WO2009052668A1

WO2009052668A1 - A nat-pt device and a load-sharing method for nat-pt device

Info

Publication number: WO2009052668A1
Application number: PCT/CN2007/003648
Authority: WO
Inventors: Jun Yao; Shubo Guo; Hongxiang Liu
Original assignee: Zte Corporation
Priority date: 2007-10-22
Filing date: 2007-12-18
Publication date: 2009-04-30
Also published as: CN101150502A

Abstract

A NAT-PT device and a load-sharing method are disclosed. the said method includes the following steps: each of the NAT-PT processing single-boards is configured with different IPv6 prefix and IPv4 address pool resource; a source terminal initializes a flow of domain name resolution; a request message is sent to different single-boards to process with poll mode, and is sent to destination terminal; the responsive message is sent to the single-board, which processes said request message, to process and is sent to source terminal; in the processing flow of the service flow, the IPv4 service message is sent to the single-board, which has the address pool that includes the destination IPv4 address, to process; and the IPv6 service message is sent to the single-board, which matches the destination IPv6 address prefix, to process. By employing said method, the decision, whether to perform NAT-PT, and message load-sharing are completed at the same time. Therefore, the wasting of computing resource is avoided. In said device, the address pool resource in each of single-boards is different, the NAT-PT mapping list created in every single-board is independent of each other, and the same service flow is sent to the same processing single-board. Therefore, the wasting of storage resource is avoided.

Description

NAT-PT device and load sharing method thereof

Technical field

The present invention relates to network communication, and in particular to a NAT-PT (Network Address Translation - Protocol Translation) network for interworking between IPv6 (Internet Protocol Version 6) single protocol network and IPv4 (Internet Protocol Version 4) single protocol network. Address translation - protocol conversion) device and its load sharing method.

Background technique

The successful use of the TCP/IP protocol cluster has led to the rapid development and widespread application of communication technologies. As the core protocol of the network technology, the IPv4 protocol suffers from the limitation of the 32-bit address length, and the address allocation is about to be exhausted and difficult to expand. . To overcome the limitations of the existing IPv4 protocol suite, an IPv6 protocol with unlimited address resources and good scalability has been proposed and has been applied. However, the transition from IPv4 to IPv6 will take a considerable period of time. During the transition period, communication between various devices in the IPv4 single-protocol network domain and the IPv6 single-protocol network domain is required. IPv4 packets need to be completed on the border routers of the IPv4 network and the IPv6 network. The conversion between the text and the IPv6 packet. The router with this function is also called the NAT-PT gateway, which is used to implement the communication between the IPv4 single protocol domain and the IPv6 single protocol domain terminal. On the other hand, the number of rapidly increasing users and the bandwidth requirements of services for data services are increasing. To meet the needs of continuous expansion, most of the current communication devices adopt a distributed system architecture, which is generally handled by interface boards and control planes. The board and the data processing board are composed. The interface board is responsible for receiving packets, separating control signaling, and user data from the external port, and distributing them to the control plane processing board and the data processing board. The receiving board is also processed by the control plane processing board or the data processing board. The packet is sent out through the interface. Because there are multiple processing boards in a distributed device, how to implement load sharing (or load balancing) between multiple processing boards is a very important aspect of system design. For distributed NAT-PT devices, load balancing mainly refers to the following two aspects: 1) How to distribute packets that need to be NAT-PT to multiple NAT-PT processing boards for NAT-PT processing; 2) The address pool resource configured for the NAT-PT device and the address mapping table used for packet conversion are balanced on multiple NAT-PT processing boards. In the prior art, the load sharing of the packet processing in the distributed NAT-PT device generally uses a load sharing scheme commonly used in the distributed network device: First, the header information of the packet is extracted by the packet header information extracting unit, such as the source IP. , destination IP, protocol type, 4-layer port number information, etc., and then the distribution unit constructs the information as a decision and distribution index key according to a certain rule, and then hashes or models the index key. Therefore, the packets are distributed to different processing boards. FIG. 1 is a schematic diagram showing the principle of implementing distributed load balancing of a distributed NAT-PT device by using the technical solution. The index key composed of multiple fields in the header of the message is used for packet distribution by hashing or modular operation. The method has the following problems:

1. If there is a field change in the multiple fields of the index key, the message will be distributed to different NAT-PT processing boards, so that the same user or the same service flow will be It is distributed to different NAT-PT processing boards. This requires that all NAT-PT boards must reside in all address pool resources, which may result in the generation of all the same mapping table entries, resulting in waste of storage resources of each processing board. In some cases it is even difficult to achieve;

2. The index key is constructed by using multiple fields in the IP packet header. Especially for IPv6 packets, the index length is too long. The hash operation requires more computing resources, especially when the software is implemented. Summary of the invention

The technical problem to be solved by the present invention is to provide a NAT-PT device and a load sharing method thereof, which can effectively reduce the load of each processing board and avoid waste of storage resources.

In order to solve the above technical problems, the present invention is achieved by the following technical solutions:

(-) A load sharing method for a NAT-PT device, the method comprising the following steps:

A. Configure different NAT-PT IPv6 prefixes and IPv4 address pool resources for each NAT-PT processing board in the NAT-PT device.

B. The source terminal initiates the domain name resolution process, and sends the domain name resolution request packet poll to different

After the processing is completed, the processing is sent to the destination terminal. After the destination terminal returns the domain name resolution response packet, the destination terminal sends the packet to the NAT-PT processing board that processes the request packet. After sending to the source terminal; C. The service flow processing process between the source terminal and the destination terminal is performed, and the IPv4 service packet is sent to the NAT-PT processing board to which the address pool containing the destination IPv4 address belongs, and the IPv6 service packet is sent to The NAT-PT processing board that matches the destination IPv6 address prefix is processed.

The source terminal is an IPv4 terminal, and the destination terminal is an IPv6 terminal; or the source terminal is an IPv6 terminal, and the destination terminal is an IPv4 terminal.

In the step A, a NAT-PT IPv6 prefix and an IPv4 address pool are configured for each NAT-PT processing board, and the service packet is subjected to NAT-PT processing in the step C.

In the step A, two NAT-PT IPv6 prefixes are configured for each NAT-PT processing board, and the IPv4 address pool is divided into two parts including a port number and a port number, respectively. The two prefixes correspond.

The processing of the domain name resolution request packet and the response packet by the NAT-PT processing board includes the NAT-PT processing and the domain name resolution processing.

In the step C, if the address pool matching the destination IPv4 address does not include the port number, the NAT-PT processing board performs NAT-PT processing on the packet, otherwise the NAPT-PT (Network Address) is performed. Port Translation - Protocol Translation: Network address port translation - protocol conversion processing; For IPv6 packets, if the address pool corresponding to the matching prefix does not include the port number, NAT-PT processing is performed on it, otherwise NAPT-PT is performed. deal with.

(=) A NAT-PT device includes an interconnected interface board and a NAT-PT processing board, the interface board includes an interconnected interface unit and a decision distribution unit, and the NAT-PT processing board includes Interconnected NAT-PT processing unit and resource management unit, where:

The interface unit is configured to receive and send IPv4 and IPv6 packets;

The decision distribution unit is configured to send the domain name resolution message polling to the NAT-PT processing board; determine the NAT-PT processing board that matches the destination IPv6 address prefix or the destination IPv4 address of the service packet, and report the service The document is distributed to the matching NAT-PT processing board;

The NAT-PT processing unit is configured to process the packet;

The resource management unit is configured to manage an IPv4 address pool, a port, and a NAT-PT IPv6 prefix resource of the NAT-PT processing board. The NAT-PT processing unit performs NAT-PT processing and domain name resolution processing on the domain name resolution packet, and performs NAT-PT processing or NAPT- on the service packet according to the IPv6 prefix of the packet or the IPv4 address pool to which the destination address belongs. PT processing.

The NAT-PT processing board further includes a storage unit, configured to store an IPv4 address pool, a port, and a NAT-PT IPv6 prefix resource of the NAT-PT processing board.

The device further includes a control plane processing unit and a route forwarding engine unit, where the control plane processing unit is configured to process control plane commands and messages that enter the device;

The routing and forwarding engine unit is configured to complete routing and forwarding of packets.

The invention has the following beneficial effects:

The present invention configures a prefix and an address pool resource for each NAT-PT processing board to perform NAT-PT decision-making and packet load balancing at the same time. For IPv6 to IPv4 packets, decision-making and load sharing are performed. Only the upper 96 bits of the destination V6 address are used to directly match the prefixes configured by the NAT-PT processing board. This avoids the waste of computing resources. For IPv4 to IPv6 packets, the destination IPv4 address and board configuration are used for decision-making and load balancing. On the other hand, the same service flow is distributed to the same processing board. The NAT-PT mapping table generated on each board is independent of each other. . DRAWINGS

FIG. 1 is a schematic diagram of a load sharing principle of a distributed NAT-PT device;

2 is a flowchart of a load sharing method of a NAT-PT device according to the present invention;

3 is a schematic diagram of a principle of a load sharing method according to Embodiment 1;

4 is a flowchart of a method for determining and distributing the first embodiment;

FIG. 5 is a flowchart of a method for processing a NAT-PT board according to Embodiment 1;

Figure 6 is a structural diagram of a distributed NAT-PT device of the present invention. detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: The present invention provides a load sharing method for a NAT-PT device. As shown in FIG. 2, the method includes the following steps:

201. Configure different NAT-PT IPv6 prefixes and address pool resources for each NAT-PT processing board.

202. The source terminal initiates a DNS (Domain Name Resolution) process, and sends a DNS request packet to a different NAT-PT processing board for processing, and then sends the packet to the destination terminal. After the destination terminal returns the DNS response packet, the destination terminal sends the DNS response packet to the destination terminal. The packet is sent to the NAT-PT processing board that processes the request packet for processing, and is sent to the source terminal after processing.

203. Enter a service flow processing process between the source terminal and the destination terminal, and send the IPv4 service packet to the NAT-PT processing board to which the address pool containing the destination IPv4 address belongs, and send the IPv6 service packet to the same. The NAT-PT processing board that matches the destination IPv6 address prefix is processed.

Embodiment 1:

Generally, the NAT-PT device provides communication between the IPv4 single protocol domain and the terminal in the IPv6 single protocol domain. The session may be initiated by the IPv4 domain terminal or by the IPv6 domain terminal. Therefore, the source terminal in the foregoing method is an IPv4 domain terminal or an IPv6 domain terminal. The destination terminal is an IPv6 domain terminal or an IPv4 domain terminal. FIG. 3 is a schematic diagram of the principle of the load sharing method in the embodiment, and can also be regarded as a schematic diagram of a logical implementation unit of the distributed NAT-PT device.

The unit 301: for the IPv6 packet, the upper 96 bits of the destination address of the IPv6 packet are used for the prefix matching. For the IPv4 packet, the destination address of the IPv4 packet is extracted by the unit 302 for range matching.

The unit 302 is configured to match the extracted prefix information or the IPv4 address and the load sharing table to determine whether the packet is subjected to NAT-PT processing, and the load is shared to different NAT-PT processing boards.

Unit 303: Load Sharing Table, Maintaining NAT - PT IPv6 Prefix, Address Pool, and NAT -

The correspondence between the PT processing boards, that is, the load sharing strategy.

Unit 304: NAT - PT processing board, responsible for NAT-PT processing of packets, management of address pool and port; including NAT - PT processing unit (including DNS - ALG ( Domain Name Service Application Level Gateway: Domain Name Resolution Service (application level gateway) processing), address pool and port management unit.

The following describes the decision-making and load-sharing methods used in this embodiment in the case where the session is initiated by an IPv4 domain terminal or initiated by an IPv6 domain terminal:

Pre-conditions: Configure different NAT-PT IPv6 prefix information and address pool resources for each NAT-PT processing card. For a NAT-PT device, the DNS-ALG needs to be implemented. When the source initiates a session, the source first initiates a DNS process. In particular, for the IPv4 source to initiate a session, the DNS process must be initiated first.

Referring to FIG. 4 and FIG. 5, the specific process of initiating a session by an IPv4 terminal is as follows:

A1: The IPv4 terminal initiates the DNS process. The IPv4 address of the packet is configured as <source: IPv4 domain DNS server address. Purpose: IPv4 address is the IPv4 address of the IPv6 domain DNS server>. This address is in the address pool configured by the NAT-PT device. Within the scope, and for load sharing, this address is required to be statically configured on each processing board.

A2: The IPv4 DNS request packet is sent to different boards for NAT-PT and DNS-ALG processing, and then sent to the IPv6 domain DNS server. Assume that the packet is distributed to the board 1 and the packet IPv6 address is formed. For <source: prefix 1 + IPv4 domain DNS server address, destination: IPv6 domain DNS server IPv6 address>.

A3: IPv6 domain DNS response packet, the upper 96 bits of the IPv6 destination address are prefixed with 1 and are distributed to the board 1 for NAT-PT processing and DNS-ALG processing. In this case, the IPv6 address is assigned to the IPv6 terminal. 1 address pool, recorded as IPv4 - 1) and port number, generate corresponding mapping table entries, and finally send to the IPv4 terminal.

A4: Enter the service flow processing process between the IPv4 terminal and the IPv6 terminal. For the service packets sent by the IPv4 terminal, the destination IPv4 address is IPv4 - 1 and is distributed to the board 1 for NAT-PT processing and then to the IPv6 terminal. For the service packets sent by the IPv6 terminal, the destination IPv6 address is high. The 96-bit prefix 1 is distributed to the corresponding board 1 for NAT-PT processing.

Referring to FIG. 4 and FIG. 5, the specific process of initiating a session by an IPv6 terminal is as follows:

B1: The IPv6 terminal first initiates the DNS process. At this time, the IPv6 address of the packet is composed of <source: IPv6 domain DNS server address; destination: common prefix + IPv4 domain DNS server address>. B2: The IPv6 DNS request packet is sent to a different NAT-PT board for processing (assuming it is sent to the board 2), and an IPv4 address is assigned to the IPv6 DNS server (belonging to the board 2, denoted as IPv4 - 2) and The port number is sent to the IPv4 domain DNS server after the NAT-PT is processed.

B3: IPv4 DNS response packet, the destination address is IPv4- 2, so it is distributed to the corresponding NAT-PT processing board 2 and finally sent to the IPv6 terminal. The processed packet IP address is composed of <source: prefix 2 + IPv4 domain DNS server address, destination: IPv6 domain destination DNS server address>.

B4: Enter the service flow processing process between the IPv4 terminal and the IPv6 terminal. For the service packets sent by the IPv6 terminal, the upper 96 bits of the destination IPv6 address are prefix 2, so they are distributed to the corresponding NAT-PT board 2 for NAT-PT processing. At this time, the V4 address and port number are assigned to the IPv6 terminal. The mapping table information is generated and sent to the IPv4 terminal after the processing is complete. The IPv4 address is sent to the NAT-PT board 2 for NAT. - PT processing, then sent to the IPv6 terminal.

Embodiment 2:

In the first embodiment, an independent prefix and a different address pool resource are configured for each NAT-PT board. The 96-bit prefix matching and the IPv4 destination address matching of the IPv6 destination address are only used to determine whether the packet needs to be processed. After the service packet is distributed to the NAT-PT processing board, the decision message is required to be NAT-PT or NAPT-PT. This embodiment is based on the solution of the first embodiment. The extension can determine the type of processing (NAT-PT processing and NAPT-PT processing) at the same time in decision-making and load sharing, so that the performance of the device can be further provided. The specific expansion scheme is as follows:

(1) Configure two NAT-PT IPv6 prefixes for each NAT-PT processing board. The prefix A corresponds to NAT-PT processing and the prefix B corresponds to NAPT-PT processing.

(2) The address pool resources configured on each NAT-PT processing board are divided into two parts: address pool A, which is used only for NAT-PT processing, and does not use ports; address pool B, port number, used for NAPT - PT processing.

(3) When the NAT-PT device allocates the address and port, if the address pool A is selected, the prefix A is used in the process. If the address pool B is selected, the prefix B is used in the process. Decision Policy distribution is based on different address pool matching and prefix matching to determine NAT-PT decision, type differentiation, and load sharing.

The present invention also provides a NAT-PT device. As shown in FIG. 6, the interface includes multiple interface boards and multiple NAT-PT processing boards. The interface board and the NAT-PT processing board communicate through the bus. The interface board includes an interconnected interface unit and a decision distribution unit, and the NAT-PT processing board includes an interconnected NAT-PT processing unit and a resource management unit.

The interface unit is configured to receive and send IPv4 and IPv6 packets. The decision distribution unit is configured to send the DNS packet to the NAT-PT processing board; determine the NAT-PT processing board that matches the destination IPv6 address prefix or the destination IPv4 address of the service packet, and distribute the service packet to the service packet. The matching NAT-PT processing board. The NAT-PT processing unit is used to process the message. The resource management unit is used to manage the address pool, port, and NAT-PT IPv6 prefix resources of the NAT-PT processing board.

The NAT-PT processing board of the distributed NAT-PT device may further include a storage unit for storing an address pool, a port, and a NAT-PT IPv6 prefix resource of the NAT-PT processing board. The device may also include a control plane processing unit (for handling control plane signaling and messages entering the device), a routing and forwarding engine unit (for routing and forwarding of messages), and the like.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

Claim

A load sharing method for a NAT-PT device, characterized in that the method comprises the following steps:

B. The source terminal initiates the domain name resolution process, and sends the domain name resolution request packet to the different NAT-PT processing boards for processing. After the processing is completed, the destination terminal sends the domain name resolution response message to the destination terminal. The message is sent to the NAT-PT processing board that processes the request packet for processing, and is sent to the source terminal after processing;

C. The service flow processing process between the source terminal and the destination terminal is performed, and the IPv4 service packet is sent to the NAT-PT processing board to which the address pool containing the destination IPv4 address belongs, and the IPv6 service packet is sent to The NAT-PT processing board that matches the destination IPv6 address prefix is processed.

The load sharing method according to claim 1, wherein the source terminal is an IPv4 terminal, and the destination terminal is an IPv6 terminal; or the source terminal is an IPv6 terminal, and the destination terminal is an IPv4 terminal. .

The load sharing method according to claim 2, wherein in the step A, each NAT-PT processing board is configured with a NAT-PT IPv6 prefix and an IPv4 address pool, and in step C, Service packets are processed by NAT-PT.

The method of load balancing according to claim 2, wherein in the step A, two NAT-PT IPv6 prefixes are configured for each NAT-PT processing board, and the IPv4 address pool is divided into ports. The two parts of the number and the port number are not included, respectively, corresponding to the two prefixes.

The load balancing method according to claim 3 or 4, wherein in the step B, the processing of the domain name resolution request message and the response message by the NAT-PT processing board includes NAT-PT Processing and domain name resolution processing.

The load sharing method according to claim 4, wherein in the step C, For an IPv4 packet, if the address pool matching the destination IPv4 address does not include the port number, the NAT-PT processing board performs NAT-PT processing on it, otherwise it performs NAPT-PT processing. For IPv6 packets, if it matches If the address pool corresponding to the prefix does not include the port number, NAT-PT processing is performed on it, otherwise NAPT-PT processing is performed.

A NAT-PT device, comprising: an interconnected interface board and a NAT-PT processing board, wherein the interface board includes an interconnected interface unit and a decision distribution unit, and the NAT-PT processing The board includes an interconnected NAT-PT processing unit and a resource management unit, where: the interface unit is configured to receive and send IPv4 and IPv6 messages;

The decision distribution unit is configured to send the domain name resolution message polling to the NAT-PT processing board, and determine the NAT-PT processing board that matches the destination IPv6 address prefix or the destination IPv4 address of the service. The packet is distributed to the matching NAT-PT processing board; the NAT-PT processing unit is configured to process the packet;

The resource management unit is configured to manage an IPv4 address pool, a port, and a NAT-PT IPv6 prefix resource of the NAT-PT processing board.

The NAT-PT device according to claim 7, wherein the NAT-PT processing unit performs NAT-PT processing and domain name resolution processing on the domain name resolution packet, according to the prefix of the packet IPv6 or its destination address. The IPv4 address pool belongs to NAT-PT processing or NAPT-PT processing.

The NAT-PT processing device according to claim 8, wherein the NAT-PT processing board further includes a storage unit, configured to store an IPv4 address pool, a port, and a NAT-PT of the NAT-PT processing board. IPv6 prefix resource.

The NAT-PT device according to claim 7, 8 or 9, wherein the device further includes a control plane processing unit and a route forwarding engine unit, where

The control plane processing unit is configured to process a control plane command and a message that enters the device. The route forwarding engine unit is configured to complete routing and forwarding of the packet.