CN100525295C - A method for implementing communication between IPv4 network and IPv6 network - Google Patents

Abstract

The invention relates to realization method for communication between IPv4 net and IPv6 net. When node of IPv4 communicate to node of IPv6, converses the objective address according to IPv4 address and corresponding port number, and realizes communication between node of IPv4 aforementioned and node of IPv6. Thereby, the invention is that when node of IPv4 communicate to node of IPv6, corresponding multiple objective IPv6 address can be mapped to a IPv4 address simultaneously based on corresponding port number, realizes the good use of IPv4 address during the address mapping process, solves the short problem of IPv4 address, saves efficiently the utilization of IPv4 address; besides, the invention has the advantage of realization process simple.

Description

A method for realizing communication between IPv4 network and IPv6 network

technical field

The invention relates to the technical field of network communication, in particular to a method for realizing communication between an IPv4 network and an IPv6 network.

Background technique

The current data network is dominated by IPv4 (Internet Protocol Version 4) technology. With the expansion of network scale, IPv6 (Internet Protocol Version 6) technology will gradually replace the current IPv4 technology with its advantages such as huge address space. However, such a thorough replacement requires a long-term process. In this long-term evolution process from IPv4 to IPv6, in order to share network resources, it is necessary to solve the problem of intercommunication between IPv4 network and IPv6 network, that is, to ensure that IPv6 nodes and IPv4 nodes can communicate with each other. Based on this need, NAT-PT (Network Address Translation-Protocol Translation, Network Address Translation Protocol) technology is produced, which provides a solution for the intercommunication between IPv4 network and IPv6 network. definition.

The main principle of NAT-PT technology is to set up a gateway device between the IPv6 network and the IPv4 network, which is called a NAT-PT gateway. Convert to and from IPv4 packets to adapt to the IP protocol type of the peer. Including protocol conversion (such as the conversion of IPv4 message header and IPv6 message header) and IP address conversion.

For the conversion from IPv6 message to IPv4 message, the conversion of IP address is to replace the IPv6 address with an identifiable IPv4 address. The specific method is that the NAT-PT gateway allocates a temporary IPv4 address from the IPv4 address pool to map the required Converted IPv6 address. For the conversion from IPv4 message to IPv6 message, it is necessary to replace the IPv4 address with the corresponding IPv6 address. The specific method is to allocate a special IPv6 address prefix, called NAT-PT prefix, and use the prefix + IPv4 address to form a new The IPv6 address is mapped to the IPv4 address that needs to be converted.

In order to have a further understanding of NAT-PT technology, an example is used to describe the IP address translation process in NAT-PT. As shown in Figure 1, the intermediate NAT-PT gateway includes an IPv4 address pool, assuming that the included IPv4 addresses are 101.1.1.1 to 101.1.1.10, which are used to map the IPv6 addresses that need to be converted, and assign NAT-PT prefixes, assuming that the prefixes are 3333::0/96, used to map the IPv4 address that needs to be converted; see Figure 1, assuming that in the IPv6 network on the left, the IPv6 addresses of node B and node A are 2001::1 and 2001::2 respectively; the IPv4 network on the right , the IPv4 address of node C is 132.1.1.1.

When an IPv6 node initiates a visit to an IPv4 node, take IPv6 node B (IPv6-B) preparing to communicate with IPv4 node C (IPv4-C) as an example, the specific process is: when it is necessary to send a message to node C, first The NAT-PT gateway needs to map the IPv4 address of node C as the destination address to an IPv6 address, and the method adopted is to use the NAT-PT prefix + IPv4 address, that is, 3333::132.1.1.1. In this way, when node B sends an IPv6 message, the corresponding source address is 2001::1, and the destination address is 3333::132.1.1.1. When the message passes through the NAT-PT gateway, the IPv6 address as the destination address is converted to IPv4 address, i.e. the actual address 132.1.1.1 of node C; NAT-PT gateway also needs to distribute an address (being 101.1.1.1 for example) from IPv4 address pool to map IPv6 source address, and IPv6 message is converted into IPv4 message, Send to IPv4 node C, thus completing the process of sending a message from node B to node C once.

When an IPv4 node initiates access to an IPv6 node, take IPv4 node C preparing to communicate with IPv6 node B as an example, the specific process is as follows: first, the NAT-PT gateway needs to map the IPv6 address of node B to an IPv4 address, assuming that the node The address 2001::1 of B is mapped to the corresponding IPv4 address 101.1.1.2; when node C sends an IPv4 packet to node B, the mapped IPv4 address 101.1.1.2 of node B can be directly used as the destination address. When the message passes through the NAT-PT gateway, the source address of the IPv4 message will also be mapped to the corresponding IPv6 address. The specific way is to add the NAT-PT prefix before the original IPv4 address, which is 3333::132.1.1.1; The destination address of the IPv4 message will also be mapped to the corresponding IPv6 address, that is, the actual address of node B 2001::1; the NAT-PT gateway converts the message into an IPv6 message and sends it to the IPv6 node B.

In order to ensure that the destination address of the IPv4 message can be mapped to the corresponding IPv6 address, the NAT-PT protocol also specifies the implementation method of DNS-ALG (Domain Name System Address Translation Application Gateway), which can be used to assist IPv4-initiated migration to IPv6 The address translation process of the accessed packets. As shown in Figure 2, the NAT-PT gateway needs to support DNS-ALG, that is, if the passing message contains a DNS (Domain Name System) message, in addition to converting the IPv6 and IPv4 protocol message headers, the DNS message must also be The text is converted; the DNS in the IPv6 network is an IPv6DNS server, which is responsible for responding to IPv6 DNS requests; the DNS in the IPv4 network is an IPv4DNS server, which is responsible for responding to IPv4 DNS requests.

Suppose IPv4 node C visits IPv6 node B. First, node C sends an IPv4 DNS request to obtain the IPv4 address of destination node B. When the request passes through the NAT-PT gateway, it is changed to an IPv6 DNS request, and the modified IPv6 address The DNS request is sent to the IPv6DNS server, and the IPv6DNS response is obtained, which contains the IPv6 address of node B. When the response message passes through the NAT-PT gateway, it is converted into an IPv4DNS response message, and the NAT-PT gateway allocates an IPv4 address from the IPv4 address pool The IPv6 address in the response message is replaced by the IPv4 address of Node B. After node C receives the DNS response message, it can use the IPv4 address as the destination address to access node B. The address translation process of the message is shown in FIG. 3 .

It can be seen from the previous description that during the NAT-PT conversion process, the IPv6 address is mapped using the IPv4 address pool. Whenever a new IPv6 address needs to be mapped, an IPv4 address is allocated from the address pool for use. Due to the relatively scarce IPv4 address resources at present, it is usually impossible to allocate a sufficiently large address pool, which causes the addresses in the address pool to be easily exhausted. Once there is no free address available for allocation in the address pool, all new connections established between IPv6 and IPv4 will not be normally processed by the NAT-PT gateway.

For this reason, for packets sent from an IPv6 network to an IPv4 network, the NAT-PT protocol also stipulates a conversion method based on port numbers, that is, in addition to converting the source address of the packet, the port number of the transport layer of the packet must also be translated to convert. Suppose there are two IPv6 packets that need to map their respective IPv6 source addresses to IPv4 addresses, but there is only one IPv4 address that can be mapped on the NAT-PT gateway. At this time, the port number conversion method can be used, as shown in Figure 4. In addition to address mapping, the source port of the IPv6 message is also mapped to a different IPv4 port. In this way, after the two messages are converted, although the IPv4 source address is the same, because the assigned IPv4 source port numbers are different, they still Two packets can be distinguished, and this processing method is called PAT (Port Number-Based Address Translation) method.

When an IPv6 packet needs to communicate with an IPv4 packet, since the destination address of the packet is in the form of NAT-PT prefix + IPv4 address, it can be directly mapped to an IPv4 address, while the destination port remains unchanged. For the source address and source port, the mapping is performed by dynamically assigning the source IPv4 address and assigning the port number; and since the value range of the port number is 0-65535, in principle, each IPv4 address can be multiplexed at the same time by this method To 65535 mappings, greatly improving the efficiency of IPv4 address usage.

However, the above method is limited to use when mapping IPv6 source addresses during the process of converting IPv6-initiated packets to IPv4, that is, it is only suitable for converting an IPv6 address as a source address into an IPv4 address. However, for the packet conversion initiated by the node of the IPv4 network to access the IPv6 network, it is still necessary to map the IPv6 address as the destination address to the corresponding IPv4 address, regardless of the port number. And, for the implementation method of DNS-ALG that the current NAT-PT agreement stipulates, also just use the IPv4 address allocated from the IPv4 address pool to map the destination IPv6 address, and then carry it to the source node in the IPv4 network by the DNS message, and The DNS message cannot carry the corresponding port number information. Because of this, the NAT-PT gateway cannot use the port number allocation method. In this way, the addresses of the IPv4 address pool are quickly exhausted by the DNS-ALG, that is, during the address translation process initiated by the IPv4 node to the IPv6 node, for any destination address that is an IPv6 address, the maximum Improvement of efficiency IPv4 address usage efficiency, that is, the maximum utilization of IPv4 addresses cannot be realized.

Therefore, although the intercommunication between IPv4 network nodes and IPv6 network nodes can be realized at present, the address mapping for IPv6 depends on the allocated IPv4 address pool, but IPv4 address resources are currently very tight, especially in China and other Asian countries.

Contents of the invention

The purpose of the present invention is to provide a method for realizing communication between an IPv4 network and an IPv6 network, thereby ensuring that when an IPv4 network accesses an IPv6 network, one IPv4 address can be applied to the mapping of multiple destination IPv6 addresses, effectively solving the shortage of IPv4 addresses The problem.

The purpose of the present invention is achieved through the following technical solutions:

The invention provides a method for realizing communication between an IPv4 network and an IPv6 network, comprising:

A. When a node in the IPv4 network initiates communication to a node in the IPv6 network, assign a corresponding IPv4 address and a corresponding port number to the destination address of this communication;

B, establish the corresponding relationship between the IPv6 address of the node in the IPv6 network as the destination end and the corresponding port number and the described IPv4 address and the corresponding port number;

C. Realize the communication between the nodes in the IPv4 network and the nodes in the IPv6 network according to the established correspondence.

Described step A comprises:

When a node in the IPv4 network initiates communication to a node in the IPv6 network, a corresponding IPv4 address and a corresponding port number are allocated for this communication in the IPv4 address pool on the NAT-PT (Network Address Translation Protocol) gateway;

And the step B includes:

The corresponding relationship between the IPv6 address and the corresponding port number of the node in the IPv6 network as the destination end and the allocated IPv4 address and the corresponding port number is established and saved in the NAT-PT gateway.

Described step C comprises:

The destination address and the destination port number of the message that the node in the IPv4 network sends to the node in the IPv6 network use the IPv4 address that step A distributes and the corresponding port number, and send;

C2, when described message passes through NAT-PT gateway, according to the corresponding relationship that step B establishes, the destination address and destination port number of message are converted into the actual IPv6 address and corresponding port of the node in the IPv6 network as destination end number and send it.

Described step C also includes:

When the node in the IPv6 network as the destination end returns a response message to the node in the IPv4 network as the source end, the NAT-PT gateway will return the source address of the response message and the corresponding port number to replace the step A distribution The IPv4 address and the corresponding port number are sent to the nodes in the IPv4 network.

The realization method of described IPv4 network and IPv6 network communication further comprises:

On the NAT-PT gateway, the IPv6 address and the corresponding port number of the node in the IPv6 network as the destination end are statically configured, and the corresponding relationship between the corresponding IPv4 address and the corresponding port number;

When a node in the IPv4 network initiates communication to a node in the IPv6 network, the communication between the node in the IPv4 network and the node in the IPv6 network is realized according to the established corresponding relationship.

As can be seen from the technical solution provided by the present invention above, in the present invention, when an IPv4 network node initiates a visit to an IPv6 network node, corresponding multiple different IPv6 addresses as destination addresses can be simultaneously mapped to a corresponding port number information based on the corresponding port number information. On the IPv4 address, it realizes the maximum utilization of IPv4 address resources during the address mapping process, solves the shortage of IPv4 addresses, and effectively saves the use of IPv4 addresses.

Moreover, the present invention adopts the method of implementing the destination address translation process of the message from the IPv4 network to the IPv6 network based on the port number, and also has the advantage of relatively simple implementation of the address translation process.

Description of drawings

Fig. 1 is the networking schematic diagram of IPv4 network and IPv6 network intercommunication;

Figure 2 is a schematic diagram of a DNS-based networking between an IPv4 network and an IPv6 network;

Fig. 3 is the address translation schematic diagram of IPv4 network sending message to IPv6 network in the prior art;

Fig. 4 is the address translation schematic diagram of IPv6 network sending message to IPv4 network in the prior art;

Fig. 5 is the address translation schematic diagram that IPv4 network sends message to IPv6 network among the present invention;

Fig. 6 is a flow chart of the method of the present invention.

Detailed ways

The present invention is mainly a supplement to the NAT-PT technology, so that in the process of accessing to the IPv6 network initiated by the IPv4 network, the corresponding address conversion process can effectively use limited IPv4 address resources and solve the problem of shortage of IPv4 addresses. The core idea realized by the present invention is: when a node in the IPv4 network initiates communication to a node in the IPv6 network, corresponding address conversion processing is performed according to the IPv4 address and the corresponding port number, and communication services are carried out between the nodes. As shown in Figure 5, that is to say that the essence of the present invention is to carry out mapping conversion between the IPv6 address and the port of any node in the IPv6 network as the destination end and the corresponding IPv4 address and the corresponding port, thereby realizing that the IPv4 network initiates the IPv6 network The address translation processing of the communications, fully utilizes the limited IPv4 address resources.

The present invention is an improvement to the address translation process in the process of interworking between the IPv4 network and the IPv6 network. Specifically, the present invention is only aimed at the address translation process in the communication process initiated by the node in the IPv4 network and the node in the IPv6 network proposed technical solutions.

The specific implementation of the present invention is shown in Fig. 5 and Fig. 6, comprises the following steps:

Step 61: statically configure the mapping relationship between IPv4 address and port number and IPv6 address and port number on the NAT-PT gateway;

That is, on the NAT-PT gateway, allocate free IPv4 addresses and free IPv4 ports from the IPv4 address pool, and establish a static address mapping relationship with the IPv6 addresses and service port numbers of corresponding nodes in the IPv6 network;

Of course, when a node in the IPv4 network initiates communication with a node in the IPv6 network, the NAT-PT gateway allocates an IPv4 address and a corresponding port number from the IPv4 address pool, and establishes a connection with the IPv6 node as the destination. Correspondence between IPv6 addresses and port numbers.

Step 62: When a node in the IPv4 network initiates communication with a node in the IPv6 network, the required destination IPv4 address is determined directly according to the address mapping relationship configured in step 61;

That is to say, when a node in the IPv4 network initiates communication with a node in the IPv6 network, the destination address and destination port number of the sent message are those of the destination node in the IPv6 network statically configured on the NAT-PT gateway. The IPv4 address and IPv4 port number corresponding to the IPv6 address and service port number.

Step 63: After receiving the message, the NAT-PT gateway converts the destination IPv4 address and port number into a corresponding IPv6 address and port number according to the statically configured mapping relationship;

That is, when the IPv4 message initiated by IPv4 passes through the NAT-PT gateway, it is necessary to perform address translation processing on the message, that is, according to the IPv6 address configured in step 61 and the corresponding port number and the IPv4 address and the corresponding port number Corresponding relationship, replace the destination address + port number of the packet with the actual IPv6 address of the destination end and the corresponding port number.

Step 64: Send the packet processed by the address translation to the IPv6 node as the destination.

The present invention also includes: when the IPv6 message responded by the IPv6 node passes through the NAT-PT gateway, the address conversion processing of the message is still required, that is, the IPv6 source address + source port in the message is replaced with the saved IPv4 address corresponding to the message. source address+source port, and send the message to the node in the IPv4 network (that is, the IPv4 node that initiates the communication).

Step 61 to step 64 have carried out corresponding description to the specific processing procedure of the present invention, and then in conjunction with specific application examples, the present invention is further described:

Still taking the node in the IPv4 network to initiate access to the node in the IPv6 network as an example, see Figure 1, assuming that IPv4 node C needs to access port 23 of IPv6 node A, then on the NAT-PT gateway, allocate from the IPv4 address pool The free address 101.1.1.3 and the free port 10001 map the IPv6 address and port of node A, and the corresponding relationship is: 101.1.1.3+10001<--->2001::2+23.

At this time, the destination address and port of the IPv4 packet sent by node C to node A use 101.1.1.3+10001. When the IPv4 message initiated by node C is converted by the NAT-PT gateway, the destination address and destination port of the message are changed from 101.1.1.3+10001 to 2001::2+23, and sent to node A.

When the IPv6 message responded by node A passes through the NAT-PT gateway for message conversion, the source address and source port of the message are changed from 2001::2+23 to 101.1.1.3+10001, and then sent to node C.

So far, the communication between node C and node A has been realized.

In the present invention, whenever a node in the IPv4 network initiates communication to a node in the IPv6 network, it is necessary to establish a corresponding address+port number correspondence at the NAT-PT gateway, for example, when node C wants to access node B at the same time When serving port 80, the NAT-PT gateway can assign the same IPv4 address and different ports to map the port 80 service of node B. The corresponding relationship is: 101.1.1.3+10002<---)2001::1+ 80.

It can be seen that, by the technical scheme provided by the present invention, many different communications from the IPv4 network to the IPv6 network can use the same IPv4 address in combination with different ports to map the destination IPv6 address and corresponding ports, thereby greatly The use of IPv4 addresses is saved.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (7)

1, the implementation method of a kind of IPv4 network and IPv6 network service is characterized in that, this method comprises:

A, when the node of the node in the IPv4 network in the IPv6 network initiated communication, for the destination address of this communication distributes the IPv4 address of a correspondence and corresponding ports number;

B, set up corresponding relation as the IPv6 address of the node in the IPv6 network of destination and corresponding ports number and described IPv4 address and corresponding ports number;

C, realize internodal communication in node and the IPv6 network in the described IPv4 network according to the corresponding relation of setting up.

2, the implementation method of IPv4 network according to claim 1 and IPv6 network service is characterized in that described steps A comprises:

When the node of the node in the IPv4 network in the IPv6 network initiated communication, in the IPv4 address pool on NAT-PT (network address translation protocol) gateway the IPv4 address of a correspondence of this allocation of communications and corresponding ports number;

And described step B comprises:

Set up and preserve corresponding relation at the NAT-PT gateway as the IPv4 address of the IPv6 address of the node in the IPv6 network of destination and corresponding ports number and distribution and corresponding ports number.

3, the implementation method of IPv4 network according to claim 2 and IPv6 network service is characterized in that described step C comprises:

The destination address of the message that the node of the node in C1, the IPv4 network in the IPv6 network sends and destination slogan use IPv4 address that steps A distributes and corresponding ports number, and send;

C2, when described message during through the NAT-PT gateway, the corresponding relation of setting up according to step B is converted to the destination address of message and destination slogan as the practical IP v6 address of the node in the IPv6 network of destination and corresponding ports number, and sends.

4, the implementation method of IPv4 network according to claim 3 and Pv6 network service is characterized in that described step C also comprises:

When described as the node in the IPv6 network of destination when returning response message as the node in the IPv4 network of source end, in IPv4 address that the NAT-PT gateway distributes the source address and the corresponding ports replacement step A of the response message that returns and corresponding ports number, and send to node in the described IPv4 network.

5, the implementation method of IPv4 network according to claim 1 and IPv6 network service is characterized in that this method further comprises:

Static configuration is as the corresponding relation of the IPv6 address of the node in the IPv6 network of destination and corresponding ports number and corresponding IPv4 address and corresponding ports number on the NAT-PT gateway;

When the node of the node in the IPv4 network in the IPv6 network initiated communication, realize internodal communication in node and the IPv6 network in the described IPv4 network according to the corresponding relation of setting up.

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