Apparatus for converting internet protocol address and home network system using the same

An internet protocol address converting apparatus has an address acquiring unit for acquiring a first private IP address in a first IP address format by connecting to a DHCP server that dynamically allots the IP address, and also acquiring a second private IP address for the second terminal; a network address providing unit for allotting the second terminal with a network address to generate a global IP address; a storing unit for storing a mapping table, the mapping table saving the second private IP address of the second terminal and the global IP address; an address converting unit for converting the second private IP address into the global IP address; and a control unit for performing an announcing, requesting a registration of the second terminal to a master server.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an apparatus for converting an Internet protocol address for exclusive use in a home network system and a home network system using the same, and more particularly, the present invention relates to an apparatus for converting an Internet protocol address for exclusive use in a home network that is capable of providing a service for achieving a communication between an IPv4 terminal using an Internet Protocol version 4 (IPv4) as a communication protocol and an IPv6 terminal using Internet Protocol version 6 (IPv6) as a communication protocol, and a home network system using the same. This application claims priority from Korean Patent Application No. 2002-0005227, filed on Jan. 29, 2002, which Korean Application is incorporated herein in full by reference.

2. Description of the Prior Art

Internet Protocol (IP) is one of the most generally known protocols used for the network layer of TCP/IP communication. The IP is the addressing service provided by a network layer of third layer of Open Systems Interconnection model, which designates a plurality of nodes connected to the network as a destination to perform communication. Among the IPs that are currently available, the most popular one is the Internet Protocol version 4 (IPv4). The IPv4 uses an IP address of 32 bits.

With the ever-growing number of users, computers are now becoming a necessity in people's daily lives. The number of addresses of Internet users has been exploding, while the IPv4 IP address format of 32 bits hardly satisfies such continuously growing demands. In an attempt to solve this problem, IPv6 has been developed by the Internet Engineering Task Force (IETF) as the next generation Internet Protocol.

The IPv6 uses the address format of 128 bits. The IPv6 not only extends the number of IP addresses, but also reduces costs for broadband width and processing of a common header, as it is capable of simplifying the common header format. Also, by adopting a concept of ‘flow label,’ IPv6 enables efficient real-time processing of multimedia data. Moreover, the IPv6 provides much strengthened security functions like verification, faultless data, airtight data, etc.

The Internet communication infrastructure used for the IPv4 is also used for the IPv6. Accordingly, in order to accomplish a communication between the IPv4 terminal and the IPv6 terminal, an IPv4-IPv6 converter that connects the IPv4 net and the IPv6 net is necessary.

FIG. 1is a block diagram showing network system using a conventional IPv4-IPv6 converter. Referring toFIG. 1, conventionally, the IPv4 network20and the IPv6 network40are connected by the IPv4-IPv6 converting device10. The IPv4 network20is connected with an IPv4 terminal31, a domain name service version 4 server (DNSv4) 33, and a dynamic host configuration protocol version 4 server35(DHCPv4). The DNSv4 server33manages the domain name information within the IPv4 network20. The DHCPv4 server35dynamically allots the IPv4 address to the IPv4 terminal31that is connected to the IPv4 network20.

The IPv6 network40is connected to an IPv6 terminal51, a DNSv6 server53and a DHCPv6 server55. The DNSv6 server53manages the domain name information within the IPv6 network40. The DHCPv6 server55dynamically allots the IPv6 address to the IPv6 terminal51that is connected to the IPv6 network40.

The communication operation between the IPv4 terminal31and the IPv6 terminal51will be described below.

First, the IPv4 terminal31makes a query to the DNSv4 server33for an IPv4 address that corresponds to the domain name of the IPv6 terminal51. The DNSv4 server33provides the IPv4-IPv6 converting device10with the information about the requested IPv4 address that corresponds to the domain name of the IPv6 terminal51. The sender address is the IPv4 address of the DNSv4 server33, while the destination address is the IPv4 address of the IPv4-IPv6 converting device10. The IPv4-IPv6 converting device10converts the IPv4 address of the sender, i.e., of the DNSv4 server33into the IPv6 address. At this time, the IPv4-IPv6 converting device10converts the IPv4 address of the DNSv4 server33into the IPv6 address by adding a prefix to the IPv4 address of the DNSv4 server33. The IPv4-IPv6 converting device10also has the IPv6 address of the DNSv6 server53that manages the domain information of the terminal like the IPv6 terminal51that is connected to the IPv6 network40. Accordingly, the IPv4-IPv6 converting device10is connected to the DNSv6 server53and requests the IPv6 address corresponding to the domain name of the IPv6 terminal51. The sender address is the IPv6 address of the DNSv4 server33, while the destination address is the IPv6 address of the DNSv6 server53.

The IPv6 address corresponding to the domain name of the IPv6 terminal51being requested, the DNSv6 server53extracts the IPv6 address from a stored table and provides the IPv4-IPv6 converting device10with the extracted information. The IPv4-IPv6 converting device10converts such received IPv6 address of the IPv6 terminal51into the IPv4 address, and provides the DNSv4 server33with such converted IPv4 address of the IPv6 terminal51. The DNSv4 server33provides the IPv4 terminal31with such received IPv4 address of the IPv6 terminal51. Accordingly, the IPv4 terminal31is enabled to find out the IPv4 address that corresponds to the domain name of the IPv6 terminal51.

Provided with the IPv4 address corresponding to the domain name of the IPv6 terminal51, the IPv4 terminal31sends a communication request signal with the IPv6 terminal51to the IPv4-IPv6 converting device10. The sender address is the IPv4 address of the IPv4 terminal31, while the destination address is the IPv4 address of the IPv6 terminal51. When the IPv4 terminal sends the control information to the terminal in the IPv6 network40, a mapping table within the converting device10is searched. If there is an IPv6 terminal51registered for the IPv4 address, i.e., the destination address, there is no need to perform the converting process additionally. With the address of IPv6 system with respect to the IPv4 terminal31and the IPv6 terminal51, the IPv4-IPv6 converting device10sends a connection request signal from the IPv4 terminal31to the IPv6 terminal51. With the address conversion by the IPv4-IPv6 converting device10, the IPv4 terminal31and the IPv6 terminal51communicates with each other.

FIG. 2is a view showing one example in which the network system using the IPv4-IPv6 converting device10ofFIG. 10is used in the home network system. The IPv4-IPv6 converting device10as used in the home network is called a home-only IP address converting device. However, it will be understood by those of ordinary skill in the art that the devices, systems and methods disclosed herein are not restricted to use In a home. Rather, what is intended is any application, including an office, vehicle, school, or other such environment, for which the devices, systems and method herein disclosed are suitable.

Hereinbelow, the communication operation between the IPv4 terminal31, namely, a personal computer31aand a refrigerator31band the IPv6 terminal51, namely, a digital television51aand a laptop computer51b.

Based on the services provided by the DNSv4 server33and the DHCPv4 server35, the personal computer31aand the refrigerator31bperform a communication with the devices within the IPv4 network20a. Also, based on the services provided by the DNSv6 server53and the DHCPv6 server55, the digital television51aand the laptop computer51bperform the communication with the devices within the IPv6 network40a.

Meanwhile, in order to achieve a home networking among the communicable devices within the home network, the home network system is provided with a master server37. The master server37manages and registers the registration information of the devices of the home network. The registration information may not necessary include additional information about IP address, as it will become known through a FPC communication.

The conventional home network system requires the IPv4-IPv6 converting device10that provides a converting service of converting the IP address formats for a communication between the IPv4 terminal31and the IPv6 terminal51. By the services provided by the IPv4-IPv6 converting device10, communication among the personal computer31aand the refrigerator31b, and the digital television51aand the laptop computer51bis enabled. In order to apply the IPv4 terminal31and the IPv6 terminal51in the home network system, the home network requires the DNSv4 server35and the DHCPv4 server35that provide the IPv4 terminal of the home network with the IP address and the domain name, and also the DNSv6 server53and the DHCPv6 server55that provide the IPv6 terminal of the home network with the EP address and the domain name, which generates inconvenient jobs such as system establishment, etc.

There is another problem that the services of the DNSv6 server53and the DHCPv6 server55become redundant with respect to the services of the DNSv4 server33and the DHCPv4 server35. Also, in order for the IPv4 terminal31and the IPv6 terminal51to communication with each other, the IPv4 terminal31and the IPv6 terminal51have to use the services of the DNSv4 server33and the DHCPv4 server35and the DNSv6 server53and the DHCPv6 server55. Accordingly, communication among the IPv4 terminal31and the IPv6 terminal51sometimes causes overload in the operation of the respective servers33,35,53,55.

Also, since the conventional home network requires the installation of all of the DNSv4 server33, the DHCPv4 server35, the DNSv6 server53and the DHCPv6 server55therein, a problem of taking too much space arises.

SUMMARY OF THE INVENTION

The present invention has been made to overcome the above-mentioned problems of the prior art. Accordingly, it is a first object of the present invention to provide an IPv4-IPv6 converting device that solves the problem of the high costs for building a home network that requires a DNSv4 server33, a DHCPv4 server35, a DNSv6 server53and a DHCPv6 server55for a communication among an IPv4 terminal and an IPv6 terminal within a home network.

It is a second object of the present invention to provide an IPv4-IPv6 converting device that solves the problem of transmission overload between an IPv4 terminal and an IPv6 terminal.

It is a third object of the present invention to provide an IPv4-IPv6 converting device that reduces a space occupied by a DNSv4 server, a DHCPv4 server, a DNSv6 server and a DHCPv6 server during the establishment of home network for communication between an IPv4 terminal and an IPv6 terminal.

In order to accomplish the above objects, an apparatus for converting an IP address format for a communication between a first terminal and a second terminal having different IP address formats according to the present invention includes an address acquiring unit for acquiring a first private IP address in a first IP address format by connecting to a DHCP server that dynamically allots the IP address, and also acquiring a second private IP address for the second terminal; a network address providing unit for allotting the second terminal with a network address according to a network address request by the second terminal to generate a global IP address of a second IP address format; an address converting unit for converting the second private IP address into the global IP address; a storing unit for storing a mapping table, the mapping table saving the second private IP address of the second terminal and the global IP address; and a control unit for performing an announcing, requesting a registration of the second terminal to a master server that manages and provides registration information about the second terminal having the global IP address.

The control unit controls the address converting unit so that the second private IP address is converted into the global IP address according to the mapping table, when received with the control signal with respect to the second terminal having the second private IP address. The control unit controls the address converting unit so that the global IP address is converted into the second private IP address according to the mapping table, when being requested by the second terminal having the global IP address to register the information about the second terminal in the master server. The first IP address format is an IPv4, and the second IP address format is an IPv6.

The second terminal combines the network address provided by the network address providing unit with a hardware address of the second terminal, to generate the global IP address. The hardware address is a media access control address, which is an interface ID distinguishing one interface from another connected in a network. Each of the media access control address and the network address is comprised of 64 bits.

Also in order to accomplish the above objects, a home network system according to the present invention includes an IPv4 terminal for performing a communication with a device connected to an IPv4 network with a hardware address and a private IPv4 address in an IPv4 system; an IPv6 terminal for performing a communication with a device connected to the IPv6 network with the hardware address and a global IPv6 address in the IPv6 system; an address converting device for performing a communication with the IPv4 terminal in the IPv4 network with the private IPv4 address, and providing the IPv6 terminal with a network address so that the IPv6 terminal can generate the global IPv6 address; a DHCP server for allotting the IPv4 terminal, the IPv6 terminal and the address converting device with the private IPv4 address in the IPv4 system; and a master server for managing and providing registration information about the IPv4 terminal and the IPv6 terminal.

The address converting device includes a mapping table saving the private IPv4 address of the IPv6 terminal and the global IPv6 address. The registration information comprises the hardware address of the IPv4 terminal and the IPv6 terminal, the private IPv4 address and the global IPv6 address.

The address converting device converts the private IPv4 address into the global IPv6 address according to the mapping table, when being received with the control signal for the IPv6 terminal having the private IPv4 address. The address converting device converts the global IPv6 address into the private IPv4 address according to the mapping table, when being requested by the IPv6 terminal having the global IPv6 address to perform an announcing for registering the information about the IPv6 terminal in the master server.

The IPv6 terminal generates the global IPv6 address by combining the network address provided by the address converting device with the hardware address of the IPv6 terminal. The hardware address is a media access control address, an interface ID distinguishing one interface from another which are connected in a network. Each of the media access control address and the network address is comprised of 64 bits.

Also in order to accomplish the above objects, a communication method using an address converting apparatus which converts an IP address format to enable a communication between a first terminal and a second terminal having different IP address formats according to the present invention includes the steps in which: the first terminal is connected to a DHCP server that allots a private IP address in a first IP address format, and acquires a first private IP address in the first IP address format of the first terminal; the apparatus for converting the address is connected to the DHCP server, and acquires a second private IP address thereof; the second terminal is connected to the apparatus for converting the address and generates a global IP address in a second IP address format through a network address provided by the apparatus for converting the address; the apparatus for converting the address is connected to the DHCP server and acquires a first private IP address in the first IP address format corresponding to the global IP address of the second terminal; a mapping table saving the global IP address and the first private IP address of the second terminal is stored in a storing unit of the apparatus for converting the address; and the information about the first and the second terminals are managed and provided.

The address generating step generates the global IP address by combining the network address provided by the apparatus for converting the address with the hardware address of the second terminal. The hardware address is a media access control address, an interface ID distinguishing one interface from another which are connected in the network. Each of the network address and the media access control address is comprised of 64 bits.

In one embodiment, the first IP address format is an IPv4, and the second IP address format is an IPv6. However, it will be understood that the devices, systems and methods disclosed herein are suitable also for other IP protocol conversion applications.

According to the present invention, the IPv6 address is generated through the network address provided by the network address providing unit130, and the DHCPv4 server350allots the IPv4 address corresponding to the IPv6 address of the IPv6 terminal510, and the IPv4 address and the IPv6 address of the IPv4 terminal310and the IPv6 terminal510are stored in the mapping table of the storing unit140, and the master server330manages and provides the registration information about the IPv4 terminal310and the IPv6 terminal510. As a result, there is no need to employ the DHCPv6 server and the DNSv6 server for communication.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described in greater detail by referring to the appended drawings.

FIG. 3is a block diagram showing a home-only IP address converting device according to the present invention. Referring toFIG. 3, the home-only IP address converting device includes an address acquiring unit120, a network address providing unit130, a storing unit140, an address converting unit150and a control unit110.

The address acquiring unit120is connected to a DHCPv4 server (not shown) that dynamically allots IP addresses to the devices in the network and acquires a first private IPv4 address and a second private IPv4 address of IPv4 system. The first private IPv4 address is for the home-only IP address converting device to communicate with the devices connected to an IPv4 home network200. The second private IPv4 address corresponds to the IPv4 address of IPv4 system of an IPv6 terminal (not shown) that is connected in an IPv6 home network400.

The network address providing unit130provides an IPv6 terminal requesting a network address by automatically generating an IPv6 address of IPv6 system. Generally, a network address is comprised of 64 bits. Accordingly, the IPv6 terminal has a media access control address (MAC address), which is an interface ID that distinguishes interfaces connected in the network one from another. Such MAC address is comprised of 64 bits. The network address provided to the IPv6 terminal is comprised of 64 bits. Accordingly, the IPv6 terminal adds the network address to its MAC address, and thereby, automatically generates the IPv6 address of the IPv6 system. The IPv6 address of the IPv6 system that is automatically generated by the IPv6 terminal is comprised of 128 bits. The IPv6 address automatically generated for the IPv6 terminal is transmitted by the IPv6 terminal to the control unit110via the IPv6 home network400and the interface unit160.

The storing unit140stores the first private IPv4 address of the IPv4 terminal and the second private IPv4 address of IPv6 terminal, both acquired by the address acquiring unit120, and also stores the IPv6 address of the IPv6 terminal provided by the IPv6 terminal in a mapping table that is constructed under the control of the control unit110. The address converting unit150converts the second private IPv4 address to the IPv6 address or vice versa based on the mapping table stored in the storing unit160. Preferably, the address converting unit150generates the IPv6 address of the IPv6 system that corresponds to the IPv4 address of the IPv4 terminal. As a result, the IPv6 terminal can identify the address of the IPv4 terminal that transmits the control signal.

When the request signal for connection with the IPv6 terminal is received from the IPv4 terminal having the first private IPv4 address via the interface unit160, the control unit110extracts the mapping table stored in the storing unit160and provides the address converting unit150with such extracted mapping table, to thereby control the address converting unit150to convert the second private IPv4 address into the IPv6 address based on the mapping table.

As the network address providing unit130provides the IPv6 terminal with the network address and the IPv6 terminal generates the IPv6 address through the provided network address, there is no need for the DHCPv6 server for providing the IPv6 terminal with the IPv6 address of the IPv6 system.

FIG. 4is a block diagram showing the address acquiring unit120ofFIG. 3in greater detail. The address acquiring unit120has a first address acquiring unit122and a second address acquiring unit124. The first address acquiring unit122is connected to the DHCPv4 server so as for the home-only IP address converting device to communicate within the IPv4 home network200, and acquires the first private IPv4 address of the IPv4 system. The second address acquiring unit124is connected to the DHCPv4 server and acquires the private IPv4 address of the IPv4 system of the IPv6 terminal, which is required for the IPv4 terminal to transmit the control signal to the IPv6 terminal.

FIG. 5is a block diagram showing a home network system employing the home-only EP address converting device ofFIG. 3. The home-only IP address converting device100connects the IPv4 home network200that is connected with the IPv4 terminal310with the IPv6 home network400that is connected with the IPv6 terminal510. Referring toFIG. 5, the IPv4 home network200is connected with the master server330and the DHCPv4 server350. Here, the master server330can be connected with the IPv6 home network400.

Generally, the master server330manages and provides the registration information of the devices in the home network. The master server330according to the present invention stores a domain name of the IPv4 terminal310and the information about the IPv4 terminal310that contains the address corresponding to the domain name. Also, the master server330stores the information about the IPv6 terminal510.

Generally, in order to provide communication service between the IPv4 terminal310and the IPv6 terminal510, all the devices for performing communication among the devices having different address formats are implemented with a middleware. The middleware is the software that provides service for communication among different type of terminals, which enables the communication among a plurality of terminals within the home network. In other words, the middleware functions to independently connect to the hardware along the network so as to support with various communication protocol, system structure, management system, database and application program. Among the currently available middlewares, there are Universal Plug and Play (UPnP), Home AV Interoperability (HAVi), JINI, Home Wide Web.

The DHCPv4 server350dynamically allots addresses according to the address allotment request of the IPv4 terminal310. Also, the DHCPv4 server350provides the first address acquiring unit122with the first private IPv4 address according to the request for an address in IPv4 system with respect to the home-only IP address converting device100of the first address acquiring unit122. The DHCPv4 server350provides the second address acquiring unit124with the second private IPv4 address according to a request for an address in IPv4 system with respect to the IPv6 terminal510of the second address acquiring unit124.

FIG. 6is a view showing the devices within the house used with the home network system ofFIG. 5. Referring toFIG. 6, a personal computer310aas the IPv4 terminal310is arranged within the IPv4 home network200a, while a digital television510aas the IPv6 terminal510is arranged in the IPv6 home network400a. The DHCPv4 server350is additionally arranged in the house to allot the media access control address for the personal computer310ato communicate with other devices in the IPv4 home network200a.

Meanwhile, the personal computer310arequests the master server330for the announcement in order to register the information of the personal computer310acontaining the media access control address of the personal computer310a. The information of the requesting personal computer310aincludes the media access address, a user name and available services of the personal computer310a. Accordingly, the master server330stores the information of the announcement-requested personal computer310ain the table format. The digital television510arequests the home-only IP address converting device100for a network address in order to generate the IPv6 address in IPv6 system. Here, in the case that the master server330is provided within the IPv6 home network400a, the personal computer310atransmits the announcement to the home-only IP address converting device100in order to register the information of the personal computer310ain the master server330. In such a situation, the control unit110in the home-only IP address converting device100requests the master server330for the announcement. Accordingly, the master server330stores the information of the personal computer310ain the table format. The master server330can be provided either in the IPv4 home network200aor in the IPv6 home network400a. In this embodiment, the master server330is depicted as being provided in the IPv4 home network200a.

Also, the digital television510agenerates the IPv6 address in the IPv6 system by combining the network address provided by the home-only IP address converting device100and its own media access control address. Accordingly, the digital television510atransmits the announcement to the home-only IP address converting device100to register in the master server330the information about the digital television510ainclusive of the generated IPv6 address. At this time, the second address acquiring unit124is connected to the DHCP server350and acquires the second private IPv4 address corresponding to the IPv6 address of the digital television510a. Accordingly, the control unit110requests the master server330for the announcement to register the information about the digital television510ahaving the second private IPv4 address in the master server330.

Accordingly, in order to control the operation of the digital television510a, the personal computer310arequests the master server330for the information of the digital television510athat is registered through the announcement. The master server330provides the personal computer310awith the information of the registered digital television510a. Accordingly, the personal computer310aselects a control signal from the provided information about the requested digital television510a, and transmits the selected signal to the home-only IP address converting device100. The address of the digital television510a, which is transmitted to the home-only IP address converting device100, is the second private IPv4 address. The control unit110of the home-only IP address converting device100provides the address converting unit150with the mapping table stored in the storing unit140. Accordingly, the address converting unit150detects the registered IPv6 address that corresponds to the second private IPv4 address of the digital television510a. the recipient of the control signal, and transmits the control signal to the digital television510acorresponding to the detected IPv6 address.

FIG. 7is a flowchart for explaining the announcing of the IPv4 terminal310in the home network system using the home-only IP address converting device100according to the present invention. First, the IPv4 terminal310requests the DHCPv4 server350for a private IPv4 address in IPv4 system (step S110). The DHCPv4 server350allots the IPv4 terminal310with the private IPv4 address (step S120). Accordingly, the IPv4 terminal310requests the master server330to announce in order to register the information about the IPv4 terminal310(step S150). At this time, the master server330registers the received information about the IPv4 terminal310, and transmits to the IPv4 terminal310the information as to whether the information about the IPv4 terminal310is registered or not (step S160).

In addition, the home-only IP address converting device100is connected to the DHCPv4 server350and requests the DHCPv4 server350for an IPv4 address in the IPv4 system to perform communication with the devices existing in the IPv4 home network200a(step S130). Accordingly, the DHCPv4 server350allots to the home-only IP address converting device100the private IPv4 address (step S140).

FIG. 8is a flowchart for explaining the announcing of the IPv6 terminal510in the home network system using the home-only IP address converting device100according to the present invention. First, as the power is supplied, the IPv6 terminal510requests the home-only IP address converting device100for the network address (step S210). The network address providing unit130provides the IPv6 terminal510with a network address (step S220). Accordingly, the IPv6 terminal510generates the IPv6 address in IPv6 system by combining its media access control address and the received network address. At this time, the IPv6 terminal510performs the announcing to the home-only IP address converting device100to register the information about the IPv6 terminal510in the master server330(step S230).

The registration information being requested by the IPv6 terminal510, the second address acquiring unit124of the home-only IP address converting device100is connected to the DHCPv4 server350and requests the DHCPv4 server350for the IPv4 address of the IPv6 terminal510in IPv4 system (step S250). The DHCPv4 server350provides the home-only IP address converting device100with the second private IPv4 address for the IPv6 terminal510(step S260). Accordingly, the home-only IP address converting device100requests the master server330to register the IPv6 terminal510with the allotted second private IPv4 address of the IPv6 terminal510(step S270). The master server330registers the IPv6 terminal510, and provides the home-only IP address converting device100with the registration result (step S280). Receiving the registration result, the home-only IP address converting device100transmits the received registration information to the IPv6 terminal510(step S290).

FIG. 9is a flowchart showing in detail the operation of the home-only IP address converting device100according to the registration requesting step (S230) by the IPv6 terminal510ofFIG. 8to the master server330. First, when the announcing is received from the IPv6 terminal510for registering the information of the IPv6 terminal510in the master server330, the control unit110searches the mapping table of the storing unit140(step S241). Accordingly, the control unit110determines whether or not to register the IPv4 address corresponding to the IPv6 address of the IPv6 terminal510through the mapping table (step S243). The IPv4 address that corresponds to the IPv6 address of the IPv6 terminal510is the second IPv4 address. In other words, the control unit110determines whether or not to register the second private IPv4 address corresponding to the IPv6 address.

When it is determined that the second private IPv4 address is registered in S243, the control unit110requests the master server330through the interface unit160for a registration of the IPv6 terminal510that has the second private IPv4 address (step S245). Accordingly, the master server330registers the information of the IPv6 terminal510, and provides the home-only IP address converting device100with the information about the registration. Accordingly, the home-only IP address converting device100receives the registration information, and provides the IPv6 terminal510with the received registration information (step S246).

Meanwhile, if it is determined that the second private IPv4 address is not registered in S243, the control unit110controls the second private acquiring unit124to be connected to the DHCPv4 server350and to request the DHCPv4 server350for the IPv4 address of the IPv6 terminal510in IPv4 system (step S247). Accordingly, the IPv4 address of the IPv6 terminal510provided by the DHCPv4 server350, i.e., the second private IPv4 address is stored in the mapping table of the storing unit140(step S249).

FIG. 10is a flowchart showing the method of the IPv4 terminal310for controlling the IPv6 terminal510in the home network system according to the present invention. First, the IPv4 terminal310requests the master server330for the private IPv4 address of the IPv6 terminal510(step S310). The master server330provides the IPv4 terminal310with the information about the registered IPv6 terminal510(step S330). Accordingly, based on the information provided, the IPv4 terminal310selects the control signal for controlling the IPv6 terminal510and then transmits the selected control signal to the home-only IP address converting device100so that the selected control signal can be transmitted to the IPv4 address (step S350). The home-only IP address converting device100transmits the control signal to the IPv6 terminal510having the IPv6 address that corresponds to the IPv4 address (step S370).

FIG. 11is a flowchart showing in detail the operation of the home-only IP address converting device100according to S350ofFIG. 10. First, having received with the control signal with respect to the IPv6 terminal510, the control unit110searches the mapping table of the storing unit140(step S361). The control unit110determines whether or not to register the IPv4 address corresponding to the IPv6 address of the IPv6 terminal510, the receiver of the control signal (step S363). If it is determined that the IPv4 address of the IPv6 terminal510, the receiver of the control signal, is registered, the control unit110transmits the received control signal to the IPv6 terminal510having the IPv6 address corresponding to the IPv4 address (step S365). Meanwhile, if it is determined that the IPv4 address of the IPv6 terminal510, the receiver of the control signal, is not registered, the control unit110discards the received control signal (step S367).

According to the present invention, the IPv6 address is generated through the network address provided by the network address providing unit130. The DHCPv4 server350allots the IPv4 address corresponding to the IPv6 address of the IPv6 terminal510. The IPv4 address and the IPv6 address of the IPv4 terminal310and the IPv6 terminal510are stored in the mapping table of the storing unit140, and the master server330manages and provides the registration information about the IPv4 terminal310and the IPv6 terminal510. As a result, there is no need to employ the DHCPv6 server and the DNSv6 server for communication.

Also, according to the present invention, since there is no need for the DHCPv6 server and the DNSv6 server in the home network system, cost for building network system can be reduced.

Also, omission of the DNSv6 server and the DHCPv6 server during the establishment of the home network for a communication between the IPv4 terminal310and the IPv6 terminal510can reduce the space that the system occupies.

Meanwhile, if added to the device for mounting the IPv6 addresses plus all the other devices that are required by the middleware to perform networking in the home network, the home network can provide users with a wide range of services while never disturbed by the characteristics of the devices and the IP address formats. Also, the service quality increases.