JP3791496B2 - Packet transmission / reception node and packet transmission / reception method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
Each of a plurality of target devices overlaps each of a plurality of target devices and a first type IP network to which a first type IP address is assigned so as not to overlap each other. The present invention relates to an IP network coupling method for a second type IP network to which a second type IP address is assigned so that there is no problem, an IP network translator, and a network system using the translator.
[0002]
[Prior art]
The most well-known network layer protocol used in TCP / IP communication is IP (Internet Protocol). The role of IP coincides with the role provided by the third layer of the OSI (Open Systems Interconnection) reference model, such as an addressing service for designating a destination for communication among nodes connected to the network. At present, version 4 IP (hereinafter referred to as IPv4) is widespread. The format of a header (hereinafter referred to as IPv4 header) used in IPv4 is as shown in FIG.
[0003]
In the IPv4 header, “4” which is a version number 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 service quality of communication processing. The “packet length” field stores the size of the entire packet obtained by adding the IPv4 header to a data block handled by IP. The information coming from the upper layer is handled as one data block by IP, and this data block is sent to the lower layer with an IPv4 header added by IP. Conversely, the IPv4 header included in the packet sent from the lower layer is analyzed by IP, and the data portion of the packet is raised to the upper layer according to the analysis result. The “identifier” field stores an identifier used as reference information when data is transferred to the upper layer. The “flag” field stores control information related to 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 during which 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. The “source IP address” field stores the source IP address. The “destination IP address” field stores the IP address of the destination. The IP address is assigned to each node connected to the network, and is set to a different value in the network.
[0004]
IP with such specifications is now rapidly spreading to various communication services in line with the spread of the Internet, etc., but on the other hand, it faces a serious problem of IP address exhaustion. .
[0005]
As means for solving this problem, version 6 IP (hereinafter referred to as IPv6) has been proposed.
[0006]
The format of a header (hereinafter referred to as IPv6 header) used in IPv6 is as shown in FIG. In the IPv6 header, “6” which is a version number is stored in the “version” field. The “priority” field stores the priority of processing when the 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 excluding the IPv6 header portion from the packet. In the “next header identifier” field, an identifier for identifying which upper layer protocol header follows the IPv6 header or which IPv6 extension header follows is stored. 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. 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]
However, although the IPv6 storage area has been expanded, IPv6 is not compatible with the existing IPv4 because of changes to the header and part of the processing.
[0008]
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 simultaneously change the network protocol of existing nodes to IPv6. Therefore, it is considered that the period in which the IPv4 node and the IPv6 node coexist lasts for a long time. Some of the existing nodes (particularly peripheral devices) may be difficult to change the protocol. In this case, IPv4 is used as it is.
[0009]
That is, in the future, it seems that a network in which a node in which IPv6 is implemented (IPv6 node) and a node in which IPv4 is implemented (IPv4 node) coexists will appear.
[0010]
However, since IPv6 and IPv4 have different header formats and the like as described above, IPv6 nodes and IPv4 nodes cannot be simply combined.
[0011]
One solution is, for example, a connection method using a translator as shown in FIG.
[0012]
In the figure, an IPv6 network 52 to which an IPv6 node (IPv6 terminal) 10 is connected and an IPv4 network 54 to which an IPv4 node (IPv4 terminal) 20 is connected are connected to each other via a translator 30. The IPv4 terminal 20 is assigned an address uniquely assigned within the IPv4 network 54 (hereinafter referred to as an IPv4 address), and the IPv6 terminal 10 is assigned an address uniquely assigned within the IPv6 network 52 (hereinafter referred to as “IPv4 address”). , Called an IPv6 address) and an IPv4 address. When the IPv6 terminal 10 communicates with another IPv6 terminal (not shown) within the IPv6 network 52, the IPv6 terminal 10 represents itself with an IPv6 address, and when communicating with the IPv4 terminal 20 within the IPv4 network 54, , Represents itself with an IPv4 address. For example, when sending a packet from the IPv6 terminal 10 to the IPv4 terminal 20, the IPv6 terminal 10 sets itself (IPv6 terminal 10) in the “source IP address” field (see FIG. 11A) when generating the header of the packet to be sent. ) Is stored in the form as shown in FIG. 12A, and the IPv4 address of the partner (IPv4 terminal 20) is stored in the “destination IP address” field (see FIG. 11A). Store in the form shown in. In FIG. 12A, the lower 32 bits of the prepared 128 bits are used for storing address information, and the other bits are set to '0'. An address represented in such a format is generally called an IPv4-compatible-IPv6 address. In FIG. 12B, the lower 32 bits of the prepared 128 bits are used for storing address information, the 47th to 32nd bits are set to “1”, and the other bits are set to “0”. It is set. An address represented in such a format is generally called an IPv4-mapped-IPv6 address. The header storing the predetermined information and the data to be sent are sent to the translator 30 as one packet.
[0013]
The translator 30 converts the received packet into a packet for the IPv4 network 54. Specifically, the lower 32 bits, that is, the IPv4 address of the IPv6 terminal 10 is cut out from the previous IPv4-compatible-IPv6 address included in the header of the sent packet, and this is shown in FIG. ) In the “source IP address” field of the IPv4 header shown in FIG. At the same time, the lower 32 bits, that is, the IPv4 address of the IPv4 terminal 20 that is the destination, is cut out from the previous IPv4-mapped-IPv6 address included in the header of the sent packet, It is stored in the “destination IP address” field of the IPv4 header shown in FIG. Thereafter, other necessary items are set in this header, and are sent to the IPv4 terminal 20 as one packet together with the transmission data.
[0014]
If the above method is used, the IPv6 node and the IPv4 node can be connected to each other.
[0015]
However, in this method, it is necessary to assign an IPv4 address to the IPv6 node.
[0016]
As described above, the number of IPv4 addresses is insufficient, and it is meaningless if IPv6 made to solve this problem promotes the exhaustion of IPv4 addresses.
[0017]
In view of such problems, the present invention is capable of combining two networks having different IP address assignment systems due to version differences or the like without exhausting the IP address of one network. Coupling method, IP network translator, and network system using the translator are provided.
[0018]
[Means for Solving the Problems]
According to one aspect of the IP network coupling method of the present invention for achieving the above object,
Each of a plurality of target devices overlaps each of a plurality of target devices and a first type IP network to which a first type IP address is assigned so as not to overlap each other. In the IP network connection method for connecting the second type IP network to which the second type IP address is assigned by a translator so that there is no
A target device A that is one of a plurality of target devices that exist in the first type IP network and a target device B that is one of a plurality of target devices that exist in the second type IP network. Assigning one of a plurality of first type IP addresses prepared in advance to the second type IP address assigned to the target device B,
Between the target device B and the translator, communication is performed using the second type IP address assigned to the target device B, and the allocated between the translator and the target device A Communicate using the first type of IP address,
An IP network coupling method is provided in which the assigned first type IP address is released after communication is completed.
[0019]
According to one aspect of the IP network translator of the present invention to achieve the above object,
Each of a plurality of target devices overlaps each of a plurality of target devices and a first type IP network to which a first type IP address is assigned so as not to overlap each other. In the translator that joins the second type IP network to which the second type IP address is assigned so that there is no
In order to exchange information between the first type IP network and the second type IP network, the first type IP packet and the second type IP used in the first type IP network. Header conversion means for performing header conversion with the second type IP packet used in the network;
Storage means for storing a plurality of first type IP addresses that do not overlap each other;
In the header conversion performed to send information from the second type IP network to the first type IP network, the source storage area included in the IP header of the second type IP packet Any one of a plurality of first type IP addresses stored in the storage means is assigned to the stored second type IP address, and the assigned first type IP address is assigned to the first type IP address. Storing it in the source storage area included in the IP header of one type of IP packet; and
Stored in the destination storage area included in the IP header of the first type IP packet at the time of header conversion performed to send information from the first type IP network to the second type IP network The second type IP address stored in the transmission source storage area included in the IP header of the second type IP packet is assigned to the first type IP address being assigned, A translator is provided that stores two types of IP addresses in a destination storage area included in an IP header of the second type IP packet.
[0020]
According to one aspect of the IP network translator of the present invention for achieving the above object, the first type IP address is assigned to each of a plurality of target devices so as not to overlap each other. A translator for mutually coupling one type of IP network and a second type of IP network to which a second type of IP address is assigned so as not to overlap each other for each of a plurality of target devices;
A target device A that is one of a plurality of target devices existing in the first type IP network;
The target device A is
Storage means for storing a plurality of first type IP addresses that do not overlap each other;
When sending a first type IP packet including data to be transmitted to the target device B, which is one of a plurality of target devices existing in the second type IP network, to the first type network. Any one of the plurality of first type IP addresses stored in the storage unit is assigned to the second type IP address assigned to the target device B, and the assigned first type IP address is assigned. Address conversion means for storing an IP address in a destination storage area included in an IP header of the first type IP packet;
Means for sending address translation information including at least the second type IP address assigned to the target device B and the first type IP address assigned to the second type IP address to the translator And
The translator is
Storage means for storing address conversion information sent from the target device A;
There is provided a network system comprising packet conversion means for performing packet conversion between the first type IP network and the second type IP network using the address conversion information.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0022]
As shown in FIG. 1, in this embodiment, there is an IPv6 network 52 to which a plurality of IPv6 terminals 51 are connected, and an IPv4 network 54 to which a plurality of IPv4 terminals 53 are connected. These networks are IPv6 / v4. They are connected to each other via a translator 55 (hereinafter referred to as a translator 55). In the IPv6 network 52, data transfer is performed using a packet having an IPv6 header (hereinafter referred to as an IPv6 packet) shown in FIG. In the IPv6 packet header, the IPv6 terminal 51 is represented by a normal IPv6 address, and the IPv4 terminal 53 is represented by an IPv4-mapped-IPv6 address (FIG. 12B). In the IPv4 network 54, data transfer is performed using a packet having an IPv4 header shown in FIG. 11B (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.
[0023]
As shown in FIG. 2, the translator 55 receives the IPv6 packet flowing in the IPv6 network 52, the IPv4 / v6 reception processing unit 31 that sequentially captures the IPv4 packet flowing in the IPv4 network 54, and the packet captured by the IPv4 / v6 reception processing unit 31. The header conversion unit 33 that converts the header of the address conversion information based on the address conversion information stored in the address conversion information table 35 and updates the contents of the address conversion information table 35 as necessary, and header conversion processing The IPv4 / v6 transmission processing unit 32 that sends the received packet to the destination network and the address translation information stored in the address translation information table 35 are exchanged with a specific node connected to the IPv4 network 54 Address translation information exchange unit 34 Equipped with a.
[0024]
In the present embodiment, there are three types (hereinafter referred to as types A, B, and C) of the IPv4 terminal 53 connected to the IPv4 network 54. The type A IPv4 terminal 53 can be loaded with 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 processing performed in the type A IPv4 terminal 53 is shown in FIG. The type C IPv4 terminal 53 is a conventional terminal in which an application program (hereinafter referred to as an IPv4 application) used in the IPv4 terminal 53 is directly installed. For example, a peripheral device such as a printer corresponds to this. The 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 is equipped with an IPv4 application and possesses the address translation information described above, and its processing outline is as shown in FIG. The specific nodes with which the translator 55 exchanges address translation information are the type A and B IPv4 terminals 53.
[0025]
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 processing 81, a socket interface (IPv4 socket IF) is used as an interface with processing performed at the higher level. The IPv6 application process 84 is a process performed by the IPv6 application, and a socket interface (IPv6 socket IF) is used as an interface with a process performed at a lower level as in the previous case. Each of the address translation process 82 and the address translation 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, address translation information is transmitted between the other nodes (for example, the translator 55) and the IPv4 terminal 53. Is exchanged.
[0026]
FIG. 4 shows the internal configuration of a type A IPv4 terminal 53.
[0027]
The TCP / IPv4 processing 81 is handled by the TCP / IPv4 reception processing unit 41 and the TCP / IPv4 transmission processing unit 42. The address conversion processing unit 43 is in charge of the address conversion processing 82. The address translation information exchange processing 83 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.
[0028]
Next, packet exchange performed between the IPv6 terminal 51 and the type A IPv4 terminal 53 will be described.
[0029]
First, packet exchange when communication is started from the IPv6 terminal 51 side will be described with reference to the flowchart of FIG.
[0030]
Here, the IPv6 address “:: 1234: 5678: 9abc” is assigned to the source IPv6 terminal 51 in advance, and the IPv4 address “133.144.95.22” is assigned to the destination IPv4 terminal 53 in advance. It is assumed that
[0031]
The notation method of the IPv4 address is as follows.
[0032]
Each decimal bit is represented by a decimal number separated by “.”.
[0033]
Example. 123.3.2.1
The notation method of the IPv6 address is as follows.
[0034]
1. Each 16-bit is separated by “:” and expressed in hexadecimal.
[0035]
Example. 1234: 5678: 9abc: def0: 0 fed: cba9: 8765: 4321
2. When all 16 bits delimited are 0, they may be represented by “::”.
[0036]
Example. 1234 :: 9abc: def0: 0 fed: cba9: 8765: 4321
3. If all 16 bits delimited are 0 and they are continuous, they may be represented by one “::”.
[0037]
Example. 1234 :: 4321
4). When the lower 32 bits include an IPv4 address, the IPv4 address notation method can be used for the lower 32 bits.
[0038]
Example. :: ffff: 133.144.95.22
When the IPv6 terminal 51 sends out the IPv6 packet 56 to the IPv6 network 52 (a1), it sets its own IPv6 address “:: 1234: 5678: 9abc” as the source IP address in the header. The IPv4-mapped-IPv6 address “:: ffff: 133.144.95.22” of the IPv4 terminal 53 is set as the destination IP address.
[0039]
The IPv4 / v6 reception processing unit 31 of the translator 55 sequentially fetches IPv6 packets flowing through the IPv6 network 52, and each time the fetched IPv6 packet has an IPv4-mapped-IPv6 address stored in the “destination IP address” field. Packet (specifically, a packet in which the 47th to 32nd bits of the “destination IP address” field are set to “1” and all the higher bits are set to “0”). Determine whether or not. If 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 an IPv6 address that is a transmission source IP address included in the packet, and an IPv4 address previously associated with the extracted IPv6 address is extracted from the address conversion information table 35. (B2). If the target IPv4 address does not exist in the address translation information table 35, the header translation unit 33 assigns a certain IPv4 address to the IPv6 address described above. Here, the IPv4 address “192.168.10.3” is assigned to the IPv6 address “:: 1234: 5678: 9abc” (b3). The address translation information exchange unit 34 transmits these correspondences as address translation information to the IPv4 terminal 53 (b4). The format of a packet for exchanging address translation information is as shown in FIG. In this example, “:: 1234: 5678: 9abc” is stored in the “IPv6 address” field 101, and “192.168.10.3” is stored in the “assigned IPv4 address” field 102. The “option” field 103 is not particularly used in the present embodiment, but can store various control information necessary for communication. Note that the transmission of the address translation information (b4) is performed not only to the IPv4 terminal 53 that is the communication partner but also to all IPv4 terminals 53 that own the address translation information table 45. The header conversion unit 33 stores the address conversion information in the address conversion information table 35 (b5).
[0040]
A configuration example of the address conversion information table 35 is shown in FIG. 91 is a storage area for IPv6 addresses, 92 is a storage area for allocated IPv4 addresses, and 93 is a storage area for option data. For example, one line is filled in order from the top. A plurality of IPv4 addresses to be allocated 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.
[0041]
In addition, since the area where the allocated IPv4 address is used is closed in the IPv4 network, for example, a plurality of IPv4 networks are connected to the IPv6 network 52, and the IPv4 addresses overlap in each IPv4 network. However, no problem occurs. 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, the company may assign an IPv4 address used in the IPv4 network of another company.
[0042]
Subsequently, the header conversion unit 33 replaces the source IP address in the packet with the IPv4 address “192.168.10.3” from the IPv6 address “:: 1234: 5678: 9abc”. 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 simultaneously executes various processes for converting an IPv6 header into an IPv4 header (b6). Subsequently, the IPv4 / v6 transmission processing unit 32 sends the packet that has undergone the conversion process of (b6) to the IPv4 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. Is done.
[0043]
On the other hand, when receiving the address translation information sent from the translator 55 (c1), the IPv4 terminal 53 updates the contents of the address translation information table 45 using this address translation information (c2). As a result, the contents of the address translation information table 35 of the translator 55 match the contents of the address translation information table 45 of the IPv4 terminal 53. Specifically, the address translation information table 45 is updated by the address translation information exchange processing unit 44. The processes (c1) and (c2) are performed in all IPv4 terminals including the IPv4 terminal that is the communication partner.
[0044]
Further, when the IPv4 terminal 53 receives the IPv4 packet transmitted from the translator 55 (c3), the IPv4 terminal 53 performs address conversion of the IPv4 packet based on the updated address conversion information table 45.
[0045]
Specifically, the TCP / IPv4 reception processing unit 41 of the IPv4 terminal 53 receives the previous IPv4 packet flowing through the IPv4 network 54 and passes it to the address translation processing unit 43. When receiving the packet, the address translation processing unit 43 extracts the IPv4 address “192.168.10.3”, which is the source IP address of the packet, and addresses the IPv6 address associated with the extracted IPv4 address. Search from the conversion information table 45. Since the contents of the address conversion information table 45 are updated in (c2), the IPv6 address “:: 1234: 5678: 9abc” is extracted here. The address translation processing unit 43 sets the IPv6 address “:: 1234: 5678: 9abc” in the packet as the source IP address, and sends this packet to the IPv6 application. As the destination IP address, an IPv6 address obtained by extending the IPv4 address to the IPv4-mapped-IPv6 address shown in FIG. 12B is used. By performing such address translation, 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 more convenient that the received IP address is expressed by an IPv6 address.
[0046]
Further, the IPv6 application may send a packet to the IPv6 terminal 51 as a response process. In this case, the IPv6 application expands the IPv6 address of its own IPv4 address “133.144.95.22” as the source IP address into the IPv4-mapped-IPv6 address shown in FIG. “:: ffff: 133.144.95.22” is set, and the IPv6 address “:: 1234: 5678: 9abc” of the IPv6 terminal 51 is set as the destination IP address. This packet is transferred to the address translation processing unit 43, and the address translation opposite to the previous one is performed. That is, the address conversion processing unit 43 replaces the IPv6 address “:: 1234: 5678: 9abc” set as the destination IP address with the IPv4 address “192.168.10.3”. For the source IP address, the IPv4 address extracted from the lower 32 bits of the IPv6 address is used. Thereafter, the TCP / IPv4 transmission processing unit 42 sends the packet (IPv4 packet 57: FIG. 1) subjected to the conversion processing by the address conversion processing unit 43 to the translator 55 (c4).
[0047]
The IPv4 / v6 reception processing unit 31 of the translator 55 takes in the IPv4 packet 57 flowing through the IPv4 network 54 (b8) 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 address conversion information. Search from the table 35. Here, the IPv6 address “:: 1234: 5678: 9abc” is extracted (b9). After that, the header conversion unit 33 sets the IPv4-mapped-IPv6 address “:: ffff: 133.144.95.22” of the IPv4 terminal 53 as the transmission source IP address in the packet, and as the destination IP address , IPv6 address “:: 1234: 5678: 9abc” extracted earlier is set. In addition to such address conversion, the header conversion unit 33 simultaneously executes various processes for converting the IPv4 header into the IPv6 header (b10). The IPv4 / IPv6 transmission processing unit 32 sends the packet subjected to the conversion process of (b10) to the IPv6 terminal 51 (b11). Thereafter, the IPv6 terminal 51 receives this packet (a2).
[0048]
The IPv4 address associated with the IPv6 address may be released when a series of communications between the IPv6 terminal 51 and the IPv4 terminal 53 is completed. Further, an entry in the address translation information table may be deleted in accordance with a command issued at the time of network system management. Further, the time after communication is stopped may be stored in the option field of the address conversion information table, and the assigned IPv4 address that has timed out may be forcibly released at that time.
[0049]
Next, packet exchange when communication is started from the IPv4 terminal 53 side will be described with reference to the flowchart of FIG.
[0050]
In this case as well, the IPv6 address “:: 1234: 5678: 9abc” is assigned to the IPv6 terminal 51, and the IPv4 address “133.144.95.22” is assigned to the IPv4 terminal 53. I will do it.
[0051]
Then, the IPv6 application of the IPv4 terminal 53 sets its own IPv4 address “133.144.95.22” as the source IP address in the packet to be sent, and the IPv6 address “:: of the IPv6 terminal 51 as the destination IP address”. 1234: 5678: 9abc "is set. This packet is passed to the address translation processing unit 43. When receiving the packet, the address translation processing unit 43 extracts the IPv6 address that is the destination IP address included in the packet, and the IPv4 address associated in advance with the extracted IPv6 address is converted into the address translation information table 45. Search from among them (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 IPv6 address described above. Here, the IPv4 address “192.168.10.3” is assigned to the IPv6 address “:: 1234: 5678: 9abc” (c2). The address conversion processing unit 43 transmits these correspondences as address conversion information to the translator 55 (c3). The format of a packet for exchanging 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 translation information table 45 is shown in FIG. Note that a plurality of IPv4 addresses to be allocated are prepared in advance, and these are stored in a memory in the IPv4 terminal 53 (not shown). The address conversion information table 45 itself is also stored in this memory. Thereafter, 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 as it is. In addition to such address conversion, the address conversion processing unit 43 simultaneously executes various processes for converting the IPv6 header into the IPv4 header (c5). Thereafter, the TCP / IPv4 transmission processing unit 42 sends the packet (IPv4 packet 57: FIG. 1) subjected to the conversion processing by the address conversion processing unit 43 to the translator 55 (c6). In the search process of (c1), when the corresponding IPv4 address is found, this IPv4 address is adopted as the source IP address, and the processes of (c2), (c3), and (c4) are skipped. Is done.
[0052]
On the other hand, when the translator 55 receives the address translation information sent from the IPv4 terminal 53 (b1), the translator 55 updates the contents of the address translation information table 35 using the address translation information (b2). Thereby, the contents of the address translation information table 45 of the IPv4 terminal 53 match the contents of the address translation information table 35 of the translator 55. Specifically, the update of the content of the address translation information table 35 is performed by the address translation information exchange unit 34. The transmission of the address translation information in (c3) is performed not only for the translator 55 but also for all IPv4 terminals 53 that own the address translation information table 45, and the contents of each address translation information table 45 are updated. The In this way, the assigned IPv4 address does not overlap between each IPv4 terminal 53 and the translator.
[0053]
Then, the IPv4 / v6 reception processing unit 31 of the translator 55 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 address conversion information. Search from the table 35. Since the contents of the address conversion information table 35 are updated in (b2), the IPv6 address “:: 1234: 5678: 9abc” is extracted here (b4). After that, the header conversion unit 33 sets the IPv4-mapped-IPv6 address “:: ffff: 133.144.95.22” of the IPv4 terminal 53 as the transmission source IP address in the packet, and as the destination IP address , IPv6 address “:: 1234: 5678: 9abc” extracted earlier is set. In addition to such address conversion, the header conversion unit 33 simultaneously executes various processes for converting the IPv4 header into the IPv6 header (b5). The IPv4 / IPv6 transmission processing unit 32 sends the packet subjected to the conversion process of (b5) to the IPv6 terminal 51 (b6). Thereafter, the IPv6 terminal 51 receives this packet (a1).
[0054]
Further, the IPv6 terminal 51 may send an IPv6 packet 51 to the IPv4 terminal 53 as a response process. In this case, when sending the IPv6 packet 56 to the IPv6 network 52 (a2), the IPv6 terminal 51 sets its own IPv6 address “:: 1234: 5678: 9abc” as the source IP address in its header. The IPv4-mapped-IPv6 address “:: ffff: 133.144.95.22” of the IPv4 terminal 53 is set as the destination IP address. The IPv6 packet 56 is sent to the IPv4 terminal 53 via the translator 55 (c7). The processing of the translator 55 ((b7), (b8), (b9), b (10)) is the same as (b1), (b2), (b6), (b7) in FIG. Do not repeat the explanation.
[0055]
For the IPv4 address assigned to the IPv6 address, a release process similar to that described above may be performed.
[0056]
Next, the type B IPv4 terminal 53 will be described.
[0057]
As described above, the type B IPv4 terminal 53 is a terminal that has an IPv4 application and owns the above-described address translation information. In the type B IPv4 terminal 53, as shown in FIG. 3B, a TCP / IPv4 process 81, an address conversion process 82, an address conversion process 83, and an IPv4 application process 85 are performed. The IPv4 application process 85 is executed on the TCP / IPv4 process 81 via the IPv4 socket interface as shown in FIG. These hierarchical structures are the same as those of the conventional IPv4 terminal 53, and the IPv4 application process 85 receives the IP address of the packet raised from the TCP / IPv4 process 81 as the IPv4 address. The TCP / IPv4 processing 81 is handled by the TCP / IPv4 reception processing unit 41 and the TCP / IPv4 transmission processing unit 42. The address conversion processing unit 43 is in charge of the address conversion processing 82. The address translation information exchange processing 83 is handled by the address translation information exchange processing unit 44.
[0058]
Thus, in the type B IPv4 terminal 53, the application side does not particularly need an IPv6 address.
[0059]
However, the user may want to know the IPv6 address of the communication partner for confirmation or the like.
[0060]
Therefore, the type B IPv4 terminal 53 outputs the IPv6 address of the communication partner on a display screen or the like.
[0061]
That is, when receiving the packet output from the IPv4 application, the address translation processing unit 43 of the type B IPv4 terminal 53 extracts the IPv4 address that is the transmission source IP address of the packet and associates it with the extracted IPv4 address. The existing IPv6 address is searched from the address conversion information table 45 and output to the display screen or the like.
[0062]
Further, in the type B IPv4 terminal 53, the user can arbitrarily associate the IPv6 address and the IPv4 address automatically performed by the translator or the type A IPv4 terminal.
[0063]
That is, the address conversion processing unit 43 updates the address conversion information table 45 in accordance with the user operation content. For example, when the user performs an operation of assigning the IPv4 address “192.168.10.3” to the IPv6 address “:: 1234: 5678: 9abc”, the address conversion information table of FIG. For example, 45 is set as shown in FIG. When the address translation information table 45 is updated, the address translation information exchange unit 44 packetizes this updated part (see FIG. 8) and transmits it to the translator 55 and other IPv4 terminals 53 that own the address translation information table. To do. As a result, the contents of the address translation information table 45 of each IPv4 terminal 53 match the contents of the address translation information table 35 of the translator 55.
[0064]
Since the packet exchange performed between the IPv6 terminal 51 and the type B IPv4 terminal 53 is the same as the previous flow described with reference to FIGS. 5 and 6, the description thereof will be omitted. .
[0065]
Next, the type C IPv4 terminal 53 will be described.
[0066]
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. This type C terminal 53 includes terminals in which the IPv4 application is stored in ROM and cannot be changed in software as it is. In the type C IPv4 terminal 53, as shown in FIG. 3C, the IPv4 application process 85 is executed on the TCP / IPv4 process 81 via the IPv4 socket interface. The TCP / IPv4 processing 81 is handled by the TCP / IPv4 reception processing unit 41 and the TCP / IPv4 transmission processing unit 42.
[0067]
Note that type C IPv4 terminal 53 cannot start communication from the terminal side due to its configuration, but if communication is started from the other side, there is no particular problem as shown below.
[0068]
When 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 designates them in the data portion of the received packet. The predetermined processing is performed. Thereafter, if necessary, the IPv4 application packs the processing result into a packet and passes it to the TCP / IPv4 transmission processing unit 42. At this time, the IPv4 application replaces the extracted destination IP address and source IP address, and sets these in the packet. For example, the IPv4 address “133.144.95.22” is stored in the destination IP address “field” of the received packet, and the IPv4 address “192.168.10.3” is stored in the source IP address “field”. The IPv4 address “192.168.10.3” is stored in the destination IP address “field”, and the IPv4 address “133.144.95.22” is stored in the source IP address “field”. . This packet is sent to the IPv4 network 54 by the TCP / IPv4 transmission processing unit 42 and delivered to the translator 55.
[0069]
The 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. Configured as shown.
[0070]
This IPv6 / v4 translator has a CPU 71, a memory 72, and network interfaces 73-1, 73-2 to 73-n. The CPU 71 manages the memory 72 and controls the network interfaces 73-1, 73-2 to 73-n. Various programs are stored in the memory 72 in advance, and these programs are executed by the CPU 71 as necessary, so that the IPv4 / v6 reception processing unit 31 and the IPv4 / v6 transmission processing shown in FIG. The unit 32, the header conversion unit 33, the address conversion information exchange unit 34, and the address conversion information table 35 are realized.
[0071]
In FIG. 1, since there is one IPv6 network 52 and one IPv4 network 54, for example, 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. Will be. In this case, the network interface 73-1 captures the IPv6 packet flowing through the IPv6 network 52 and stores it in the memory 72, and the network interface 73-2 generates the IPv4 packet generated by performing header conversion or the like on the IPv4 network 54. Send it out. Even when a packet is sent in the reverse direction, each of the network interfaces 73-1 and 73-2 performs the reverse operation. Note that when there are a plurality of IPv6 and IPv4 networks, the network interface is used according to the number.
[0072]
Also, the actual hardware of the IPv4 terminal is configured as shown in FIG. 10B, for example.
[0073]
This 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. Various programs are stored in the memory 72 in advance. For example, in the case of a type A IPv4 terminal, a program in the memory 72 is executed by the CPU 71 as necessary, and a TCP / IPv4 reception processing unit 41, a TCP / IPv4 transmission processing unit 42, an address conversion processing unit 43, an address conversion information exchange. A processing unit 44, an address translation information table 45, and an IPv4 application are realized. The network interface 73 captures the IPv4 packet flowing through the IPv4 network 54 and stores it in the memory 72, and sends out the IPv4 packet generated by performing address conversion or the like to the IPv4 network 54.
[0074]
Further, for a specific IPv6 terminal, an IPv4 address may be assigned in advance and stored in the address translation information table. In this way, the processing time for allocation is reduced.
[0075]
Further, the present invention is not limited to the network configuration as shown in FIG. For example, the present invention can be applied to a network in which an IPv4 network and an IPv6 network are mixed. FIG. 9 shows an IPv4 / v6 mixed network 64 in which an IPv4 terminal 62 and an IPv6 terminal 61 are connected. In the IPv4 / v6 mixed network 64, the IPv4 packet 66 and the IPv6 packet 65 coexist, but the IPv4 / v6 translator 63 takes these into itself, and if necessary for the fetched packet, it will be explained earlier. The address conversion and header conversion performed are performed and returned to the network. By doing so, communication using the IPv4 packet 66 is performed between the IPv4 terminal 62 and the translator 63, and communication using the IPv6 packet 65 is performed between the translator 63 and the IPv6 terminal 61.
[0076]
In addition, the present invention is not limited to the connection between the IPv4 network and the IPv6 network, and two types of networks (the first type IP network and the second type) that have different IP address assignment systems due to differences in version or the like. It can be applied to a certain type of IP network.
[0077]
【The invention's effect】
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) A translator provided between the first type IP network and the second type IP network when starting communication with the target device B, which is one of the plurality of existing target devices, or The target device A assigns the first type IP address to the second type IP address assigned to the target device B, and in the first type IP network, the first type IP address is assigned. Communication.
[0078]
Therefore, in order to communicate with the target device A of the first type IP network, useless address setting in which the first type IP address is given in advance to the target device B existing in the second type IP network. The first type IP address which is scarce is effectively utilized.
[0079]
In addition, since the first type IP address assigned to the target device A is closed and used in the first type IP network, no problem occurs even if the same IP address is used in the external network. Further effective utilization of the seed IP address can be achieved.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an example of a network to which the present invention is applied.
FIG. 2 is a block diagram showing functions of an IPv4 / v6 translator used in the network of FIG. 1;
FIG. 3A is an explanatory diagram showing an outline of processing performed in a type A IPv4 terminal connected to the network of FIG. 1;
FIG. 3B is an explanatory diagram showing an outline of processing performed in a type B IPv4 terminal connected to the network of FIG.
FIG. 3C is an explanatory diagram showing an outline of processing performed in a type C IPv4 terminal connected to the network of FIG.
4 is a block diagram showing functions of a type A IPv4 terminal connected to the network of FIG. 1;
FIG. 5 is a flowchart showing a communication procedure (part 1) between an IPv6 terminal and an IPv4 terminal in the network of FIG. 1;
FIG. 6 is a flowchart showing a communication procedure (part 2) between the IPv6 terminal and the IPv4 terminal in the network of FIG. 1;
7 is an explanatory diagram showing an example of an address translation information table provided in each of the type A and B IPv4 terminals and the IPv4 / v6 translator connected to the network of FIG. 1;
8 is an explanatory diagram showing a format of a packet for transmitting storage information in 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. 11 (a) is an explanatory diagram of a format of an IPv6 header.
FIG. 11B is an explanatory diagram of the format of the IPv4 header.
FIG. 12A is an explanatory diagram of a format of an IPv4-compatible-IPv6 address.
FIG. 12B: Explanatory drawing 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: TCP / 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: IPv4 terminal, 54 : IPv4 network, 55, 63: IPv4 / v6 translator, 56, 65: IPv6 packet, 57, 66: IPv4 packet, 64: IPv6 / v4 mixed network, 71: CPU, 72: memory, 73: network interface, 81: TCP / IPv4 processing, 82: A 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

Claims (16)

In a terminal connected to a network and transmitting / receiving packets to / from the network,
A storage unit for storing an IPv6 application program;
A processing unit that executes an IPv6 application program stored in the storage unit and generates an IPv6 packet including an IPv6 header;
A holding unit for holding a plurality of IPv4 addresses;
An arbitrary one of the plurality of IPv4 addresses held in the holding unit is assigned to an IPv6 address stored as a destination address in the IPv6 header of the IPv6 packet, and the IPv6 header is used as the destination address. A conversion unit that stores an arbitrary IPv4 address and generates an IPv4 packet by converting the IPv6 header into an IPv4 header having a header format different from the IPv6 header;
Terminal; and a transmission unit that transmits the IPv4 packet to the network. 2. The terminal according to claim 1, further comprising: a second storage unit that stores the IPv6 address in association with the arbitrary IPv4 address assigned from the plurality of IPv4 addresses held in the holding unit. Furthermore, the terminal characterized by having. In a terminal connected to a network and transmitting / receiving packets to / from the network,
A first storage unit for storing an IPv6 application program;
A processing unit that executes an IPv6 application program stored in the storage unit and 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;
An IPv4 address associated with an IPv6 address stored as a destination address in the IPv6 header of the IPv6 packet and stored in the second storage unit is extracted from the second storage unit, and the IPv6 header is extracted from the second storage unit. A conversion unit that stores the IPv4 address as a destination address, converts the IPv4 header to a different IPv4 header format and generates an IPv4 packet;
Terminal; and a transmission unit that transmits the IPv4 packet to the network. 4. The terminal according to claim 3 , further comprising a third storage unit that holds a plurality of IPv4 addresses, wherein the conversion unit includes the plurality of IPv4 addresses held in the third storage unit. terminal, wherein the storing in the second storage unit any one in association with the IPv6 address. The terminal according to claim 1 or claim 3, wherein the conversion unit further converts the IPv4-mapped-IPv6 address of the terminal itself, which is stored as the source address in the IPv6 header into the second IPv4 address The terminal that converts the IPv6 header into an IPv4 header in which the second IPv4 address is stored as a source address. The terminal according to claim 2 or claim 3, further comprising a receiving unit for receiving an IPv4 packet from the network, when the receiving unit receives the IPv4 packet, the converting unit, the IPv4 packet the received IPv4 A second IPv6 address stored in association with the second IPv4 address stored in the header as the source address is extracted from the second storage unit, and the IPv4 header is used as the source address in the first A terminal characterized by converting to an IPv6 header in which an IPv6 address of 2 is stored. 7. The terminal according to claim 6 , wherein the conversion unit includes a third IPv4 address of the terminal stored as a destination address in the IPv4 header, and a third IPv4 address including the third IPv4 address in lower 32 bits. It converted to an IPv6 address, the IPv4 header, and converting the IPv6 header Examples destination address third IPv6 address is stored the terminal. 7. The terminal according to claim 6 , wherein the conversion unit includes an IPv4-mapped-IPv6 address including the third IPv4 address as a third IPv4 address of the terminal itself stored as a destination address in the IPv4 header. terminal converts, the IPv4 header, and converting the IPv6 header the IPv4-mapped-IPv6 address address as the destination address is stored in. In a packet transmission / reception method in a terminal connected to a network, a plurality of IPv4 addresses are held in advance, an IPv6 application program is executed, an IPv6 packet including an IPv6 header is generated, and stored as a destination address in the IPv6 header of the IPv6 packet An arbitrary one of the plurality of IPv4 addresses held is assigned to the held IPv6 address, the arbitrary IPv4 address is stored with the IPv6 header as a destination address, and the IPv6 header is a header format Is converted into a different IPv4 header, 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. Transmission / reception method. 10. The packet transmission / reception method according to claim 9 , wherein the IPv6 address and the arbitrary IPv4 address assigned from the plurality of IPv4 addresses held are stored in association with each other. Method. In a packet transmission / reception method in a terminal connected to a network, an IPv6 address and an IPv4 address are stored in association with each other, an IPv6 application program is executed, an IPv6 packet including an IPv6 header is generated, and the IPv6 header of the IPv6 packet is generated The IPv4 address stored in association with the IPv6 address stored as the destination address is extracted, the IPv6 header is used as the destination address, the IPv4 address is stored as the destination address, and the IPv4 header is different in header format from the IPv6 header Packet transmission / reception, generating an IPv4 packet from the data contained in the IPv6 packet and the IPv4 header, and transmitting the IPv4 packet to the network Law. 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 plurality of IPv4 addresses is stored in association with the IPv6 address. Transmission / reception method. 12. The packet transmission / reception method according to claim 9 or 11 , wherein a lower 32 bits are extracted from an IPv4-mapped-IPv6 address of the terminal itself stored as a source address in the IPv6 header to obtain a second IPv4 address. And a packet transmission / reception method characterized by converting the IPv6 header into an IPv4 header in which the second IPv4 address is stored as a source address. 12. The packet transmission / reception method according to claim 10 or 11 , wherein when an IPv4 packet is received from the network, the packet is associated with a second IPv4 address stored as a source address in an IPv4 header of the received IPv4 packet. 2. A packet transmission / reception method characterized by extracting a stored second IPv6 address and converting the IPv4 header into an IPv6 header storing the second IPv6 address as a source address. 15. The packet transmission / reception method according to claim 14 , wherein a third IPv4 address of the terminal itself stored as a destination address in the IPv4 header, and a third IPv6 address including the third IPv4 address in lower 32 bits. And a packet transmission / reception method, wherein the IPv4 header is converted into an IPv6 header in which the third IPv6 address is stored as a destination address. 15. The packet transmission / reception method according to claim 14 , wherein a third IPv4 address of the terminal itself stored as a destination address in the IPv4 header is converted to an IPv4-mapped-IPv6 address, and the IPv4 header is converted to a destination address. A packet transmission / reception method characterized in that the packet is converted into an IPv6 header in which the IPv4-mapped-IPv6 address is stored.

Images