KR20020034280A - A NAT Table Structure for effective searching and management of NAT Table in PC - Google Patents

Abstract

PURPOSE: A NAT(Network Address Translation) table structure and a method for the effective NAT table management and search on the PC environment are provided to offer the effective data speed to a user of a client PC and to rapidly search the client PC information stored in a NAT table while utilizing the maximum performance of a NAT server PC and the client PC through the effective management of the NAT. CONSTITUTION: The NAT table structure includes a common part table including a client common part table(320) storing/managing the common information of the client PC and a server common part table(330) storing/managing the common information of a local server PC, a TCP(Transmission Control Protocol) part table including a client TCP part table(340) storing the TCP information of the client PC and a server TCP part table(350) storing the TCP Information of the local server PC, a UDP(User Datagram Protocol) part table including a client UDP part table(360) storing the UDP information of the client PC and a server UDP part table(370) storing the UDP Information of the local server PC, and a client ICMP(Internet Control Message Protocol) part table storing the ICMP information of the client PC.

Description

NAT table structure for effective searching and management of NAT table in PC

The present invention relates to a NAT table structure and method for efficient network address translation (NAT) table management and retrieval in a PC environment. In particular, multiple users can access an Internet by sharing one IP (Internet Protocol) address in a general PC. Efficient management of NAT, which is a type of address sharing mechanism that makes the most of the performance of NAT server PCs and client PCs, provides efficient data rates for users who use client PCs, and allows you to quickly retrieve information from client PCs stored in NAT. NAT table structure and method for efficient NAT table management and retrieval in PC environment.

In general, a conventional NAT table is not only complicated and difficult to manage because there is too much information to store for one client PC, but also a waste of PC resources and a lot of information elements of a client PC stored in a NAT table. In order to deliver the Internet data to the client PC correctly after the internet connection, there was a disadvantage that the data rate becomes slow due to the search delay when searching the NAT table.

Accordingly, the present invention has been made to solve the above problems, NAT server PC and client by efficient management of NAT which is a kind of address sharing mechanism that allows multiple users to access the Internet by sharing a single IP address in a general PC NAT table structure and method for efficient NAT table management and retrieval in PC environment that can maximize the performance of PC and provide efficient data rate to users who use client PC and can quickly retrieve information of client PC stored in NAT. The purpose is to provide.

1 is a typical NAT network configuration according to the present invention,

2A is a structural diagram of a NAT common part table according to the present invention;

2b is a NAT TCP parts table structure diagram according to the present invention;

2c is a NAT UDP part table structure diagram according to the present invention;

2d is a NAT ICMP parts table structure diagram according to the present invention;

3 is a NAT table search and management scheme according to the present invention;

4 is a NAT table management flowchart according to the present invention;

5 is a flow chart illustrating a NAT table entry search in accordance with the present invention.

* Description of the main symbols in the drawings

210: NAT Common Part Table 220: NAT TCP Part Table

230: NAT UDP Part Table 240: NAT ICMP Part Table

320: NAT Client Common Part Table 330: NAT Server Common Part Table

340: NAT Client TCP Part Table 350: NAT Server TCP Part Table

360: NAT Client UDP Part Table 370: NAT Server UDP Part Table

380: NAT Client ICMP Part Table

In order to achieve the above object, NAT table structure and method for efficient NAT table management and retrieval in the PC environment according to the present invention is a personal network (PC) users a number of private network IP (Internet Protocol) to a global network A method of managing information of client PC users when receiving a data service using an IP address conversion technology (NAT), comprising: a first step of analyzing data received from a client PC by the NAT table manager; A second step of newly creating an entry suitable for a NAT table component when the analyzed data is first input from a client PC; A third step of retrieving the newly created entry from an address translator and storing the newly created entry in a NAT table for transmission to the corresponding destination exactly; And a fourth step of deleting unnecessary entries from the NAT table according to the termination of the service provided from the client PC among the stored entries.

In the address translation technology for converting multiple private network IPs into one global network IP, a system identifier, a client common part table for storing and managing common information of a client PC, and a server for storing and managing common information of a local server PC A common part table, including a common part table; A TCP part table including a client TCP part table for storing Transmission Control Protocol (TCP) information of a client PC, and a server TCP part table for storing TCP information of a local server PC; A UDP part table including a client UDP part table for storing UDP (User Datagram Protocol) information of a client PC, and a server UDP part table for storing UDP information of a local server PC; And an ICMP parts table including a client ICMP parts table for storing ICMP (Internet Control Message Protocol) information of the client PC.

A method of retrieving an entry from a NAT table when a client PC requests a connection to a NAT server PC, the method comprising: a first step of extracting information for retrieving a NAT table by analyzing a arrived packet header; Determining whether the packet is a service request for a client PC or a local server PC using the extracted information; A third step of requesting a NAT table for the client PC if the determination is a service request for the client PC; A fourth step of comparing the entry stored in the requested NAT table with the packet header information analyzed in the first step; And compares the entry, and if there is an entry matching the analysis packet header information, updates the entry information in the NAT table and performs address translation for transmitting and receiving packets; if there is no match, performing a NAT entry allocation algorithm to allocate a new entry. And a fifth step of performing address translation after storing the analysis packet header information in a NAT table.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a typical NAT network configuration according to the present invention, and includes a service relay system 110 installed in an operator network and an indoor system 120 installed in a subscriber's home. The service relay system 110 separates data and voice and transmits the data and voice to the data communication network 104 and the public telephone network (PSTN) 106, respectively. The indoor system 120 includes a NAT server PC 121 equipped with a NAT, a hub (123), and a client PC (125a to 125n) equipped with a public telephone network through a single telephone line or coaxial cable. In this way, the computer can be connected to the data network at the same time. NAT server PC is equipped with LAN (Local Area Network) card to connect with client PC and WAN (Wide Area Network) or LAN card to connect with data network. Global IP, Private IP for LAN card of client PC is used, and it is a device that performs the basic function of NAT to store and manage information of client or local server PC. In addition, the hub is an Internet multiport providing device that connects n client PCs to one NAT server PC, and the client PC uses a private IP with a LAN card as standard to connect to the NAT server PC. There are up to n depending on the ability. In general, address translation technology (NAT) is a function that converts an IP address of a private network into a global network IP address by using an address assignment mechanism. The IP address is embedded in a router or a firewall. It is used for the purpose of saving. In other words, NAT is a technology that performs IP address translation to change the number of PCs with each private IP connected to the internal network to one authorized IP address to receive Internet service.

2A to 2D are diagrams illustrating NAT table structures according to the present invention, in which a common part table (210) common to all services and a TCP part table 220 classified according to protocol types and a user datagram protocol (UDP) protocol are illustrated. Including the UDP part table 230 for processing, and the Internet Control Message Protocol (ICMP) part table 240 for processing a control message (CM), the information of the client PC is first obtained according to a service request from the client PC. Information stored on the client PC is stored and managed in an order of storing the corresponding information in the protocol table by dividing the protocol type.

FIG. 2A is a structure diagram of a NAT Common Part Table according to the present invention, in which a system is an element for identifying whether information on a client PC of a private network or information on a local server is required, and an index is a NAT. Pointer to an entry, incremented by one up to the maximum available entry whenever a NAT entry is used for the client PC or local server. Empty is an element that indicates whether entries in the NAT table are currently being used for entry allocation or not, and OrgSrcAddr (Original Source Address) delivers the data exactly to the client PC after the client PC is connected to the data network. OrgDstAddr (Original Destination Address) is an element used to check whether it is a response from an ISP (Internet Service Provider) in a data network for a request of a client PC. The Time Stamp is a time management element necessary to calculate the time duration of a service that obtains the time of a system equipped with NAT and allocates a new time every time a client PC requests a service using NAT. Live) means the duration of the service currently being provided. If the currently provided service is out of the TTL standard value, the service is stopped. Finally, Protocol is an element that indicates which protocol the current service uses. Depending on the protocol, it uses TCP Part Table, UDP Part Table, and ICMP Part Table, which can manage NAT table management without any complexity. Make sure

Figure 2b is a NAT TCP Part Table structure diagram according to the present invention, SeqAck (Sequence and Acknowledgement) is a factor for ensuring the data order when transmitting and receiving data over a TCP connection, which is a receiver that the size and order of the data transmitted by the transmitter In this case, the receiver correctly transmits the data to the transmitter by transmitting a message indicating that the data has been well received and the next message to be received, thereby enabling accurate transmission and reception of data. In addition, OrgSrcPort (Original Source Port) is an element used to accurately transfer data to the service of the corresponding port of the client PC after the service requested by the client PC is connected to the data network, and OrgDstPort (Original Destination Port) is the client. This element is used to check whether the PC responds to a request for service from the ISP of the destination port in the data network. NewSrcPort (New Source Port) is a new port of a client PC for address translation within a NAT server PC that is used by a client PC to connect to the data network through a NAT server PC and then to identify the NAT server PC from the ISP of the data network. . Finally, Flag is an element for the control message used to connect, maintain, or terminate TCP. This indicates whether the use of TCP is for initial phase setting, sending and receiving messages, or terminating TCP connection. Is displayed.

FIG. 2C is a structure diagram of a NAT UDP Part Table according to the present invention, which is similar to the NAT TCP Part Table of FIG. 2B. However, in the UDP TCP Part Table, since the network connection method is connectionless and the data transmission method is a datagram method. The SeqAck element and the Flag element are not used. The remaining elements are identical.

2d is a NAT ICMP Part Table structure diagram according to the present invention, where OldID (Old Identification) is an element for identifying a client PC that initially sent a control message using ICMP, and NewID (New Identification) is a client PC using ICMP. A new ICMP ID of the client PC for address translation within the NAT server PC that is used to send a control message to the system through the NAT server PC and then to verify the NAT server PC for a response from the system.

3 is a schematic diagram of a NAT table search and management according to the present invention, in which information of a client PC is stored when the client PC uses NAT, or an actual table management scheme. The common part table 210 of FIG. 2A is a system identifier. (310) C-Common (Client Common) Part Table (320) for storing and managing common information of the client PC and S-Common (Server-Common) Part Table (330) for storing and managing common information of the local server PC. ). The TCP Part Table 220 of FIG. 2B includes a Client-TCP Part Table 340 for storing TCP information of a client PC and a Server-TCP Part for storing TCP information of a local server PC. Table 350 is included. In addition, the UDP Part Table 230 of FIG. 2C includes a Client-UDP (C-UDP) Part Table 360 storing UDP information of a client PC and an S-UDP (Server-UDP) storing UDP information of a local server PC. A Part Table 370 is included, and the ICMP Part Table 240 of FIG. 2D includes a Client-ICMP (C-ICMP) Part Table 380 that stores ICMP information of a client PC. The system identifier 310 distinguishes whether a packet is information for a client PC of a private network or a information of a local server PC in a private network when a packet comes in from the inside or the outside, and if it is information of a client PC, the C-Common Part Table 320 Otherwise, the pointer is passed to the S-Common Part Table (330). Each table that receives the pointer sets, retrieves, or deletes the information corresponding to the table entry according to the contents of the received packet, and at the same time, the corresponding protocol table, that is, C (S) -TCP, C (S) -UDP, C- By searching for one of the ICMP Part Tables and setting information in the Table Entry, or performing search and deletion, overall management of the NAT Table is performed as shown in the Table system of FIG. 3 based on FIGS. 2A to 2D.

4 is a NAT table management flowchart according to the present invention. For efficient use and management of NAT, it is divided into NAT Table Initiator, NAT Table Manager, and Address Translator. Specifically, NAT Table Manager consists of Entry Creation, Storage, and Deletion. It consists of a retrieval unit for retrieving and a NAT entry allocator for initial NAT users, a translator that replaces the IP of the private network and the global network, and a NAT entry revocation unit upon termination of NAT. NAT, which consists of table initialization, management, and transformation, is initiated when the server PC equipped with NAT initializes the Network Adapter at initial boot-up or by initializing the table by NAT Manager, and the rest of the configuration is actually performed by the client PC user. This is done when you want to access the Internet via a server PC. In the NAT table management method, the NAT table management unit analyzes data received from the client PC or the Internet (s1), and if the analyzed data is data received for the first time from the client PC, the NAT table management unit applies a new NAT entry to fit the NAT table component. Create new (s2). Then, the newly created entry is searched by the address translator and stored in the NAT table for transmission to the corresponding destination (s3), and unnecessary entries are deleted from the stored NAT entries (s4).

FIG. 5 is a flowchart illustrating a NAT table entry search according to the present invention, that is, a flowchart of NAT table search when a client PC requests a connection to a NAT server PC. First, when a packet arrives from the client PC to the NAT server PC, it analyzes the packet IP header and the TCP or UDP header and extracts the information for NAT table search (s11). Check whether the service request or the service request for the local server PC (s12). If it is a packet of a service request using TCP of the client PC, the NAT table for the client PC is searched (s13); otherwise, the NAT table of the local server PC is searched. When searching the NAT Table, the entries stored in the NAT Table are compared with the extracted information by using the extracted TCP / IP Header information, that is, the Original Source Address, Original Destination Address, Original Source Port, and Original Destination Port. The NAT table is sequentially searched to see if an entry of the packet exists in the NAT table (S14). If there is a corresponding entry in the NAT table that matches the above information, the information of the entry in the NAT table is updated (s15), and address translation is performed for accurate packet transmission and reception (s16). If no matching entry is found in the NAT table, the NAT Entry Allocation Algorithm, which is part of the address translation algorithm, is performed (s17), a new entry is allocated (s18), and the information about the packet is stored in the NAT Table (s19). Perform the conversion (s20).

As described above, NAT table structure and method for efficient NAT table management and retrieval in PC environment are not only PC environment but also UNIX, regardless of LAN, ADSL, UADSL, Dial-up modem, ISDN, Cable modem, or leased line. Simple and accurate table configuration in the environment can minimize the resource usage of the server PC equipped with NAT, and efficiently store and manage the information of the client PC users using NAT, and is an economical and optimal service for the client PC users. Can be provided. In other words, by optimizing the NAT table structure, it reduces the load on the NAT server PC and prevents delays in retrieving user information, thereby providing fast services such as using global IP to clients using private IP, as well as efficient user information management. There is an effect that can improve the quality of data service.

Claims (3)

When personal computer (PC) users are provided with data services using address translation technology (NAT), which converts multiple private network IPs (Internet Protocol) into one global network IP, In A first step of analyzing data received from a client PC in the NAT table management unit; A second step of newly creating an entry suitable for a NAT table component when the analyzed data is first input from a client PC; A third step of retrieving the newly created entry from an address translator and storing the newly created entry in a NAT table for transmission to the corresponding destination exactly; And And a fourth step of deleting unnecessary entries from the NAT table according to service termination provided from a client PC among the stored entries. In Address Translation Technology (NAT), which converts multiple private network IPs into one global network IP, A common part table including a system identifier, a client common part table for storing / managing common information of a client PC, and a server common part table for storing / managing common information of a local server PC; A TCP part table including a client TCP part table for storing Transmission Control Protocol (TCP) information of a client PC, and a server TCP part table for storing TCP information of a local server PC; A UDP part table including a client UDP part table for storing UDP (User Datagram Protocol) information of a client PC, and a server UDP part table for storing UDP information of a local server PC; And an ICMP parts table including a client ICMP parts table that stores Internet Control Message Protocol (ICMP) information of the client PC. In a method for retrieving an entry from a NAT table when a client PC requests a connection to a NAT server PC, A first step of extracting information for NAT table search by analyzing the arrived packet header; Determining whether the packet is a service request for a client PC or a local server PC using the extracted information; A third step of requesting a NAT table for the client PC if the determination is a service request for the client PC; A fourth step of comparing the entry stored in the requested NAT table with the packet header information analyzed in the first step; And If there is an entry matching the analyzed packet header information, the entry information in the NAT table is updated and address translation is performed to transmit and receive a packet.If there is no match, the NAT entry allocation algorithm is performed to allocate and analyze a new entry. And storing the packet header information in a NAT table and performing address translation.