP address in the destination storage area included in the IP header of the first type IP packet, and the second type assigned to the target device B. A means for sending address translation information including at least an IP address and the first type IP address assigned to the second type IP address to the translator, wherein the translator sends the address translation information from the target device A. Storage means for storing the address conversion information obtained, and the IP address of the first type using the address conversion information.
There is provided a network system comprising a packet conversion means for converting a packet between a network and the second type IP network.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, in the present embodiment, an IPv6 network 52 to which a plurality of IPv6 terminals 51 are connected and an IPv4 to which a plurality of IPv4 terminals 53 are connected.
There are networks 54, these networks are
They are mutually connected via an IPv6 / v4 translator 55 (hereinafter referred to as a translator 55). IP
In the v6 network 52, the IP shown in FIG.
Data transfer is performed by a packet having a v6 header (hereinafter referred to as an IPv6 packet). In the header of the IPv6 packet, the IPv6 terminal 51 indicates that the normal IPv6
The IPv4 terminal 53 is represented by an address
It is represented by the applied-IPv6 address (FIG. 12B). In addition, in the IPv4 network 54, as shown in FIG.
Data transfer is performed by a packet having the IPv4 header shown in (b) (hereinafter referred to as an IPv4 packet). In the header of the IPv4 packet, the translator 55 is represented by an IPv4 address assigned by the translator 55 or a specific IPv4 terminal 53, and the IPv4 terminal 53 is represented by a normal IPv4 address.

As shown in FIG. 2, the translator 55 includes an IPv6 packet flowing in the IPv6 network 52 and an IPv4 / v6 reception processing section 31 for sequentially taking in IPv4 packets flowing in the IPv4 network 54.
The header of the packet captured by the IPv4 / v6 reception processing unit 31 is converted based on the address conversion information stored in the address conversion information table 35, and the contents of the address conversion information table 35 are updated as necessary. An IP that sends the header conversion unit 33 that performs the packet and the packet that has undergone the header conversion process to the destination network.
The address translation information stored in the v4 / v6 transmission processing unit 32 and the address translation information table 35 is transferred to IPv4.
An address translation information exchange unit 34 for exchanging with a specific node connected to the network 54 is provided.

In this embodiment, the IPv4 network 5
There are three types of IPv4 terminals 53 (hereinafter,
Type A, B, C) exist. Type A IP
The v4 terminal 53 is a terminal capable of mounting an application program (hereinafter referred to as an IPv6 application) used in the IPv6 terminal 51, and further possesses the address translation information described above. An outline of the processing performed by the type A IPv4 terminal 53 is shown in FIG. The type C IPv4 terminal 53 is an IPv4 terminal 5
Application program used in 3 (hereinafter, I
Pv4 application), which is a conventional terminal in which the Pv4 application is directly installed. For example, a peripheral device such as a printer corresponds to this. An outline of the processing executed by the type C IPv4 terminal 53 is as shown in FIG. The type B IPv4 terminal 53 is a terminal that has an IPv4 application and owns the above-mentioned address translation information, and its processing outline is as shown in FIG.
The specific node with which the translator 55 exchanges the address translation information is the IPv4 of type A or B among these.
The terminal 53.

The TCP / IPv4 process 81 shown in FIG. 3A corresponds to a general TCP / IP communication process, and here, a service according to IPv4 is performed.
In the TCP / IPv4 process 81, a socket interface (IPv4 socket IF) is used as an interface with the process performed in this upper layer. The IPv6 application process 84 is a process performed by the IPv6 application, and the socket interface (IPv6 socket IF) is used as an interface with the process performed in the lower layer, as in the previous case. Each of the address conversion process 82 and the address conversion information exchange process 83 is interposed between the IPv4 socket IF and the IPv6 socket IF. In the address translation process 82, data transfer including an IP address translation process is performed, and in the address translation information exchange process 83, the address translation information is exchanged between another node (for example, the translator 55) and the IPv4 terminal 53. Will be exchanged.

FIG. 4 shows the internal structure of the type A IPv4 terminal 53.

The TCP / IPv4 process 81 uses TCP / I
The Pv4 reception processing unit 41 and the TCP / IPv4 transmission processing unit 42 are in charge. The address conversion processing unit 82 is in charge of the address conversion processing 82. Address conversion information exchange process 8
3 is handled by the address translation information exchange processing unit 44. In addition, the type A IPv4 terminal 53 is provided with an address translation information table 45.

Next, the IPv6 terminal 51 and the type A I
A packet exchange performed with the Pv4 terminal 53 will be described.

First, packet exchange when communication is started from the IPv6 terminal 51 side will be described with reference to the flowchart of FIG.

Here, the IPv6 address ":: 1234: 567" is sent to the source IPv6 terminal 51 in advance.
8: 9abc ”is assigned, and the destination IPv4
In the terminal 53, the IPv4 address “133.144.9
It is assumed that 5.22 ″ is allocated.

The notation method of the IPv4 address is as follows.

Every 1.8 bits are delimited by "." And expressed in decimal.

Example 123.3.2.1 The notation method of the IPv6 address is as follows.

16 divided by ":" for each 1.16 bits
Expressed in decimal.

Example 1234: 5678: 9abc: de
f0: 0 fed: cba9: 8765: 4321 2. When all 16 bits separated are 0, they may be represented by "::".

Example 1234 :: 9abc: def0: 0
fed: cba9: 8765: 4321 3. All 16 bits separated are 0, and when they are continuous, they may be represented by one "::".

Example 1234 :: 4321 4. When the lower 32 bits include the IPv4 address, the notation method of the IPv4 address can be used for the lower 32 bits.

Example :: ffff: 133.144.9
5.22 When the IPv6 terminal 51 sends the IPv6 packet 56 to the IPv6 network 52 (a1), the IPv6 terminal 51 uses its own IPv6 as the source IP address in the header.
The address ":: 1234: 5678: 9abc" is set and the IPv4 terminal 5 is set as the destination IP address.
3 IPv4-mapped-IPv6 address “::
ffff: 133.144.95.22 "is set.

The IPv4 / v6 reception processing unit 31 of the translator 55 uses the IP that flows through the IPv6 network 52.
v6 packets are sequentially captured, and I is captured each time
The Pv6 packet is a packet in which the IPv4-mapped-IPv6 address is stored in the "destination IP address" field (specifically, the 47th bit to the 32nd bit of the "destination IP address" field are "1").
Is a packet in which all the bits above it are set to "0").
When a corresponding packet is found, it is sent to the header conversion unit 33 (b1). When the header conversion unit 33 receives the packet, the header conversion unit 33 extracts the IPv6 address that is the source IP address included in the packet, and extracts the IPv4 address previously associated with the extracted IPv6 address from the address conversion information table 35. Search from inside (b2). When the target IPv4 address does not exist in the address translation information table 35, the header translation unit 33 adds a certain I to the IPv6 address described above.
Assign a Pv4 address. Here, for the IPv6 address “:: 1234: 5678: 9abc”,
The IPv4 address “192.168.10.3” is assigned (b3). Address conversion information exchange unit 3
4 uses these correspondences as address translation information and I
It is transmitted to the Pv4 terminal 53 (b4). The format of the packet for exchanging the address translation information is as shown in FIG. In this example, “:: 1234: 5678: 9abc” is set in the “IPv6 address” field 101.
Is stored in the “assigned IPv4 address” field 1
“192.168.10.3” is stored in 02.
The "option" field 103 is not particularly used in this embodiment, but can store various control information necessary for communication. Note that the transmission of the address translation information in (b4) is performed not only by the IPv4 terminal 53 that is a communication partner,
All IPv4s that own the address translation information table 45
4 to terminal 53. Further, the header conversion unit 33
The address translation information is stored in the address translation information table 35 (b5).

An example of the structure of the address conversion information table 35 is shown in FIG. Reference numeral 91 is an IPv6 address storage area, 92 is an allocated IPv4 address storage area, and 93 is an option data storage area.
For example, the lines are filled line by line from the top. A plurality of IPv4 addresses to be assigned are prepared in advance, and these are stored in a memory in the translator 55 (not shown). The address conversion information table 35 itself is also stored in this memory.

Since the area where the assigned IPv4 address is used is closed within the IPv4 network, for example, a plurality of IPv4 networks are connected to the IPv6 network 52, and the IPv4 address is assigned to each IPv4 network. Even if they overlap, no problem will occur. That is, when the IPv4 network 54 is an in-company communication network and the IPv6 network is an external communication network using a public line, in the company,
IPv4 used in other companies' IPv4 networks
Addresses may be assigned.

Next, the header conversion unit 33 determines the source IP address in the packet as the IPv6 address ":: 12".
34: 5678: 9abc "to IPv4 address" 1 "
192.168.10.3 ". For the destination IP address, the IPv4 address extracted from the lower 32 bits of the IPv6 address is used. In addition to such address conversion, the header conversion unit 33 uses the IPv6 header. Various processes for converting to an IPv4 header are also executed at the same time (b6), and then the IPv4 / v6 transmission processing unit 32 IP-converts the packet subjected to the conversion process of (b6)
It is sent to the v4 terminal 53. In the search process of (b2), when the corresponding IPv4 address is found, this IPv4 address is adopted as the source IP address, and the processes of (b3), (b4), and (b5) are skipped. To be done.

On the other hand, when the IPv4 terminal 53 receives the address translation information sent from the translator 55 (c1), it updates the contents of the address translation information table 45 using this address translation information (c2). As a result, the address translation information table 3 of the translator 55
5 matches the content of the address translation information table 45 of the IPv4 terminal 53. Specifically, the content of the address translation information table 45 is updated by the address translation information exchange processing unit 44. The processes of (c1) and (c2) are performed by all the IPv4 terminals including the IPv4 terminal which is the communication partner.

When the IPv4 terminal 53 receives the IPv4 packet sent from the translator 55 (c3), the IPv4 terminal 53 carries out the address translation of this IPv4 packet based on the updated address translation information table 45.

Specifically, TCP / of the IPv4 terminal 53
The IPv4 reception processing unit 41 uses the IPv4 network 54.
TCP / IP reception of the previous IPv4 packet flowing through is sent to the address translation processing unit 43. Upon receiving the packet, the address translation processing unit 43 receives the IPv4 address “19”, which is the source IP address of the packet.
2.168.10.3 "extracted and extracted IPv6
The IPv6 address associated with the four addresses is searched from the address translation information table 45. Since the contents of the address conversion information table 45 are updated in (c2), here, the IPv6 address “:: 12” is used.
34: 5678: 9abc "will be extracted.
The address conversion processing unit 43 uses the IPv6 address “:: 1
234: 5678: 9abc "is set in the packet as the source IP address, and this packet is sent to the IPv6 application. The destination IP address is IPv4.
IPv4-mappe whose address is shown in FIG.
The IPv6 address extended to the d-IPv6 address is used. By performing such address conversion, the IPv6 application can receive each of the source IP address and the destination IP address with the IPv6 address. Since the IPv6 application is an application program developed for IPv6 as described above, it is convenient that the received IP address is represented by the IPv6 address.

The IPv6 application may send a packet to the IPv6 terminal 51 as a response process. In this case, the IPv6 application uses its own IPv6 as the source IP address in the packet to be sent.
4 address "133.144.95.22" is shown in FIG.
The IPv6 address “:: ffff: 13 extended to the IPv4-mapped-IPv6 address shown in (b).
3.144.95.22 "is set and the IPv6 address" :: 12 "of the IPv6 terminal 51 is set as the destination IP address.
34: 5678: 9abc "is set. This packet is passed to the address conversion processing unit 43 and subjected to the address conversion reverse to the above. That is, the address conversion processing unit 43 is set as the destination IP address. IPv6 address ":: 1234: 5678: 9a"
bc ”is the IPv4 address“ 192.168.10.
3 ". For the source IP address, I
IPv4 extracted from lower 32 bits of Pv6 address
Use address. After that, the TCP / IPv4 transmission processing unit 42 sends the packet (IPv4 packet 57: FIG. 1) subjected to the translation processing by the address translation processing unit 43 to the translator 55 (c4).

The IPv4 / v6 reception processing section 31 of the translator 55 uses the IP that flows through the IPv4 network 54.
The v4 packet 57 is fetched (b8) and sent to the header conversion unit 33. Upon receiving the packet, the header conversion unit 33 receives the IPv6, which is the destination IP address of the packet.
Extract 4 addresses "192.168.10.3",
IP associated with the extracted IPv4 address
The v6 address is searched for in the address translation information table 35. Here, the IPv6 address ":: 123"
4: 5678: 9abc "will be extracted (b
9). The header conversion unit 33 then sends the packet with the IPv4 of the IPv4 terminal 53 as the source IP address.
-Mapped-IPv6 address ":: ffff: 1
33.144.95.22 "is set, and the IPv6 address" :: 1234: 5678: 9abc "extracted earlier is set as the destination IP address. Further, the header conversion unit 33 performs such address conversion. In addition, various processes for converting the IPv4 header into the IPv6 header are simultaneously executed (b10).
The / IPv6 transmission processing unit 32 sends the packet subjected to the conversion processing of (b10) to the IPv6 terminal 51 (b11). After that, the IPv6 terminal 51 receives this packet (a2).

Regarding the above-mentioned IPv4 address associated with the IPv6 address, the IPv6 terminal 51 and the I
When a series of communication with the Pv4 terminal 53 is completed,
It should be released. Further, the entry of the address translation information table may be deleted according to a command issued at the time of system management of the network. Further, the time after communication is no longer performed may be stored in the option field of the address translation information table, and the assigned IPv4 address in which the timeout has occurred may be forcibly released at that time.

Next, packet exchange when communication is started from the IPv4 terminal 53 side will be described with reference to the flowchart of FIG.

Here, as in the previous case, the IPv6 terminal 51 is also used.
And the IPv6 address “:: 1234: 5678: 9a
bc ”is assigned to the IPv4 terminal 53 and I
It is assumed that the Pv4 address “133.144.95.22” is assigned.

Then, the IPv6 application of the IPv4 terminal 53 sends the packet to be sent to its own IPv4 address "133.144.
95.22 "is set and IP is set as the destination IP address.
IPv6 address of v6 terminal 51 “:: 1234: 56
78: 9abc "is set. This packet is passed to the address translation processing unit 43. Address translation processing unit 4
3 receives the packet, extracts the IPv6 address that is the destination IP address included in the packet, and extracts the IPv4 address previously associated with the extracted IPv6 address from the address translation information table 4
Search from 5 (c1). If the target IPv4 address does not exist in the address translation information table 45, the address translation processing unit 43 assigns a certain IPv4 address to the above-mentioned IPv6 address. Here, the IPv6 address “:: 1234: 5678:
9abc ”for IPv4 address“ 192.16 ”
8.10.3 ″ is allocated (c2). The address translation processing unit 43 sends the correspondence relationship between them to the translator 55 as address translation information (c2).
3). The format of the packet for exchanging the address translation information is as shown in FIG. Further, the address conversion processing unit 43 stores this address conversion information in the address conversion information table 45 (c4). A configuration example of the address conversion information table 45 is shown in FIG. A plurality of IPv4 addresses to be assigned are prepared in advance, and these are stored in the memory of the IPv4 terminal 53 (not shown). The address conversion information table 45 itself is also stored in this memory. After that, the address translation processing unit 43 replaces the IPv6 address “:: 1234: 5678: 9abc” in the packet with the IPv4 address “192.168.10.3”. The source IP address is left unchanged. In addition to such address conversion, the address conversion processing unit 43 also simultaneously executes various processes for converting an IPv6 header into an IPv4 header (c5). Then T
The CP / IPv4 transmission processing unit 42 sends the packet (IPv4 packet 57: FIG. 1) subjected to the translation processing by the address translation processing unit 43 to the translator 55 (c6). In the search process of (c1), when a corresponding IPv4 address is found, this IPv4 address is adopted as the source IP address, and (c
2), (c3) and (c4) are skipped.

On the other hand, when the translator 55 receives the address translation information sent from the IPv4 terminal 53 (b1), it updates the contents of the address translation information table 35 using this address translation information (b2). Accordingly, the address translation information table 45 of the IPv4 terminal 53
And the contents of the address translation information table 35 of the translator 55 match. Address translation information table 3
Specifically, the update of the contents of 5 is performed by the address translation information exchange unit 34. It should be noted that the transmission of the address translation information in (c3) is not limited to the translator 55, and all the IPv4 terminals 53 that have the address translation information table 45.
For each address conversion information table 45 is updated. In this way, the assigned IPv4 address does not overlap between each IPv4 terminal 53 and the translator.

Then, IPv4 / of the translator 55
The v6 reception processing unit 31 takes in the IPv4 packet 57 flowing through the IPv4 network 54 (b3) and sends it to the header conversion unit 33. Upon receiving the packet, the header conversion unit 33 extracts the IPv4 address “192.168.10.3”, which is the destination IP address of the packet, and converts the IPv6 address associated with the extracted IPv4 address into the address conversion information. Table 3
Find out from 5. Since the contents of the address conversion information table 35 are updated in (b2), here,
IPv6 address “:: 1234: 5678: 9ab
c "will be extracted (b4). Header conversion unit 3
3 then uses the packet as the source IP address in the packet, IPv4-mapped-IP of the IPv4 terminal 53.
v6 address “:: ffff: 133.144.95.
22 "is set, and as the destination IP address,
The IPv6 address extracted earlier ":: 1234: 567
8: 9abc ". Also, the header conversion unit 33.
In addition to such address conversion, the CPU simultaneously executes various processes for converting an IPv4 header into an IPv6 header (b5). The IPv4 / IPv6 transmission processing unit 32
The packet subjected to the conversion process of (b5) is sent to the IPv6 terminal 5
It is sent toward 1 (b6). After that, IPv6 terminal 5
1 receives this packet (a1).

The IPv6 terminal 51 may also send the IPv6 packet 51 to the IPv4 terminal 53 as a response process. In this case, when the IPv6 terminal 51 sends out the IPv6 packet 56 to the IPv6 network 52 (a2), the IPv6 address ":: 1234: 5678: 9a of its own" is set in its header as the source IP address.
bc "is set and I is set as the destination IP address.
IPv4-mapped-IPv6 address of Pv4 terminal 53 ":: ffff: 133.144.95.22"
Set. The IPv6 packet 56 is sent to the IPv4 terminal 53 via the translator 55 (c
7). Processing by the translator 55 ((b7), (b
8), (b9), and b (10) are (b1) and (b1) in FIG.
Since it is the same as (b2), (b6), and (b7), the description will not be repeated here.

The above-mentioned IPv4 address assigned to the IPv6 address may be released in the same manner as described above.

Next, the type B IPv4 terminal 53 will be described.

As described above, the type B IPv4 terminal 53 is a terminal which has an IPv4 application and which has the above-mentioned address translation information. Type B
In the IPv4 terminal 53 of, as shown in FIG.
A P / IPv4 process 81, an address conversion process 82, an address conversion process 83, and an IPv4 application process 85 are executed. IPv4 application processing 8
5 is executed on the TCP / IPv4 process 81 via the IPv4 socket interface as shown in FIG. The hierarchical structure of these is the same as that of the conventional IPv4 terminal 53, and the IPv4 application processing 85
Then, the IP address of the packet sent from the TCP / IPv4 process 81 is received by the IPv4 address. Note that the TCP / IPv4 process 81 uses TCP
The / IPv4 reception processing unit 41 and the TCP / IPv4 transmission processing unit 42 are in charge. The address conversion processing unit 82 is in charge of the address conversion processing 82. The address translation information exchange processing 83 is in charge of the address translation information exchange processing unit 44.

As described above, in the type B IPv4 terminal 53, the application side does not particularly need the IPv6 address.

However, the user may want to know the IPv6 address of the communication partner for confirmation or the like.

Therefore, the IPv4 terminal 53 of type B outputs the IPv6 address of the communication partner on the display screen or the like.

That is, when the address translation processing unit 43 of the IPv4 terminal 53 of type B receives the packet output from the IPv4 application, it extracts the IPv4 address which is the source IP address of the packet,
IP associated with the extracted IPv4 address
The v6 address is searched for in the address conversion information table 45, and this is output to the display screen or the like.

Furthermore, the type B IPv4 terminal 5
In 3, the user can arbitrarily associate the IPv6 address with the IPv4 address, which was automatically performed by the translator or the type A IPv4 terminal.

That is, the address conversion processing section 43 determines the address conversion information table 4 according to the operation contents of the user.
Update 5. For example, when the user responds to the IPv6 address “:: 1234: 5678: 9abc” with I
When the operation of the content such as assigning the Pv4 address “192.168.10.3” is performed, the address conversion information table 45 of FIG. 7 is set to the content as shown in FIG. 7, for example. When the address translation information table 45 is updated, the address translation information exchanging unit 44 packetizes this updated portion (see FIG. 8), and the translator 55
Or any other IP that owns the address translation information table
It is transmitted to the v4 terminal 53. As a result, the contents of the address translation information table 45 of each IPv4 terminal 53 and the contents of the address translation information table 35 of the translator 55 match.

The packet exchange performed between the IPv6 terminal 51 and the type B IPv4 terminal 53 is the same as the flow described above with reference to FIGS. 5 and 6, and is therefore described. Is omitted.

Next, the type C IPv4 terminal 53 will be described.

As described above, the type C IPv4 terminal 53 is a terminal on which the IPv4 application used in the IPv4 terminal 53 is directly installed. The type C terminal 53 includes a terminal in which the IPv4 application is stored in the ROM and the software cannot be changed as it is. In the type C IPv4 terminal 53, as shown in FIG. 3C, the IPv4 application processing 85 is executed on the TCP / IPv4 processing 81 via the IPv4 socket interface. TC
The P / IPv4 processing 81 is handled by the TCP / IPv4 reception processing unit 41 and the TCP / IPv4 transmission processing unit 42.

In the type C IPv4 terminal 53,
Due to its configuration, communication cannot be started from the terminal side, but if communication is started from the other party, there will be no particular problem as described below.

Upon receiving the packet output from the TCP / IPv4 reception processing unit 41, the IPv4 application of the type C IPv4 terminal 51 extracts the source IP address and the destination IP address of the received packet, and the data of the received packet. The specified processing specified by the department is performed. After that, the IPv4 application packs the processing result in a packet if necessary and stores it in the T packet.
It is passed to the CP / IPv4 transmission processing unit 42. At this time, IPv6
The 4 application replaces the extracted destination IP address and source IP address and sets them in the packet. For example, the IPv4 address “133.14” is set in the destination IP address “field” of the received packet.
"4.95.22" is stored, and the IPv4 address "192.168.1" is stored in the source IP address "field".
If 0.3 ”is stored, the IPv4 address“ 192.168..0 ”is set in the destination IP address“ field ”.
10.3 ”is stored and the IPv4 address“ 133.1444.95.2 is set in the source IP address “field”.
2 "is stored. This packet is TCP / IPv4
It is sent to the IPv4 network 54 by the transmission processing unit 42 and delivered to the translator 55.

An embodiment in which the IPv4 network and the IPv6 network are connected by the IPv4 / v6 translator has been described above. The actual hardware of the IPv6 / v4 translator used here is, for example, as shown in FIG. It is configured as shown in a).

This IPv6 / v4 translator uses C
It has a PU 71, a memory 72, and network interfaces 73-1 and 73-2 to 73-n. The CPU 71 manages the memory 72 and controls the network interfaces 73-1 and 73-2 to 73-n. Further, various programs are stored in advance in the memory 72, and these programs can be stored in the CP as needed.
By executing in U71, IPv4 / v shown in FIG.
6 reception processing unit 31, IPv4 / v6 transmission processing unit 32, header conversion unit 33, address conversion information exchange unit 34, and address conversion information table 35.

In FIG. 1, the IPv6 network 5
Since two IPv4 networks 54 and one IPv4 network 54 exist, the network interface 73-1 is used for the IPv6 network 52 and the network interface 73-2 is used for the IPv4 network 54, for example. In this case, the network interface 73-1 takes in the IPv6 packet flowing through the IPv6 network 52 and stores it in the memory 72,
The network interface 73-2 sends the IPv4 packet generated by performing the header conversion and the like to the IPv4 network 54. Even when packets are sent in the reverse direction, each of the network interfaces 73-1 and 73-2 performs the opposite operation. In addition, multiple IPv6
6. If there are IPv4 networks, network interfaces will be used according to the number.

The actual hardware of the IPv4 terminal is configured as shown in FIG. 10 (b), for example.

The IPv4 terminal has a CPU 71, a memory 72, and a network interface 73. The CPU 71 manages the memory 72 and controls the network interface 73. Memory 7
Various programs are stored in advance in 2. For example, in the case of a type A IPv4 terminal, the program in the memory 72 is executed by the CPU 71 as needed, and TCP / TCP /
IPv4 reception processing unit 41, TCP / IPv4 transmission processing unit 42, address conversion processing unit 43, address conversion information exchange processing unit 44, address conversion information table 45, and IPv4.
4 applications are realized. The network interface 73 is an I that flows through the IPv4 network 54.
The Pv4 packet is fetched and stored in the memory 72, and the IPv4 packet generated by performing the address conversion and the like is sent to the IPv4 network 54.

It is also possible to assign an IPv4 address to a specific IPv6 terminal in advance and store this in the address translation information table. In this way, the processing time for allocation is reduced.

The present invention is not limited to the network configuration as shown in FIG. For example, IPv6
The present invention can be applied to a network in which four networks and an IPv6 network are mixed. In FIG. 9, IP
IPv4 in which the v4 terminal 62 and the IPv6 terminal 61 are connected
A / v6 mixed network 64 is shown. IPv4
In the / v6 mixed network 64, the IPv4 packet 6
6 and the IPv6 packet 65 coexist,
The IPv4 / v6 translator 63 captures these in itself, and if necessary for the captured packet,
The address conversion and header conversion described above are performed, and this is returned to the network. In this way, IPv6
Communication between the four terminals 62 and the translator 63 is performed by the IPv4 packet 66, and communication between the translator 63 and the IPv6 terminal 61 is performed by the IPv6 packet 65.

Further, the present invention is not limited to the combination of the IPv4 network and the IPv6 network, and two types of networks (first type IP network) in which the IP address assignment systems are different due to the difference in version, etc. And second type IP network).

[0077]

According to the present invention, the target device A, which is one of a plurality of target devices existing in the first type IP network (for example, IPv4 network), and the second type IP network (for example, , IPv6 network), which is one of the plurality of target devices existing in the IPv6 network)
When a communication is started between the first type IP network and the second type IP network, the translator provided between the first type IP network and the second type IP network, or the target device A is assigned to the target device B. The first type IP address is assigned to the two types of IP addresses, and in the first type IP network, communication is performed using the first type IP address.

Therefore, in order to communicate with the target device A of the first type IP network, the waste of pre-assigning the first type IP address to the target device B existing in the second type IP network. Address settings are eliminated, and scarce type 1 IP addresses are effectively used.

The first type I assigned to the target device A
Since the P address is closed and used in the first type IP network, there is no problem even if the same IP address is used in the external network, and the first type IP address can be used more effectively. You can

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of a network to which the present invention is applied.

2 is an IPv4 / v used in the network of FIG. 1;
The block diagram which showed the function of the 6 translator.

3A is an explanatory diagram showing an outline of processing performed by an IPv4 terminal of type A connected to the network of FIG. FIG. 3B is an explanatory view showing an outline of processing performed by the type B IPv4 terminal connected to the network of FIG. FIG. 3C: An explanatory diagram showing an outline of processing performed by the type C IPv4 terminal connected to the network of FIG.

4 is a Type A I connected to the network of FIG.
The block diagram which showed the function of the Pv4 terminal.

5 is an IPv6 terminal in the network of FIG.
The flowchart which showed the communication procedure (the 1) between IPv4 terminals.

6 is an IPv6 terminal in the network of FIG.
The flowchart which showed the communication procedure (the 2) between IPv4 terminals.

7 is a type A, B connected to the network of FIG.
Explanatory diagram showing an example of an address translation information table provided in each of the IPv4 terminal and the IPv4 / v6 translator of FIG.

8 is an explanatory diagram showing a format of a packet for transmitting the storage information of the address translation information table of FIG.

FIG. 9 is a configuration diagram showing another example of a network to which the present invention is applied.

FIG. 10A is a configuration diagram showing an example of a hardware configuration of an IPv4 / v6 translator connected to a network to which the present invention is applied. FIG. 10B is a configuration diagram showing an example of a hardware configuration of an IPv4 terminal connected to a network to which the present invention is applied.

FIG. 11A is an explanatory diagram of a format of an IPv6 header. FIG. 11B: An explanatory diagram of the format of the IPv4 header.

FIG. 12 (a): IPv4-compatib
Explanatory drawing of the format of le-IPv6 address. FIG. 12B: An explanatory diagram of the format of the IPv4-mapped-IPv6 address.

FIG. 13 is an explanatory diagram showing a method for connecting an IPv4 network and an IPv6 network.

[Explanation of sign]

31: IPv4 / v6 reception processing unit, 32: IPv4 /
v6 transmission processing unit, 33: header conversion unit, 34: address conversion information exchange unit, 35: address conversion information table, 41: TCP / IPv4 reception processing unit, 42: T
CP / IPv4 transmission processing unit, 43: address conversion processing unit, 44: address conversion information exchange processing unit, 45: address conversion information table, 51, 61: IPv6 terminal, 52: IPv6 network, 53, 62: I
Pv4 terminal, 54: IPv4 network, 55,
63: IPv4 / v6 translator, 56, 65:
IPv6 packet, 57, 66: IPv4 packet,
64: IPv6 / v4 mixed network, 71: C
PU, 72: memory, 73: network interface, 81: TCP / IPv4 processing, 82: address conversion processing, 83: address conversion information exchange processing,
84: IPv6 application, 85: IPv4 application, 91, 101: IPv6 address field, 92, 102: assigned IPv4 address field, 93, 103: option field

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuaki Tsuchiya             890 Kashimada, Sachi-ku, Kawasaki City, Kanagawa Stock             Hitachi, Ltd. Information & Communication Development Division (72) Inventor Naoya Ikeda             810 Shimo-Imaizumi Stock Exchange, Ebina City, Kanagawa Prefecture             Hitachi, Ltd. Office Systems Division F-term (reference) 5K030 HA08 HB18 HD01 HD09 KA05                       LA08 LB15

Claims (20)

[Claims] 1. A node connected to a network for transmitting and receiving packets to and from the network, executing a storage unit for storing an IPv6 application program, executing the IPv6 application program stored in the storage unit, and transmitting an IPv6 header. And a processing unit for generating an IPv6 packet including the IPv6 packet, and an arbitrary I to the IPv6 address stored as the destination address in the IPv6 header of the IPv6 packet.
A Pv4 address is allocated, the IPv6 header is stored as the destination address, the arbitrary IPv4 address is stored, and a conversion unit that converts the IPv6 header into an IPv4 header having a different header format from the IPv6 header to generate an IPv4 packet, and the IPv4 packet A transmission unit that transmits to the network. 2. The node according to claim 1, further comprising a holding unit that holds a plurality of IPv4 addresses, and the conversion unit includes the plurality of IPv4 held in the holding unit.
A node characterized by assigning any one of four addresses to the IPv6 address. 3. The node according to claim 1, wherein the I
A node further comprising a second storage unit that stores a Pv6 address and the assigned arbitrary IPv4 address in association with each other. 4. A node connected to a network for transmitting and receiving packets to and from the network, executing a first storage unit for storing an IPv6 application program, and executing an IPv6 application program stored in the storage unit, A processing unit that generates an IPv6 packet including an IPv6 header, a second storage unit that stores an IPv6 address and an IPv4 address in association with each other, and an IPv6 address stored as a destination address in the IPv6 header of the IPv6 packet. The IPv4 address that is associated and stored in the second storage unit is extracted from the second storage unit, the IPv6 header is stored as the destination address, and the IPv4 address is stored. The IPv6 header is a header format. Different IPv4 A node comprising: a conversion unit that converts an IPv4 packet into a header to generate an IPv4 packet; and a transmission unit that transmits the IPv4 packet to the network. 5. The node according to claim 4, further comprising a third storage unit that holds a plurality of IPv4 addresses,
The conversion unit uses any one of the plurality of IPv4 addresses held in the third storage unit as the IP address.
A node characterized by being stored in the second storage unit in association with a v6 address. 6. The node according to claim 1 or 4, wherein the conversion unit stores a second IPv4 address assigned to the node itself by using the IPv6 header as a source address. A node characterized by converting to an IPv4 header. 7. The node according to claim 1 or 4, wherein the conversion unit stores an IPv4-mapped-in which is stored in the IPv6 header as a source address.
An IPv6 address is converted into a second IPv4 address assigned to the node itself, and the IPv6 header is converted into an IPv4 header in which the second IPv4 address is stored as a source address. node. 8. The node according to claim 3 or 4, further comprising a receiving unit that receives an IPv4 packet from the network, and when the receiving unit receives an IPv4 packet, the converting unit causes the receiving unit to receive the IPv4 packet. The second IPv6 address stored in association with the second IPv4 address stored as the source address in the IPv4 header of the IPv4 packet is extracted from the second storage unit, and the IPv4 header is transmitted. IPv6 in which the second IPv6 address is stored as the original address
A node characterized by converting to a header. 9. The node according to claim 8, wherein the conversion unit stores a third IPv4 address assigned to the node itself, which is stored as a destination address in the IPv4 header, in the lower 32 bits. Third IP
translates to a third IPv6 address, including a v4 address,
A node, which converts the IPv4 header into an IPv6 header in which the third IPv6 address is stored as a destination address. 10. The node according to claim 8, wherein the conversion unit is a third node assigned to the node itself stored as a destination address in the IPv4 header.
Of the IPv4 address of the I4 as a destination address by converting the IPv4 address of the IPv4 address into an IPv4-mapped-IPv6 address including the third IPv4 address.
Pv4-mapped-IPv6 address A node characterized by converting to an IPv6 header in which an address is stored. 11. A packet transmission / reception method in a node connected to a network, wherein an IPv6 application program is executed and an IPv6 header is included.
6 packets, and the IP of the IPv6 packet
IPv6 stored as the destination address in the v6 header
6 addresses are assigned arbitrary IPv4 addresses, and the IPv6 header is used as a destination address for the arbitrary IP
The v4 address is stored and converted into an IPv4 header having a different header format from the IPv6 header, and the data included in the IPv6 packet and the IPv4 header are converted.
A packet transmission / reception method comprising generating an IPv4 packet from a header and transmitting the IPv4 packet to the network. 12. The packet transmission / reception method according to claim 11, wherein a plurality of IPv4 addresses are held in advance, and any one of the held plurality of IPv4 addresses is assigned to the IPv6 address. Characteristic packet transmission / reception method. 13. The packet transmission / reception method according to claim 11, wherein the IPv6 address and the assigned arbitrary IPv4 address are stored in association with each other. 14. A packet transmission / reception method in a node connected to a network, comprising an IPv6 address and an I
Pv4 address is stored in association with the IPv6 address, the IPv6 application program is executed, an IPv6 packet including an IPv6 header is generated, and the IPv6 packet is stored in association with the IPv6 address stored as the destination address in the IPv6 header. IPv6
4 addresses are extracted, and the IPv4 address is stored with the IPv6 header as the destination address.
A packet transmission / reception, characterized in that an IPv4 header having a different header format from a v6 header is converted, an IPv4 packet is generated from the data included in the IPv6 packet and the IPv4 header, and the IPv4 packet is transmitted to the network. Method. 15. The packet transmitting / receiving method according to claim 14, wherein a plurality of IPv4 addresses are held in advance, and any one of the plurality of IPv4 addresses is transferred to the IP.
A packet transmission / reception method characterized by storing in association with a v6 address. 16. The packet transmitting / receiving method according to claim 11 or 14, wherein the IPv6 header is stored in an IPv4 header storing a second IPv4 address assigned to the node itself as a source address. A packet transmission / reception method characterized by converting. 17. The packet transmitting / receiving method according to claim 11 or 14, wherein IPv4-mappe stored as a source address in the IPv6 header.
The d-IPv6 address is converted into a second IPv4 address assigned to the node itself, and the IPv6
A packet transmitting / receiving method comprising: converting a header into an IPv4 header in which the second IPv4 address is stored as a source address. 18. The packet transmission / reception method according to claim 13 or 14, wherein the IP is transmitted from the network.
When the v4 packet is received, the second IPv6 address stored in association with the second IPv4 address stored as the source address in the IPv4 header of the received IPv4 packet is extracted, and the IPv4 header is A packet transmission / reception method characterized by converting to an IPv6 header in which the second IPv6 address is stored as a source address. 19. The packet transmission / reception method according to claim 18, wherein a third address assigned to the node itself is stored in the IPv4 header as a destination address.
IPv4 address of the third I
A packet transmitting / receiving method comprising: converting to a third IPv6 address including a Pv4 address, and converting the IPv4 header into an IPv6 header in which the third IPv6 address is stored as a destination address. 20. The packet transmission / reception method according to claim 18, wherein a third address assigned to the node itself is stored in the IPv4 header as a destination address.
IPv4-address of IPv4-mapped-IP
A packet transmission / reception method comprising converting to a v6 address and converting the IPv4 header into an IPv6 header in which the IPv4-mapped-IPv6 address is stored as a destination address.