KR20020036165A - Method for data communications on Internet using NAT and apparatus thereof - Google Patents

Abstract

PURPOSE: A method for a data communication applying a network address conversion technique on the Internet and a device thereof are provided to prevent the generation of a case which can not receive data normally when multimedia data including a voice are transmitted/received on an Internet network including a router applying a network address conversion technique. CONSTITUTION: In a method for communicating a router connected with a plurality of users to a server connected through a communication network, a non-licensed IP address and port is allocated to a user computer which requests an Internet connection out of the user computers(101). The non-licensed IP address and port is converted into a licensed IP address and port(103). The non-licensed IP address and port and the licensed IP address and port corresponded thereto are stored(105). An identification packet including the non-licensed IP address and port and a user ID and the licensed IP address and port are transmitted to the server(107). Data being transmitted by the server recognizing the non-licensed IP address and port and the licensed IP address and port corresponded thereto are transmitted to the user computer in accordance with the identification packet and the licensed IP address and port(109).

Description

Data communication method and apparatus therefor with network address translation technology applied to the internet {Method for data communications on Internet using NAT and apparatus}

The present invention relates to an apparatus and method for preventing a case in which data cannot be properly received when transmitting and receiving multimedia data including voice in an internet network including a router to which a network address translation technology is applied. will be.

The current Internet Protocol (IP) uses IPv4, which has a 32-bit system of IP addresses. However, with the rapid increase in Internet users, IP address shortages are occurring. As a solution to this problem, it is proposed as an evolutionary set to improve the current IPv4. In IPv6, the 128-bit IP address is used to increase the absolute IP address, which is difficult to implement right now because the backbone equipment of networks around the world must meet this standard.

Thus, the proposed solution is a network address translation technique. This network address translation technique translates an IP address on an internal network that uses a different IP address than what is known on the external network. In other words, a private IP address (or private address) is used internally and the public IP address is used when the Internet is accessed. Typically, a company maps its internal network address to one or more IP addresses. It then converts the public IP addresses on incoming packets back to private IP addresses. This helps to ensure security issues because each outgoing or incoming request must go through an address translation process, and also provides an opportunity to limit or authenticate the request, and to match the previous request. NAT also preserves the number of public IP addresses required by the company and allows the company to use only one public IP address for communication with external networks. This NAT is described in the general agreement of RFC 1631 as a way to reduce the problem of IP address exhaustion.

However, some home users or companies do not have enough IP addresses to use this method.In this case, VoIP service users such as dial pads using network address translation technology use external data (when calling outside). In other words, it can transmit its own voice, but it may cause a problem that the external user's data (ie, the external user's voice) is not transmitted because the public IP address and port of the internal user are unknown.

SUMMARY OF THE INVENTION The present invention provides a data communication method of a router for preventing a case in which data cannot be properly received when transmitting and receiving multimedia data including voice in an internet network including a router to which a network address translation technology is applied. To provide.

Another technical problem to be solved by the present invention is to receive data from a counterpart when a user transmits and receives multimedia data in an internet network including a router, a VoIP server, and a gateway for connecting to another communication network. The present invention provides a method and system for communicating data to prevent a case where it cannot be done.

1 is a flowchart illustrating a flow of a communication method of a router to which a network address translation technology is applied.

2 is a data communication system on the Internet including a router to which a network address translation technology is applied.

3 is a flowchart illustrating a flow in which a user connected to a router to which a network address translation technology is applied exchanges data with a user connected to another communication network.

4 illustrates an example of a database storing information related to an IP address and a port of a user stored in a router and a server.

5 is a diagram illustrating a configuration of an identification packet that a user transmits to a server.

In order to achieve the above object, a communication method of a router according to the present invention comprises the steps of: allocating a private IP address and a port to a user computer requesting Internet access among the user computers; Converting the private IP address and port of the user into a public IP address and port; Storing the unauthorized IP address and port and corresponding public IP address and port, respectively; Transmitting an identification packet including the unauthorized IP address and port and a user ID, and the public IP address and port to a server; And transmitting to the user computer data transmitted by a server that recognizes an unauthorized IP address and port of the user and a corresponding public IP address and port, respectively, according to the identification packet and the public IP address and port. It features.

According to another aspect of the present invention, there is provided a data communication method on the Internet, in which a call is established between the user and a server connected to the communication network according to a user's request; Mapping a private IP address and a port of the user to a public IP address and a port to form and store a first mapping table; Transmitting, by the user, an identification packet including the private IP address and port and a user ID, and the public IP address and port to the server; The server configuring and storing information about the user as a second mapping table based on the received identification packet and the public IP address and port; And transmitting, by the server, data from another user to which the user wants to communicate based on a second mapping table.

In order to achieve the above object, a data communication system on the Internet includes: a router for allocating and storing a public IP address and port for an unauthorized IP address and port of the user computer when an Internet connection request is made from the user computer; A plurality of user computers connected to the router for making a connection request and sending an identification packet including its ID, private IP address and port to a server connected via the Internet; A server for setting up a call according to a request of the user computer, receiving the identification packet, and storing an ID of the user computer, an unauthorized IP address and a port, and a corresponding public IP address and port; And a gateway connected to the Internet and connected to another communication network including a public telephone network to provide a connection between the user computer and a user connected to the other communication network.

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

1 is a flowchart illustrating a flow of a communication method of a router to which a network address translation technique is applied, and FIG. 4 is an example of a database storing information related to an IP address and a port of a user stored in a router and a server. 5 is a diagram illustrating a configuration of an identification packet that a user transmits to a server.

If your computer requests an Internet connection while having a private IP address and port 30, for example 10.33.96.5 (step 101), the router will assign this private IP address and port 30 to, for example, 198.76.29.7. The port is then converted to 35 (step 103). Converting IP addresses and ports in this way allows the user to efficiently utilize resources as many user computers are connected to the router as described above and users do not always connect at the same time if they have limited public IP addresses.

Meanwhile, the router builds a mapping table based on the IP address and port generated when a connection request is made. One example of this mapping table is FIG. As can be seen from Figure 4, this mapping table stores the ID of the user computer connected to the router, an unofficial IP address and port assigned at the time of connection request, and a public IP address and port assigned after conversion, respectively. On the basis of this, data transmission and reception between the user computer and the external access computer is connected.

However, when processing voice or video data such as VoIP server, there may be a problem that the public IP address and port of the user connected to the router may not be known. Therefore, the private IP address and the private IP address assigned to the user are prevented. In-port and user ID are made into an identification packet and sent to the VoIP server along with the public IP address and port (step 107).

The VoIP server receiving the identification packet, the public IP address, and the port can know the exact address and port of the connected user, so that the user can send the desired data without loss (step 109).

Another preferred embodiment of the present invention will be described with reference to the drawings.

2 is a data communication system on the Internet including a router to which a network address translation technology is applied, and FIG. 3 is a flowchart illustrating a flow in which a user connected to a router to which a network address translation technology is applied exchanges data with a user connected to another communication network. .

4 illustrates an example of a database that stores information related to IP addresses and ports of a user stored in a router and a server, and FIG. 5 illustrates a configuration of an identification packet that a user transmits to a server.

First, a case in which a user computer attempts to perform voice communication using VoIP while a plurality of user computers 201 are connected to a router 203 to which a network address translation technology is applied will be described. VoIP is a term that refers to IP telephony technology for a series of facilities that use IP to deliver voice information. The main advantage of VoIP and Internet telephony technology is that telephone users can receive long-distance and international calling services over the Internet or intranet environment by using local IP rates by integrating and implementing telephone service. In addition to the original IP function, VoIP uses the Real Time Transport Protocol (RTP) to support packets arriving in a timely manner, so the problem described above may occur, and thus, the steps described below may be solved.

First, a user computer connects a call to a VoIP server 207 using a TCP / IP protocol through a router 203 that applies network address translation technology to make a call with a telephone 213 connected to a public telephone network (PSTN). It sends a setup message for the user, which includes the user ID and IP address and port information for RTP reception. The VoIP server receiving the setup message sends a message to the user's computer that the call being requested is in progress on the VoIP server. Subsequently, a message is sent back to the user computer indicating that the currently requested call is being delivered to the other party. If the other party accepts the call requested by the user computer after the message is delivered, the call is established by transmitting a connection message including the IP address and port information to which the other party wants to receive RTP to the user computer (step 301).

On the other hand, the user computer transmits the identification packet as shown in FIG. 5 to the VoIP server 207 on the User Datagram Protocol (UDP) after step 301. This identification packet contains information including user ID, unauthorized IP address, and port number. An example of the structure of the identification packet is expressed as Pseud-code as follows.

typedef struct {

unsigned int userid;

u_long hostipaddr;

unsigned short port;

} msgip;

The port information in this identification packet is the port to receive by RTP. For example, this port value is generated evenly in the case of RTP and 1 in the case of RTCP (Real Time Control Protocol). In addition, since internal user computers connected to the router 203 can establish a call at the same time, the port value is uniquely generated to have a fourth value of its private IP address so as not to overlap the ports in this case.

On the other hand, when the above-mentioned identification packet is transmitted, the router 203 constructs a mapping table of a user ID and an unauthorized IP address and port in the packet, and a corresponding public IP address and port in the form as shown in FIG. 4 (205). ). In addition, when receiving the identification packet, the VoIP server stores the mapping table constructed in the router 203 in the same manner, and sets an H.323 call with the gateway 209 to set an unauthorized IP address and port of the user computer obtained through the identification packet. When call setup, call is established. Thus, the VoIP server is a public IP address and port of the user's computer, which is the final destination of voice data transmitted from the telephone 213 connected to the public telephone network (PSTN) 211 connected through the gateway 209, and the corresponding non-approved. Since the IP address and port are known exactly, it can be forwarded without error (step 209).

In addition, steps 201 and 203 are repeated one more time because the port information of the RTCP needs to be transmitted. In addition, unlike TCP, UDP, which is a protocol through which an identification packet is delivered, does not require retransmission and thus may be lost on the network. Therefore, the identification packet is sent three times. The reason for including the user ID in the identification packet is to distinguish the identification packet in the VoIP server when a plurality of user computers 201 simultaneously set up a call. At this time, the user ID initially uses the user ID transmitted when setting up a call between the user computer and the VoIP 207 server.

However, some of the network address translation routers include the IP address of the other party to which the user's computer wants to connect in the mapping table. In this case, after the user's computer completes the call setup with the VoIP, a procedure for sending an identification packet to the gateway 207 is required (step 307). The gateway 207 receiving this identification packet builds a mapping table having the same contents as the mapping table stored in the VoIP server 207.

In the above description, the user computer transmits and receives voice data as an example, but the data communication method on the Internet according to the present invention communicates multimedia data such as video data over UDP through a router to which a network address translation technique is applied. The same applies to the case.

The invention may also be embodied as computer readable code on a computer readable recording medium. Computer-readable recording media include any type of recording device that stores data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, and hard disk. Disks, floppy disks, flash memory, optical data storage, and the like, and those implemented in the form of carrier waves (eg, transmission over the Internet). The computer readable recording medium can also be distributed over computer systems connected over a computer network so that the computer readable code is stored and executed in a distributed fashion.

As described above, it is possible to prevent the phenomenon that the data transmitted from the other party may not be properly transmitted when sending and receiving data using UDP such as voice or video through a router to which network address conversion technology is applied. For example, a limited number of public IP addresses can be used efficiently when multiple users connect.

Claims (7)

In a method in which a router connected to a plurality of user computers communicates with a server connected through a communication network, (a) assigning a non-public IP address and port to the user's computer that requires access to the Internet; (b) converting the user's private IP address and port into a public IP address and port; (c) storing the unauthorized IP address and port and corresponding public IP address and port respectively; (d) transmitting an identification packet including the unauthorized IP address and port and a user ID, and the public IP address and port to a server; And (e) forwarding to the user computer data transmitted by a server recognizing a private IP address and port of the user and corresponding public IP address and port according to the identification packet and the public IP address and port, respectively. A data communication method of a router, characterized in that. A method of communicating by a plurality of user computers accessing a communication network including the Internet by using one or more public IP addresses and ports, (a) establishing a call between the user and a server connected to the communication network at the request of the user; (b) mapping a private IP address and a port of the user to a public IP address and a port to form and store a first mapping table; (c) the user sending an identification packet including the private IP address and port and a user ID, and the public IP address and port to the server; (d) the server configuring and storing information about the user as a second mapping table based on the received identification packet and the public IP address and port; And and (e) the server transmitting data from another user to which the user wishes to communicate based on a second mapping table. The method of claim 2, wherein the step (c) further comprises transmitting the identification packet to a gateway connected to the communication network and to another communication network including a public telephone network to provide an inter-network connection. Data communication method. The method of claim 3, wherein the gateway receives the identification packet and stores the user's ID, private IP address and port, and corresponding public IP address and port number according to the identification packet to route the data transmitted to the user. A communication method on the Internet, which is specified. A router for allocating and storing a public IP address and a port for an unauthorized IP address and port of the user computer when a request for access to the Internet is made from the user computer; A plurality of user computers connected to the router for making a connection request and sending an identification packet including its ID, private IP address and port to a server connected via the Internet; A server for setting up a call according to a request of the user computer, receiving the identification packet, and storing an ID, an unauthorized IP address and a port of the user computer, and a corresponding public IP address and port; And a gateway connected to the Internet and connected to another communication network including a public telephone network to provide a connection between the user computer and a user connected to the other communication network. 7. The data communication of claim 6, wherein the gateway further comprises receiving the identification packet and storing an ID of the user computer, a non-official IP address and port, and a corresponding public IP address and port. system. A method of communicating by a plurality of user computers accessing a communication network including the Internet by using one or more public IP addresses and ports, Setting up a call between the user and a server connected to the communication network according to the user's request; Mapping a private IP address and a port of the user to a public IP address and a port to form and store a first mapping table; Transmitting, by the user, an identification packet including the private IP address and port and a user ID, and the public IP address and port to the server; The server configuring and storing information about the user as a second mapping table based on the received identification packet and the public IP address and port; And A computer-readable recording medium having recorded thereon a program for causing the server to transmit data from another user to which the user wishes to communicate based on a second mapping table.