KR20070076805A - Pc based wireless access points system by using network address transfer - Google Patents

Abstract

A PC(Personal Computer)-based wireless AP(Access Point) system using network address conversion is provided to use the wireless Internet only with a wireless LAN device and software, without the necessity of purchasing an expensive AP. A wireless Internet system using network address conversion comprises a user PC(100), a wireless LAN(500), and an application(600). The user PC, connected to the external wire/wireless Internet, serves as a gateway server. The wireless LAN connects the user PC with a client PC(200) through an infrastructure network. The application, installed in the user PC, executes the functions of an AP. The application allocates a private IP address, the gateway address and DNS address of the user PC, and a subnet mask to the client PC connected to the infrastructure network. In case the client PC uses the external Internet and transmits an Internet packet to the user PC, the application checks the Internet packet, records packet information, converts the client PC's MAC address and IP address into its own MAC address and IP address, and communicates with the Internet. If a communication result value is received, the application converts the converted addresses into the original addresses, based on the recorded Internet packet conversion information, and transmits them to the client PC.

Description

PC based Wireless Access Points System by using Network address Transfer}

1 is a schematic structural diagram of an embodiment of a wireless Internet system using network address translation;

2 is a configuration diagram of a wireless Internet system using a conventional infrastructure structure (infra structure) method,

3 is a detailed structural diagram of an embodiment of the application of FIG. 2;

4 is a flowchart illustrating a roaming method in which a client PC accesses a PC AP in a wireless Internet system using network address translation according to the present invention.

* Explanation of symbols for the main parts of the drawings

100: user PC 200: client PC

300: ad hoc network 400: Internet

500: WLAN device 600: Application

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wireless Internet systems using network address translation, and in particular, not a separate hardware access point (hereinafter simply referred to as an 'AP'), but a personal computer (hereinafter, simply referred to as a 'PC'). Wireless network in an infrastructure network consisting of a wireless LAN card supporting roaming in an infrastructure network and a PC AP composed of a wireless LAN installed in the PC and an application that performs the role of the AP. A wireless internet system using network address translation for implementing an internet implementation.

Currently, there are two types of wireless Internet, an infrastructure structure and an ad hoc method.

Wireless Internet, such as Nespot, which is well known to the general public, consists of an infrastructure network between a device called an AP and a general user PC. On the other hand, an ad hoc network is a basic unit of a WLAN and is a peer-to-peer method in which each user PC communicates with each other in an equal relationship without an AP. At this time, the communication area is referred to as a basic service set (hereinafter, simply referred to as 'BSS'), which is composed of only one BSS.

That is, the ad hoc network can communicate with each user's PC, but cannot use the internet to go out. In contrast, an infrastructure structure includes an extended service set in which one BSS is composed of an AP and a wireless Internet terminal, and a plurality of BSSs can be bundled and serviced by connecting an AP to a distribution system; Hereinafter, simply referred to as 'ESS').

2 is a block diagram of a wireless Internet system using a conventional infra structure.

As shown in the figure, the conventional wireless Internet system, through the AP (1), the Internet (2) connected through the AP (1) to enable the user PC to use the wireless Internet, through the AP (1) It comprises a plurality of user PC (3) to use the Internet and a wireless LAN (4) mounted on the user PC (3).

The user PC 3 connects to the AP 1 via the wireless LAN 4 to use the Internet 2, and this local network is composed of an infrastructure network.

However, the wireless Internet system as described above has a problem in that it is difficult to use for constructing a small wireless network because an expensive AP 1 must be purchased.

However, if an ad hoc network is used to construct a small wireless network, the Internet can be used inside the local network, but the Internet going to a wide area network (hereinafter simply referred to as WAN) is not available. Since it is impossible, it is inevitable to build a wireless LAN with an infrastructure (infra structure) network using the AP. Therefore, since the WLAN construction cost is high, it is a detrimental factor in the spread of the wireless Internet.

On the other hand, due to the small size and light weight of electronic products, 60% of the major electronic products are expected to be portable in 2006, and require a communication connection with other devices. Wireless communication is the motif of this integration, but on the contrary, it is a limitation due to limited communication resources. Constraints in limited bandwidth and terminal functions are bottlenecks in accommodating multimedia communication services provided in a wired environment. As a solution to the bottleneck, a short-range private wireless network for improving wireless access has recently attracted attention.

It is a low-cost device that is common in the common frequency band and is based on an ad hoc network which mainly aims to connect wired / wireless communication infrastructure and communication between devices. Therefore, in constructing a small wireless LAN, there is a demand for a technology that allows internal PCs connected to an access point to access a WAN and use the Internet without using a PC-based infrastructure network.

The present invention has been proposed in order to meet the above-described needs, overcomes the weakness of building an expensive access point by installing an application acting as an AP on the user PC, the PC connected to the PC-based access point is external It is an object of the present invention to provide a wireless Internet system using network address translation to enable the Internet.

The present invention for achieving the above object is to enable the at least one client PC to use the external Internet through a user PC in an infrastructure network that wirelessly connects at least one client computer (PC), A wireless Internet system using network address translation, the wireless Internet system comprising: the user PC connected with an external Internet, including wired / wireless, to perform a role of a gateway server; A WLAN for connecting the user PC and the client PC to an infrastructure network; And an application installed on the user PC to perform a function of an access point, wherein the application includes a private internet protocol (IP) address to the client PC connected to an infrastructure network, and a gateway of the user PC. Assigns an address and a domain name server (DNS) address, and a subnet mask, and if the client PC uses the external Internet and transmits the Internet packet to the user PC, examines this Internet packet and records the packet information, It converts the media access control (MAC) address and IP address of the client PC in the Internet packet header into the MAC address and IP address of the user PC and communicates with the Internet. When the communication result is received, the recorded Internet packet conversion information is recorded. Search and convert the original MAC address and IP address to the client PC Provides wireless Internet system using network address translation.

That is, according to the present invention, the wireless LAN device installed in the user PC is configured as an infrastructure network, and the other user PC configured as an infra structure network is connected to the user PC connected to the Internet, as well as an external network connection. By installing an application acting as an AP implemented to connect to a network and configuring the gateway server PC, and running the application installed in the server PC, another user PC connected to the infra structure network accesses the server PC, and the server PC The user's PC is connected to the internal and external network wirelessly to use the Internet, and as the user's PC moves, if the wireless reception rate drops below a certain level, it automatically connects to other server PCs configured by the present invention. You can roam to keep using the Internet.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same components have the same number as much as possible even if displayed on different drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic structural diagram of an embodiment of a wireless Internet system using network address translation.

As shown in the figure, the wireless Internet system of the present invention, the user PC 100 connected to the Internet 400, which serves as a gateway server in the infrastructure (300), infrastructure (infra structure) An infrastructure for wirelessly connecting a plurality of client PCs 200 and each client PC 200 to use the Internet 400 through the user PC 100 serving as a gateway server in the network 300. infrastructure 300, the user PC 100 acting as a gateway server, the Internet (including wired / wireless) 400 to enable the Internet, the user PC 100 and the client PC 200 (Infra structure) is connected to the network 300, the wireless LAN device 500 to enable roaming automatically when the client PC 200 is moved, installed in the user PC 100 that acts as a gateway server A It is configured to include an application 600 configured to perform the role of P.

The application 600 installed in the user PC 100 and acting as a gateway server may be a dynamic host configuration protocol (hereinafter referred to as simply referred to below) in a client PC 200 connected to an infrastructure network 300. Private Internet Protocol (hereinafter, simply referred to as 'IP') address, gateway address of user PC 100 and domain name server (hereinafter referred to as 'DNS') through the server function ')) Assigns an address and subnet mask.

In addition, when the client PC 200 uses the Internet 400 and transmits an Internet packet to the user PC 100, the client PC 200 examines the Internet packet to record packet information, and the Internet packet header Media access control (hereinafter, simply referred to as 'MAC') address and IP address of the client PC (200) to the user's PC (100) own MAC address and IP address to communicate with the Internet, When the communication result value is received, the recorded Internet packet conversion information is retrieved, converted to the original MAC address and IP address, and transmitted to the corresponding client PC 200 so that the Internet itself is in the infrastructure network. The client PC 200 does not allow the Internet.

The wireless LAN device 500 mounted on the user PC 100 and the client PC 200 to enable wireless Internet using an infrastructure network 300 may include a client PC 200. When moving, if the wireless reception rate is lower than the appropriate level, it can search the surrounding environment of the WLAN and automatically connect to the PC AP that provides the best wireless reception rate.It can be implemented in the device or installed as an application in the user PC. have.

* Figure 3 is a detailed structural diagram of an embodiment of the application of Figure 2, is installed in the user PC 100 is responsible for the function of performing the role of the AP.

As shown in the figure, the application 600 of the present invention, the roaming module 610, the association (association) module (615), network address translation (network address translation; hereinafter referred to simply as "NAT") module ( 620, an internet control message protocol (hereinafter simply referred to as ICMP) module 625, an address resolution protocol (hereinafter simply referred to as ARP) module 630, IP layer management module 635, network address port translation (hereinafter simply referred to as 'NAPT') module 640, DHCP server module 645, local network gateway server module 650, port forwarding Module 655, application layer gateway 660.

When the Internet packet comes from the client PC 200, the IP layer management module 635 examines the header of the incoming Internet packet, and if the packet type is IP, the NAT module 620, and in the case of ICMP, the ICMP module 625. In the case of ARP, the ARP module 630 is responsible for managing to hand over the packet to be processed.

When the destination of the Internet packet is an external network, the NAT module 620 converts the Internet packet into a source IP and MAC address of the user PC 100 having a public IP and transmits the packet. At this time, the NAPT module 640 records the corresponding work. When the Internet packet is received from the destination again, the work list is viewed, and the Internet packet is converted into the MAC address and the IP address of the client PC 200 to receive the Internet packet.

The Internet packet passing through the NAT module 620 converts the port information through the NAPT module 640, records the converted information, and performs the opposite operation when the packet comes in.

In general, when the Internet packet is sent from the client PC 200 to the external network, when the Internet packet returns, information to be returned is recorded and can be easily transmitted. However, if you want to connect to the client PC 200 in the internal network in the external network, that is, when a server such as a web server, FTP server in the client PC 200 in the internal network, the user PC ( Send an Internet packet.

However, at this time, the user PC 100 does not know whether to forward the corresponding Internet packet to the client PC 200 of the internal network. In order to solve these problems, a rule for sending an Internet packet to a specific user PC is provided. This problem can be solved by setting, and the module having such a function is the port forwarding module 655.

In addition, an application layer gateway server module 660 is a module that solves problems caused by non-standard communication protocols of various P2P applications.

In addition, the local network gateway server module 650 supports configuring multiple local networks through one network card.

4 is a flowchart illustrating a roaming method in which a client PC accesses a PC AP in a wireless Internet system using network address translation according to the present invention.

As shown in the figure, first, the client PC 200 searches for a surrounding WLAN environment when the wireless reception rate decreases, selects a PC AP having the best wireless reception sensitivity, and requests a connection to the selected PC AP. At this time, a security audit and authentication is performed between the PC AP and the client PC 200 to determine the use permission of the client.

When the security audit and authentication is successfully completed, the PC AP informs the client PC 200 the necessary information for using the Internet, such as a subnet mask, gateway address, IP address, DNS address, and the client PC 200 receives the received information. Set the network environment based on the background.

When the above process is completed, the client PC 200 is all ready to use the wireless Internet, it is free to use the wireless Internet.

Selecting and accessing a specific PC AP instead of roaming may be directly connected to a specific AP instead of automatically searching for an AP having the best wireless reception sensitivity in the above description.

When the client PC 200 searches for the surrounding WLAN environment, a protocol for distinguishing the PC AP from other PC PCs in the vicinity and selecting an optimal PC AP is required. When the ad hoc network is searched for the surrounding WLAN environment, the wireless reception rate between the client PC 200 and the wireless reception rate between the PC APs cannot be distinguished. Therefore, it is impossible to search for the optimized PC AP by applying the existing scheme. The PC AP discovery method may be implemented by defining various protocols.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes can be made in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

As described above, the present invention has the effect of enabling the wireless Internet to be used only with the wireless LAN device and software, without having to purchase an expensive AP for using the wireless Internet.

In addition, the present invention by assigning a private IP to the client PC connecting to the PC AP, there is an effect that the internal network is completely blocked by the external network to enhance the security.

In addition, since the present invention allocates a private IP to the client PC, there is an advantage that the cost of securing the public IP is not required.

In addition, the present invention uses an infrastructure (infra structure) network and uses a private IP, there is an effect that can be naturally extended to apply to the home networking market in the future.

In addition, the present invention by implementing the role of the AP in software, even if the WLAN specification changes in the future, there is an effect that can continue to use the wireless Internet only by purchasing a WLAN card.

Claims (2)

In a wireless Internet system using network address translation to enable at least one client PC to use the external Internet through a user PC in an infrastructure structure that wirelessly connects at least one client computer (PC) , The user PC connected with an external Internet, including wired / wireless, to serve as a gateway server; A WLAN for connecting the user PC and the client PC to an infrastructure network; And Installed in the user PC, the application for performing the function of the access point (AP) Including, but the application, Assigns a private Internet Protocol (IP) address, a gateway address and a domain name server (DNS) address, and a subnet mask of the client PC connected to the infrastructure network, and the client PC uses the external Internet. When the Internet packet is sent to the user's PC, the Internet packet is examined and the packet information is recorded, and the media access control (MAC) address and the IP address of the client PC in the Internet packet header are set to the MAC address and IP of the user's own PC. A wireless Internet system using a network address translation that communicates with the Internet by changing an address, retrieves the recorded Internet packet conversion information, converts the original MAC address and IP address, and sends the same to the client PC. The method of claim 1, The application, An IP layer management module for inspecting the header of the Internet packet when receiving the Internet packet from the client PC and transmitting the packet to the network address translation (NAT) module if the packet type is IP; The Internet packet is converted into a source IP and a MAC address of the user PC having a public IP and transmitted. When the Internet packet is received from a destination, the Internet packet is converted into a MAC address and an IP address of the client PC and transmitted to the client PC. NAT module; And Network address port translation (NAPT) module for converting port information of the Internet packet received from the NAT module and the destination, and recording the conversion information Wireless Internet system using the network address translation, comprising a.

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