KR100662941B1 - Method for converting network address on data relay between a public network and a private network - Google Patents

Abstract

The present invention relates to a method of translating a network address when relaying a message to an external wide area network of a device connected to a home network. The present invention relates to a public network using a public IP address and a private IP address. The gateway to the home network using the IP address removes the public IP address header of the message received from the first device connected to the public network, thereby removing the private IP address of the second device and the private IP address of the first device. Step 1 of transmitting an address header composed of a public IP address to the second device through the home network, and replacing the source private IP address in the message received from the second device with its own public IP address. Transmitting to the first device through a second step of mapping and registering the socket information included in the message with the replaced source private IP address; Placed the destination public IP address of the message, substituting the private IP address of the registered socket is mapped to the information of the message, it performs a three-step for transmitting to the home network.

Home network, address, translation, tunneling, socket, port number

Description

How to convert network address during data relay between public and private networks {Method for converting network address on data relay between a public network and a private network}

1 illustrates an example of adding and deleting an IP address header for IP tunneling.

2 illustrates a simplified configuration example of a network to which an embodiment of the present invention is applied and a process of converting a network address according to the present invention.

Explanation of symbols on the main parts of the drawings

1,100: IGD 2,200: PDA

3: stove

The present invention relates to an address tunneling method for converting a public network address or a private network address of data into a private network address or a public network address during data relay between a public network and a private network such as a home network.

With the spread of various video devices, audio devices, and electronic devices such as PCs, and digital and transmitted video and audio signals in one home, communication between electronic devices and communication with external networks are increasing. In addition, due to the presence of a large number of electronic devices in a home, there is an increasing desire to concentrate the control on the operation of a single device, for example, a mobile device such as a PDA.

In order to meet such needs, home networking, which connects home appliances such as DVD players, digital televisions, and the like, is emerging. UPnP (Universal Plug and Play) technology has been proposed as one of such home networking.

According to the UPnP standard, home networking requires a device that assigns / distributes addresses to elements (or nodes) that are connected to the network, which is an external wide area network, such as the Internet. It is assigned a public IP address, that is, a gateway to the public network, so that the devices connected to the home network can communicate with the external wide area network, that is, the Internet. The device is called IGD (Internet GateWay Device), which can be implemented as a standalone device or integrated into a PC or refrigerator.

In order to efficiently use limited public address resources, each device connected to the home network is assigned with a private IP address that is randomly assigned to the home network instead of individually assigned public IP addresses. Done.

By the way, a user who has built a home network in the home may need to remotely inquire or control the status of the home device remotely, instead of inquiring or controlling each device using a device connected to the home network. . In such a case, a terminal assigned a public IP address must be used to communicate with an arbitrary device that has been assigned a private IP address in its own home network through the Internet. You need to convert your private IP address. This is called IP tunneling.

Figure 1 shows an example of this, a device that is assigned a public IP address from the public network, for example, the device assigned to the private IP address connected to the PAD (2) and the home network (HN), for example a gas stove In the message exchange between (3), it shows the address translation process performed in the IGD (1) to which a public IP address is assigned. In FIG. 1, name domains (private.gasrange, public.IGD, etc.) are used instead of the actual IP addresses for convenience of description, but these names are the same as the addresses because they all correspond one-to-one with IP addresses, and private.xxx is private. The IP address public.xxx represents the public IP address.

First, when the message is transmitted from the PDA 2 to the stove 3, the PDA 2 is a destination / source address of the data 11c to be transmitted to the stove 3 (hereinafter, After setting 'Dest / Src' as private.gasrange / public.PDA (11b), the private.gasrange of the destination is not the address specified by the stove 3 in the public network, so that the IP for the public network The message 11 is constructed by adding an address header 11a, Dest / Src = public.IGD / public.PDA to the front end. This is to transfer the data 11c to the stove 3 to the IGD 1 of the home network HN.

The message 11 configured as described above is transmitted to the IGD 1 via a public network, and the IGD 1 removes the IP address header 11a at the front end of the message 11 to the home network HN. The sub address header 11b, which can specify the exact destination at, is positioned at the leading end of the message and transmitted to the home network HN to reach the gas stove 3.

In response to the message, when the gas stove 3 transmits the data 12b to the PDA 2, the source address in the received message, namely public.PDA, is the destination and its own private IP address is sent. The message 12 is constructed by adding a header 12a serving as an address. When the message 12 thus constructed is transmitted to the home network HN, it is received by the IGD 1 since the public IP address is the destination. Then, the IGD 1 constructs a new IP address header 13 and adds it to the front end of the received message 12 because the source address is not a public IP address. The destination address of the received message 12 is copied to the destination address of the new IP address header 13 and its public IP address, namely public.IGD, is recorded in the source address. The message 12 + 13 configured as described above arrives at the PDA 2 via the public network, thereby transferring the data 12b transmitted by the gas stove 3 to the PDA 2.

However, the IGD 1 performs the operation of adding or deleting the above-described IP address header at every message exchange between the PDA 2 and the stove 3. However, this operation involves overhead such as memory allocation and deallocation, which is a delay factor in message transmission, and if the data exchange with the public network is very frequent, the performance for communication in the IGD's home network ( performance may be reduced.

Accordingly, the present invention has been made to solve the above problems, and it is possible for a gateway device of a local network such as a home network to add and delete an address header when relaying a message with an external wide area network of a device connected to the local network. Its purpose is to provide a method of translating network addresses that is not needed.

In order to achieve the above object, according to the present invention, a gateway device between a public network using a public address and a local network using a private address may include a public address header of a message received from a first device connected to the public network. Removing a to have an address header including a private address of a lower second device and a public address of the first device, and transmitting the same to the second device through the local network; The source private address in the message received from the second device is replaced with its own public address and transmitted to the first device through the public network, and the socket information included in the message and the replaced source private address are transmitted. Two steps of mapping and registering; And performing a third step of replacing the destination public address of the message received from the first device with a private address registered and mapped to the socket information of the message, and sending it to the local network.

Further, according to the present invention, a first device connected to a public network using a public address establishes a socket for communication with a second device connected to a local network using a private address and establishes a socket information. Registering and mapping a source port address with a private address of the second device; A first address header comprising a private address of the second device and its own public address is added to the data to be transmitted, and a second address header composed of the public address of the gateway device for the local network and its own public address is placed on top of the data. Additionally constructing a message; Transmitting the socket information to the public network by including the socket information in the configured message; And if the source address of the message received through the public network is the address of the gateway device, and if the destination port number in the socket information of the message is the same as the registered source port number, the source of the received message is the second. It is characterized by performing four steps of determining that the device.

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

FIG. 2 illustrates a simplified configuration example of a network to which an embodiment of the present invention is applied and a process of translating a network address according to the present invention. The exchange of messages is performed by a device connected to a public network, for example, a PDA 200 and a home. The process of translating the network address when the device connected to the network HN, for example, the stove 3, is performed is shown. First, when the message is first transmitted from the PDA 200 to the gas stove 3, the PDA 200 is the destination / destination address of the data (11c) to be transmitted to the gas range (3) , Designated as 'Dest / Src') as private.gasrange / public.PDA (11b), and since the destination's private.gasrange is not the address specified by the gas range (3) in the public network, The message 11 is constructed by adding the IP address header 11a, Dest / Src = public.IGD / public.PDA to the front end. This is to transfer the data 11c to the gas range 3 to the IGD 1 once. The message 11 configured as described above is transmitted to the IGD 100 via a public network, and the IGD 100 removes the IP address header 11a at the front end of the message 11, thereby providing a home network (HN). A sub-address header 11b in which a destination can be uniquely identified is positioned at the front of the message to be sent to the home network HN to reach the gas stove 3. This process is the same as the conventional process described above with reference to FIG.

However, the PDA 200 establishes a socket before transmitting a message as described above. At this time, information about a protocol, a destination port number, and an IP address in its communication module is established. The communication module allocates a source port number to a combination of the provided information and its own IP address, and establishes a socket. If the provided IP address is a private IP address, IP tunneling is performed. As determined to be necessary, the public IP address of the IGD 100 of the preset home network HN is added to the socket information. One unique socket is determined by the protocol, destination port number and IP address, source port number and IP address, and the public IP address of the device (IGD) where IP tunneling takes place. At this time, the information that maps the assigned source port number and the destination IP address, for example, private.gasrange is registered.

The destination port number and the IP address may be known through a URL described in a device description of a corresponding device which has been previously received and stored, for example, a URL for presentation. The information is inserted in the header of each packet to be transmitted and received and transmitted to the other side.

On the other hand, when the stove 3 transmits the data 12b to the PDA 2 in response to the received message 11b + 11c, the source address in the received message, namely public.PDA, is destined for the destination. Then, a message 12 is constructed by adding a header 12a whose own address is the source address. When the message 12 configured as described above is transmitted to the home network HN, the IGD 1 serving as a gateway function because the public.PDA is out of the range of the private IP address assignable to the home network HN. Is received. Of course, in the header of the packet for transmitting the message 12, the information of the open socket in the PDA 200 is loaded according to the destination and the source.

Since the source address is not a public IP address, the IGD 100 replaces it with a public IP address 12a '. At this time, the socket information in the header of the packet is used and the conversion information is also written (S21). ). In other words, in the address translation table managed by the user, an entry in which the socket address of the packet whose IP address is translated from private to the public and the translated private IP address, namely, private.gasrange, is created and written in one-to-one mapping. . This process is performed by a network address translation (NAT) module in the IGD 100.

As described above, the message 120 having the header 12a 'whose IP address is changed arrives at the PDA 200 via a public network. The PDA 2 then finds the source of the message 120 from the socket information in the header of the packet. That is, the destination IP address mapped to the destination port number (the source port number given when the PDA 200 itself opens a socket) registered as mapping information, that is, private.gasrange, Src = public It will determine the source of the message received in .IGD.

After receiving the response message 120 as described above, the PDA 200 sends an IP address header for the public network, that is, Dest / Src = public when the message is sent to the source of the message, that is, the stove 3. Instead of adding .IGD / public.PDA to the front end, only the message 121 destined for the IGD 100 is constructed and transmitted. Then, the message 121 is delivered to the IGD 100 through a public network, and the NAT module performs a mapping entry in which a mapping entry having the same socket information as the socket information in the header of the packet carrying the message is previously created. If it finds and replaces the current destination address (public.IGD) with the private IP address in the entry, that is, private.gasrange and sends it to the home network (HN) (S22), the message 121 'indicates that the gas stove 3 Delivered to.

As mentioned above, preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and those skilled in the art can improve other various embodiments within the spirit and technical scope of the present invention disclosed in the appended claims below. Changes, substitutions or additions will be possible.

According to the present invention described in detail above, when a user remotely performs inquiry and / or control of a device connected to a home network from outside of the home network, the gateway of the home network may perform an operation of adding or deleting an IP address header. There is no need to do this, which reduces the load on the system and speeds up message delivery.

Claims (7)

A method of translating a network address during communication between a first device connected to a public network using a public address and a second device connected to a local network using a private address, the method comprising: Remove the public address header of the message received from the first device to have an address header consisting of the private address of the second device below and the public address of the first device to the second device through the local network. Transmitting step 1; The source private address in the message received from the second device is replaced with the public address of the gateway device and transmitted to the first device through the public network, the socket information contained in the message and the replaced source private address. Step 2 to register by mapping; And And replacing the destination public address of the message received from the first device with a private address registered and mapped to the socket information of the message, and sending it to the local network. The method of claim 1, The socket information is information specified when the first device establishes to send a message to the second device. The method of claim 2, And said socket information comprises a protocol, source port number and address, destination port number and address, and address of said gateway device. A method for adding a network address when a first device connected to a public network using a public address communicates with a second device connected to a local network using a private address, Opening a socket for communication with the second device and registering and registering a source port address of the opened socket information and a private address of the second device; A first address header comprising a private address of the second device and its own public address is added to the data to be transmitted, and a second address header composed of the public address of the gateway device for the local network and its own public address is placed on top of the data. Additionally constructing a message; Transmitting the socket information to the public network by including the socket information in the configured message; And If the source address of the message received through the public network is the address of the gateway device, and if the destination port number in the socket information of the message is the same as the registered source port number, the source of the received message is the second device. And comprising four steps of determining to be: The method of claim 4, wherein In addition, an address header including a destination address of a message received in step 4 as a source address and a source address as a destination address is added to data to be transmitted to the second device, and configured as a message to include the opened socket information. The method further comprises the step of transmitting to the public network. The method of claim 4, wherein And when the message is sent to the second device after step 4, the first address header is not added. The method of claim 4, wherein And said socket information comprises a protocol, source port number and address, destination port number and address, and address of said gateway device.

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