CN1529480B - A method of IP network protocol conversion - Google Patents

Abstract

The invention relates to the technical field of computer network communication. A method for IPV6 message penetration through IPV4NATs is a network protocol conversion technology during the coexistence period of IPV4 and IPV6. The method mainly solves the following problems: for IPV6 behind one or more IPV4 NATs The /IPV4 dual-protocol host provides general IPV6 address configuration, supports IPV6 message communication between IPV6/IPV4 dual-protocol hosts, and between IPV6/IPV4 dual-protocol hosts and IPV6 hosts. In order to penetrate IPV4NATs, IPV6 packets are encapsulated in IPV4-UDP (IPV4-UDP, IPV4 User Datagram Protocol, IPV4 User Datagram Protocol) packets. Features of the method: 1: The assigned IPV6 address is a general IPV6 address, and it is not necessary to include the captured external IPV4 address of the host computer and external endpoint parameters in the IPV6 address, nor does it need to apply for a specific prefix from IANA. 2: Obtain the IPV4 address of the IPV6 access router through WEB. 3: Support IPV6 packets to penetrate various types of IPV4 NATs.

Description

A method of IP network protocol conversion

technical field

The invention relates to the technical field of computer network communication, in particular to a method for IPV6 messages to penetrate IPV4NATs. A kind of IPV6 (IPV6, Internet Protocol Version 6, the 6th edition Internet Protocol) message penetrates IPV4 NATs (IPV4NATs, Internet Protocol Version 4 Network Address Translators, the 4th edition Internet Protocol Network Address Translator) method is a kind of IPV4 and IPV6 Network protocol conversion technology in the period of coexistence. The method mainly solves the following problems: providing general IPV6 address configuration for IPV6/IPV4 dual-protocol hosts located behind one or more IPV4NATs, supporting communication between IPV6/IPV4 dual-protocol hosts, and between IPV6/IPV4 dual-protocol hosts and IPV6 hosts IPv6 message communication. In order to penetrate IPV4NATs, IPV6 packets are encapsulated in IPV4-UDP (IPV4-UDP, IPV4 User Datagram Protocol, IPV4 User Datagram Protocol) packets.

Background technique

During the coexistence period of IPV4 and IPV6, in order to solve the problem of IPV6 packet intercommunication between the IPV6 host in the IPV4 network and the IPV6 host in the IPV6 network, many solutions have been proposed, such as 6to4 protocol, ISATAP protocol (ISATAP, Intrasite automatic tunnelAddressing Protocol , Internal Set Automatic Tunnel Address Protocol) and so on. The common feature of these protocols is that the IPV6 packets are encapsulated into the IPV4 packets, and the IPV6 packets are transmitted through the IPV4 network. However, the above method cannot solve the problem of IPV6 packets penetrating IPV4 NATs. The problem is specifically described as: the IPV6/IPV4 dual-protocol host behind the IPV4 NATs transmits IPV6 packets with the IPV6 host through the IPV4 NATs and IPV4 network; or the IPV6/IPV4 dual-protocol host behind the IPV4 NATs, through IPV4 NATs and IPV4 networks, and IPV6/IPV4 dual-protocol hosts behind IPV4 NATs transmit IPV6 packets to each other.

According to the provisions of the IPV4 protocol: TCP packets are encapsulated in IPV4 packets, and the value of the protocol field of the IPV4 header needs to be set to 6; UDP packets are encapsulated in IPV4 packets, and the value of the protocol field of the IPV4 header needs to be set to 17; IPV6 The packet is encapsulated in an IPV4 packet, and the value of the protocol field in the IPV4 header needs to be set to 41. Typical IPV4 NATs only transmit IPV4 packets with an IPV4 header protocol field value of 6 or 17, and do not transmit IPV4 packets with a protocol field value of 41, so IPV6 packets encapsulated in IPV4 cannot penetrate typical IPV4 NATs.

In order to achieve IPV6 packets to penetrate IPV4 NATs, Microsoft Corporation of the United States proposed the Teredo protocol. The basic method of this protocol is to encapsulate IPV6 packets in IPV4 UDP packets, and implement IPV6 packets to penetrate IPV4 NATs through UDP packets. As of the application period of the present invention, the Teredo protocol is still being perfected, and the Teredo protocol submitted by Microsoft to the IETF (Internet Engineering Task Force, Internet Engineering Task Force) is in the draft stage; meanwhile, Microsoft has deployed the Teredo protocol on Windows XP .

As far as the application of the present invention, the Teredo protocol needs to assign the IPV6 address of a specific format to the dual-protocol host behind the IPV4 NATs—the Teredo address. The Teredo address contains a fixed prefix with a length of 32 bits. The legal use of the fixed prefix on the Internet must be approved by IANA (IANA, The Internet Assigned Numbers Authority, Internet Assigned Numbers Authority). The Teredo address also includes the external IPV4 address assigned by IPV4 NATs and the external UDP port information. The latter is a dynamically changing parameter, which will cause the Teredo address to be dynamic. This feature will bring adverse effects to mobile IPV6 applications, high-level applications based on DNS, and security mechanisms based on IPV6 address filtering. In addition, as of the application of the present invention, the Teredo protocol does not provide support for the IPV6 message communication of the dual-protocol host behind the IPV4 NATs of the symmetric NAT type.

The method proposed by the present invention distributes the general IPV6 address to the dual-protocol host behind the IPV4 NATs, does not need to include the external IPV4 address and external UDP port information distributed by the IPV4 NATs in the IPV6 address, fully supports mobile IPV6 applications, and is based on DNS High-level application, security mechanism based on IPV6 address filtering. Since it does not contain a specific prefix, there is no need to apply for a special prefix from the IANA agency. In addition, the present invention provides IPV6 connectivity support for dual-protocol hosts behind various types of IPV4 NATs—that is, IPV6 message communication between dual-protocol hosts and IPV6 hosts, and between dual-protocol hosts and dual-protocol hosts. Based on the principle of the present invention, the principle prototype of IPV6 message penetration IPV4 NATs related equipment has been realized.

Contents of the invention

The object of the present invention is to provide a kind of IPV6 message penetration IPV4 NATs method.

Technical scheme of the present invention:

Provide general IPV6 address configuration for IPV6/IPV4 dual-protocol hosts located behind one or more IPV4 NATs, support IPV6 message communication between IPV6/IPV4 dual-protocol hosts, and between IPV6/IPV4 dual-protocol hosts and IPV6 hosts. The specific steps of the method are as follows:

Step 1: IPV6 network access router parameter configuration based on WEB mode;

Step 2: Establish an IPV4 UDP tunnel between the dual-protocol host and NAR;

Step 3: IPV6 packet communication between hosts.

Step 1——IPV6 network access router parameter configuration based on WEB: The IPV6 network access router publishes device information, including the following: IPV4 address, device name, device location, and service fee, to NARP for user selection .

Wherein step 1——IPV6 network access router parameter configuration based on WEB mode: the user adopts WEB mode to configure the IPV4 address parameters of the NAR, and save the IPV4 address parameters of the NAR to the communication configuration file of the dual-protocol host.

Among them, step 2——establish an IPV4 UDP tunnel between the dual-protocol host and the NAR, before the dual-protocol host establishes an IPV4 UDP tunnel with the NAR, obtain the IPV4 address of the NAR from the dual-protocol host communication configuration file. Wherein step 2——establish IPV4 UDP tunnel between dual-protocol host and NAR, IPV6 network access router captures the external UDP port and IPV4 address parameter of dual-protocol host from the UDP message that dual-protocol host sends; Assign to dual-protocol then A common IPV6 address for the host; at the same time, an idle UDP port number is assigned to the dual-protocol host, which is used to establish an IPV4 UDP tunnel between the dual-protocol host and NAR; finally, the mapping relationship between the three parameters is saved in the IPV6 network In the IPV4 UDP tunnel mapping relationship file of the access router.

Among them, step 2——establish an IPV4 UDP tunnel between the dual-protocol host and NAR, and the IPV6 network access router assigns the dual-protocol host a general IPV6 address, which is a routable IPV6 network and belongs to the IPV6 network access The IPV6 address of the router's routing domain does not need to include the external IPV4 address and external UDP port information assigned by IPV4 NATs in the IPV6 address, nor does it need to contain a specific address prefix.

Wherein step 3—IPV6 message communication between hosts, after the IPV6 network access router receives the IPV6 message from the direction of the IPV6 network, according to the destination address in the message, map from the IPV4 UDP tunnel established in step 2 The corresponding UDP tunnel is searched in the relationship file, and if there is a corresponding mapping relationship, the IPV6 message is forwarded to the UDP tunnel indicated by the mapping.

Wherein step 3—IPV6 message communication between hosts, in step 2, what the IPV6 network access router assigns to the dual-protocol host is a general IPV6 address that is routable in the IPV6 network and belongs to the routing domain of the IPV6 network access router , when communicating with IPV6 packets between hosts, use this address as the source address or destination address in the IPV6 packet to construct an IPV6 packet, which conforms to the principle of IPV6 packet routing and addressing, and the packet can finally be addressed to reach the IPV6 host or IPV6 access router.

1 Overview

The invention relates to an IPV6 message penetration IPV4 NATs communication method. Provide support for IPV6 packet interoperability between dual-protocol hosts, and between dual-protocol hosts and IPV6 hosts. The dual-protocol hosts can be located in NAT domains or IPV4 networks.

Compared with the Teredo protocol, the present invention has the following characteristics: 1. The IPV6 address assigned is a general IPV6 address, and does not need to include the external IPV4 address and external port parameters that the IPV4 NATs are assigned to the dual-protocol host in the IPV6 address, nor does it need Apply to the IANA agency for a specific prefix. 2. Obtain the IPV4 service address of the IPV6 access router through WEB. 3. Support IPV6 packets to penetrate various types of IPV4 NATs.

2. Network topology description

The present invention mainly comprises three kinds of functional units, and function definition is as follows:

●IPV6 network access router: a router that completes the centralized management of IPV4 UDP tunnels and the functions of IPV6 network access services.

●Network access router navigator: WWW server, used to save IPV6 network access router equipment information.

●Host tunnel manager: IPV4 UDP tunnel maintenance software, installed on the dual-protocol host.

For the convenience of description, the IPV6 network access router is referred to as NAR (NetworkAccess Router), the network access router navigator is referred to as NARP (Network AccessRouter Pilot), and the host tunnel manager is referred to as HTM (Host Tunnel Manager). IPV4 network address translators are referred to as IPV4 NATs (IPv4 network address translators)

Description of drawings

Fig. 1 is a network topology of the present invention and an IPV4 UDP tunnel establishment process diagram;

Fig. 2 is an IPV6 message communication diagram between the dual-protocol host and the IPV6 host of the present invention;

Fig. 3 is the communication figure of IPV6 message between the dual-protocol hosts located in different NAT domains of the present invention;

Fig. 4 is located in the NAT domain of the present invention and is located in the IPV6 message communication figure between the IPV4 network dual-protocol host;

Fig. 5 is a parameter configuration diagram of the WEB-based IPV6 network access router of the present invention.

The network topology related to the method of the present invention is shown in Figure 1.

There are three types of networks in Figure 1:

●NAT domain, hosts located in this domain are assigned private IPV4 addresses by IPV4 NATs;

●IPV4 network, hosts located on this network have public IPV4 addresses;

●IPV6 network, hosts located in this network have IPv6 addresses.

Among them, IPV4 NATs is located at the junction of NAT domain and IPV4 network, with private IPV4 address and public IPV4 address; NAR is located at the junction of IPV4 network and IPV6 network, with public IPV4 address and IPV6 address. NARP has a public IPV4 address and is located in an IPV4 network. HTM is installed on a dual-protocol host, which is located in a NAT domain or an IPV4 network.

In order to realize that the IPV6 message penetrates the IPV4 NATs, the present invention includes the following three key steps: establishing an IPV4 UDP tunnel; IPV6 message communication between the dual-protocol host and the IPV6 host, and IPV6 network access router parameter configuration based on the WEB mode. The specific implementation is as follows:

3. Establish an IPV4 UDP tunnel between the dual-protocol host and NAR

The method for establishing an IPV4 UDP tunnel between the dual-protocol host and NAR is described in detail as follows, and the process is shown in Figure 1. The specific process is shown by the arrow indicated by the number in the figure.

(1) After the dual-protocol host in the NAT domain accesses the IPV4 network through IPV4 NATs (the dual-protocol host in the IPV4 network directly accesses the IPV4 network), HTM accesses NARP, obtains the IPV4 address of NAR, and saves it in the communication configuration file of HTM .

(2) According to the IPV4 address of the NAR stored in the communication configuration file of the HTM, the HTM sends a UDP tunnel resource request message to the UDP listening service port corresponding to the NAR.

(3) After NAR receives the request, it captures the parameters that IPV4 NATs assigns to the dual-protocol host from the UDP message sent by HTM: including the IPV4 address and UDP port number; and then assigns an IPV6 address to the dual-protocol host, the address It belongs to the routing domain of the IPV6 network access router and can be routed in the IPV6 network; at the same time, a free UDP port number is assigned to the dual-protocol host, which is used to establish an IPV4 UDP tunnel between the dual-protocol host and NAR; finally, the three The mapping relationship between parameters is stored in the IPV4 UDP tunnel mapping relationship file of the IPV6 network access router.

(4) NAR sends the corresponding IPV4 UDP tunnel mapping relationship parameters in NAR (3) to HTM, and HTM adds three parameters to the communication configuration file of HTM.

(5) Between HTM and NAR, test the IPV4 NATs type according to the IPV4 NATs type test algorithm in the appendix. NAR passes the test result to HTM, and HTM adds this parameter to the communication configuration file of HTM.

(6) UDP tunnel is dynamically maintained between HTM and NAR. HTM maintains the mapping in IPV4 NATs by periodically sending Hello packets, and the sending cycle is shorter than the mapping lifetime of IPV4 NATs.

4. IPV6 message communication between hosts

4.1, IPV6 message communication between dual-protocol host and IPV6 host

To perform IPv6 message communication between the dual-protocol host in the NAT domain and the IPV6 host in the IPV6 network, it is first necessary to establish an IPV4 UDP tunnel between the dual-protocol host and the NAR. The dual-protocol host sends an IPV6 packet to the IPV6 host on the IPV6 network. The IPV6 packet passes through the IPV4 UDP tunnel, penetrates the IPV4 NATs and the IPV4 network, and reaches the NAR. The NAR is forwarded to the IPV6 network and automatically routed to the corresponding IPV6 host; the IPV6 host sends The IPV6 message to the dual-protocol host is automatically routed to the NAR in the IPV6 network, and the NAR passes the IPv6 message through the UDP tunnel, penetrates the IPV4 network and IPV4 NATs, and transmits it to the dual-protocol host.

Specifically, there are two situations: the dual-protocol host sends an IPV6 message to the IPV6 host, and the IPV6 host sends an IPV6 message to a dual-protocol host. See attached drawing 2. The specific process is shown by the arrow indicated by the number in the figure.

4.1.1 Dual-protocol hosts send IPV6 packets to IPV6 hosts

(1) The HTM of the dual-protocol host encapsulates the IPV6 message to be sent in an IPV4 UDP message, where the source address of the IPV6 message is the IPV6 address assigned by the IPV6 network access router, and the destination address is the IPV6 host in the IPV6 network address.

(2) The IPV4 UDP packet encapsulated with the IPV6 packet is forwarded to the IPV4 network through the IPV4 NATs and reaches the NAR.

(3) After the NAR receives it, it takes out the IPV6 message from the IPV4 UDP message and forwards it directly to the IPV6 network.

(4) Since the IPV6 address of the message complies with the IPV6 message routing addressing principle, the message will eventually be transmitted to the destination IPV6 host through the IPV6 routing system.

4.1.2 IPV6 hosts send IPV6 packets to dual-protocol hosts

(5) In the IPV6 network, the IPV6 host sends an IPV6 message to the dual-protocol host. The source address in the IPV6 message is the IPV6 address of the IPV6 host, and the destination address is the IPV6 address of the dual-protocol host.

(6) The IPV6 message is transmitted to the NAR through the IPV6 routing system.

(7) After NAR receives the IPV6 message, it searches for the corresponding UDP tunnel from the IPV4 UDP tunnel mapping relationship file according to the destination address in the message. If there is a corresponding mapping relationship, the IPV6 message is encapsulated in the IPV4 UDP message In, forward the IPV4 network. Among them, the source port number used by the IPV4 UDP message is the parameter assigned by NAR to the dual-protocol host, and the source IPV4 address is the IPV4 address of NAR; the destination port number and destination IPV4 address are the parameters assigned by IPV4 NATs to the dual-protocol host.

(8) The IPV4 UDP packet containing the IPV6 packet arrives at the IPV4 NATs, and is forwarded to the dual-protocol host through the IPV4 NATs. The HTM of the dual-protocol host takes out the IPv6 message from the IPV4 UDP message.

The method and process for performing IPV6 message communication between the dual-protocol host on the IPV4 network and the IPV6 host on the IPV6 network are similar to the above.

4.2. IPV6 message communication between dual-protocol hosts located in different NAT domains

To communicate IPV6 packets between dual-protocol hosts located in different NAT domains, it is first necessary to establish respective IPV4 UDP tunnels between the dual-protocol hosts and NAR. Dual-protocol hosts pass through their respective IPV4 UDP tunnels, penetrate IPV4 NATs and IPV4 networks, and realize IPV6 message intercommunication between dual-protocol hosts through their respective NAR forwarding functions and IPV6 network routing addressing functions. The IPV4 NATs corresponding to the sender’s dual-protocol host are called source IPV4 NATs, and the NAR is called source NAR; the IPV4 NATs corresponding to the receiver’s dual-protocol host are called destination IPV4 NATs, and NAR is called destination NAR. See attached drawing 3. The specific process is shown by the arrow indicated by the number in the figure.

The specific process is as follows:

(1) The HTM of the dual-protocol host encapsulates the IPV6 message to be sent in an IPV4 UDP message, where the source address of the IPV6 message is the IPV6 address assigned by the IPV6 network access router, and the destination address is the IPV6 address of the destination dual-protocol host address.

(2) The IPV4 UDP packet encapsulated with the IPV6 packet is forwarded to the IPV4 network through the source IPV4 NATs and reaches the source NAR.

(3) After the source NAR receives it, it takes out the IPV6 message from the IPV4 UDP message and forwards it directly to the IPV6 network.

(4) Since the IPV6 address of the message complies with the routing addressing principle of the IPV6 message, the message will eventually be transmitted to the destination NAR through the IPV6 routing system.

(5) After receiving the IPV6 message, the destination NAR searches for the corresponding UDP tunnel from the IPV4 UDP tunnel mapping relationship file according to the destination address in the message. If there is a corresponding mapping relationship, the IPV6 message is encapsulated in the IPV4 UDP message In this article, the IPV4 network is forwarded. The source port number used by the IPV4UDP message is the parameter assigned by the destination NAR to the dual-protocol host, and the source IPV4 address is the IPV4 address of the destination NAR; the destination port number and destination IPV4 address are the parameters assigned by the destination IPV4 NATs to the dual-protocol host .

(6) The IPV4 UDP message containing the IPV6 message arrives at the destination IPV4 NATs, and is forwarded to the destination dual-protocol host through the destination IPV4 NATs. The HTM of the destination dual-protocol host takes out the IPv6 message from the IPV4 UDP message.

4.3. IPV6 message communication between the NAT domain and the dual-protocol host on the IPV4 network

To perform IPv6 message communication between the dual-protocol host in the NAT domain and the dual-protocol host in the IPV4 network, it is first necessary to establish respective IPV4 UDP tunnels between the dual-protocol host and the NAR. Dual-protocol hosts pass through their respective IPV4 UDP tunnels, penetrate IPV4NATs and IPV4 networks, and realize IPV6 packet intercommunication between dual-protocol hosts through their respective NAR forwarding functions and IPV6 network routing addressing functions. The NAR corresponding to the dual-protocol host of the sender is called the source NAR; the NAR corresponding to the dual-protocol host of the receiver is called the destination NAR.

Specifically, there are two situations: the dual-protocol host in the NAT domain sends an IPV6 message to the dual-protocol host in the IPV4 network; the dual-protocol host in the IPv6 network sends an IPV6 message to the dual-protocol host in the NAT domain. The processing method and process of the first case are introduced below, and the specific process is shown by the arrow represented by numbers in FIG. 4 . The second case is similar.

(1) The HTM of the dual-protocol host in the NAT domain encapsulates the IPV6 message to be sent in an IPV4UDP message, where the source address of the IPV6 message is the IPV6 address assigned by the IPV6 network access router, and the destination address is the destination dual-protocol The IPV6 address of the host.

(2) The IPV4 UDP packet encapsulated with the IPV6 packet is forwarded to the IPV4 network through the IPV4 NATs and reaches the source NAR.

(3) After the source NAR receives it, it takes out the IPV6 message from the IPV4 UDP message and forwards it directly to the IPV6 network.

(4) Since the IPV6 address of the message complies with the routing addressing principle of the IPV6 message, the message will eventually be transmitted to the destination NAR through the IPV6 routing system.

(5) After receiving the IPV6 message, the destination NAR searches for the corresponding UDP tunnel from the IPV4 UDP tunnel mapping relationship file according to the destination address in the message. If there is a corresponding mapping relationship, the IPV6 message is encapsulated in the IPV4 UDP message In this article, the IPV4 network is forwarded. The source port number used by the IPV4UDP message is the parameter used by the destination NAR for the dual-protocol host, the source IPV4 address is the IPV4 address of the destination NAR; the destination port number and the destination IPV4 address are parameters used by the destination dual-protocol host.

(6) The IPV4UDP message containing the IPV6 message arrives at the destination dual-protocol host. The HTM of the destination dual-protocol host takes out the IPv6 message from the IPV4 UDP message.

5. IPV6 network access router parameter configuration based on WEB

In the process of establishing the IPV4 UDP tunnel between the dual-protocol host and NAR, the dual-protocol host needs to know the IPV4 service address of the IPV6 network access router on the IPV4 network side. Users can manually configure this parameter on the dual-protocol host, but it is inconvenient.

The method proposes adopting a WEB mechanism to help users select an IPV6 network access router and automatically configure required parameters.

The WEB configuration process is divided into the following two steps, and the specific process is shown by the arrow indicated by the number in Figure 5 .

(1) NAR device registration process: NAR publishes the device information, including the following content: IPV4 address, device name, device location, service fee, to the NARP---WWW server.

(2) User query process: the user accesses NARP through WEB, selects the most suitable NAR according to the device information list on the WEB page, and after clicking OK, the IPV4 address of the NAR is automatically added to the dual-protocol host communication configuration file.

Appendix - IPV4 NATs Type Test Algorithm

According to the security policy of IPV4 NATs for processing external IPV4 packets, it can be divided into restricted-NAT and cone-NAT; according to the resource allocation strategy of IPV4 NATs for internal IPV4 packets, it can be divided into symmetric NAT and asymmetric NAT; there are four types for this purpose IPV4 NATs types: cone-asymmetric-nat, restricted-asymmetric-nat, cone-symmetric-nat, restricted-symmetric-nat.

The IPV4 NATs type can be judged by the following basic algorithm:

(1) HTM sends a cone-NAT test request message to NAR, and the message is encapsulated in a UDP message. The destination address and UDP port number of the UDP message are the UDP tunnel dedicated resources allocated by NAR to HTM.

(2) NAR takes out the source address and source port address of the UDP packet, takes out the destination address and destination port address of the UDP packet; takes out the source address and source port address of the UDP packet, and another IPV4 address of NAR that is different from the destination address As the content of the cone-NAT test response message of NAR; the response message is encapsulated in a UDP message, and another IPV4 address is used as the source IPV4 address of the UDP message of the response message, and sent to the HTM; if the HTM receives it, it is determined that the HTM is in the cone -NAT domain, otherwise skip to step (5).

(3) If the HTM does not receive the cone-NAT test response message, the HTM sends a restricted-NAT test request message to the NAR, the message is encapsulated in a UDP message, and the destination address and UDP port number of the UDP message are assigned to the HTM by the NAR Dedicated resources for UDP tunnels.

(4) NAR takes out the source address and the source port address of the UDP packet, takes out the destination address and the destination port address of the UDP packet, and the source address and the source port address of the UDP packet of the UDP packet obtained in step (2), as NAR The restricted-NAT test response message content; the response message is encapsulated in a UDP packet, and the destination UDP port number and IPV4 address are taken out as the source UDP port number and IPV4 address of the UDP packet of the response message, and sent to the HTM; if the HTM receives If it is found, confirm that the HTM is in the restricted-NAT domain.

(5) The HTM sends a symmetric NAT test request message to the NAR, the message is encapsulated in a UDP packet, and the destination address of the UDP packet is another IPV4 address of the NAR.

(6) NAR takes out the source address and source port address of the UDP packet, takes out the destination address and the destination port address of the UDP packet, and uses them as the content of the symmetric NAT test response message; the response message is encapsulated in a UDP message to take out the destination UDP port number and The IPV4 address is sent to the HTM as the source UDP port number and IPV4 address of the UDP packet of the response message.

(7) According to the symmetric NAT test response message, the previously received cone-NAT test response message or the restricted-NAT test response message, HTM judges that the source port and IPV4 address are the same, and the destination port and IPV4 address are different. IPV4 NATs allocation Whether the external port and external IPV4 address of the IP address are the same. If they are different, it is determined that the HTM is in the symmetric-NAT domain; otherwise, it is in the asymmetric-NAT domain.

Claims (6)

1. A method for IP network protocol conversion, the method comprising the following functional units: the IPV6 network access router is to complete the IPV4UDP tunnel centralized management and the IPV6 network access service function router; the IPV6 network access router navigator is used to preserve the IPV6 The WWW server of network access router device information; The host tunnel manager is the IPV4UDP tunnel maintenance software installed on the dual-protocol host; it is characterized in that it is an IPV6/IPV4 dual-protocol host behind one or more IPV4 network address translators Provide general IPV6 address configuration, support IPV6 message communication between IPV6/IPV4 dual-protocol hosts, between IPV6/IPV4 dual-protocol hosts and IPV6 hosts, the specific steps of this method are as follows: Step 1: IPV6 network access router parameter configuration based on WEB mode; Step 2: set up the IPV4UDP tunnel between dual-protocol host and IPV6 network access router; Access the router navigator, after obtaining the IPV4 address of the IPV6 network access router, send a UDP tunnel resource request message to the corresponding UDP monitoring service port of the IPV6 network access router; (2) after the IPV6 network access router receives the request, Capture the parameters used by the IPV4 network address translator for the dual-protocol host from the UDP message sent by the host tunnel manager: including the IPV4 address and UDP port number; then assign an IPV6 address to the dual-protocol host, which belongs to the IPV6 network interface It can be routed in the IPV6 network; at the same time, a free UDP port number is assigned to the dual-protocol host, which is used to establish an IPV4UDP tunnel between the dual-protocol host and the IPV6 network access router; finally, the three parameters The mapping relationship between is stored in the IPV4UDP tunnel mapping relationship file of the IPV6 network access router; (3) the IPV6 network access router sends the obtained corresponding IPV4UDP tunnel mapping relationship parameter to the host tunnel manager, and the host tunnel manager will Three parameters are added to the communication configuration file of the host tunnel manager; (4) the IPV4 network address translator type is tested between the host tunnel manager and the IPV6 network access router, and the IPV6 network access router passes the test result to The host tunnel manager, the host tunnel manager adds the test result of the IPV4 network address translator type to the communication configuration file of the host tunnel manager; (5) dynamically maintains the UDP tunnel between the host tunnel manager and the IPV6 network access router, The host tunnel manager maintains the mapping in the IPV4 network address translator by regularly sending Hello packets, and the sending period is shorter than the mapping lifetime of the IPV4 network address translator; Step 3: IPV6 message communication between hosts. 2. according to the method for IP network protocol conversion described in claim 1, it is characterized in that, wherein step 1——IPV6 network access router parameter configuration based on WEB mode: IPV6 network access router will equipment information, comprise following content: IPV4 The address, device name, region where the device is located, and service charges are posted to the navigator of the IPV6 network access router for users to choose. 3. according to the method for IP network protocol conversion described in claim 1, it is characterized in that, wherein step 1---the IPV6 network access router parameter configuration based on WEB mode: the user adopts the IPV4 address parameter of WEB mode configuration IPV6 network access router , and save the IPV4 address parameter of the IPV6 network access router to the communication configuration file of the host tunnel manager. 4. according to the method for the described IP network protocol conversion of claim 1, it is characterized in that, wherein step 2---set up IPV4UDP tunnel between dual-protocol host and IPV6 network access router, dual-protocol host establishes IPV4UDP with IPV6 network access router Before tunneling, obtain the IPV4 address of the IPV6 network access router from the communication configuration file of the host tunnel manager. 5. according to the method for the described IP network protocol conversion of claim 1, it is characterized in that, wherein step 3---the IPV6 message communication between the host, after the IPV6 network access router receives the IPV6 message that comes from the IPV6 network direction , according to the destination address in the message, search for the corresponding UDP tunnel from the IPV4UDP tunnel mapping relationship file established in step 2, if there is a corresponding mapping relationship, then forward the IPV6 message to the UDP tunnel indicated by the mapping. 6. according to the method for the described IP network protocol conversion of claim 1, it is characterized in that, wherein step 3---the IPV6 message communication between the host computer, what IPV6 network access router distributes to the dual-protocol host computer in the step 2 is one in A general IPV6 address that is routable in the IPV6 network and belongs to the routing domain of the IPV6 network access router. When communicating with IPV6 packets between hosts, use this address as the source address or destination address in the IPV6 packet to construct an IPV6 packet, which conforms to Based on the principle of IPV6 packet routing and addressing, the packet can finally be addressed to an IPV6 host or an IPV6 access router.

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