JP5439036B2 - COMMUNICATION SYSTEM, COMMUNICATION MANAGEMENT DEVICE, COMMUNICATION MANAGEMENT METHOD, AND COMMUNICATION MANAGEMENT PROGRAM - Google Patents

Description

  The present invention relates to a communication system, a communication management device, a communication management method, and a communication management program.

In recent years, with the development of information technology, many digital home appliances using digital related technology have been found in the home. Recently, a technique for connecting these digital home appliances to each other via a network and providing various functions has been proposed. For example, a media playback device (DMP: Digital Media Player) that plays back content such as video and music downloads content from a media server (DMS: Digital Media Server) that stores a large amount of content in a large storage area. To play.
In such a network of electrical appliances in the home (referred to as a home network), it has been studied to make each electrical appliance compatible and facilitate interconnection and communication between the electrical appliances. For example, Non-Patent Document 1 describes DLNA (Digital Living Network Alliance (registered trademark)) guidelines as a standard for home networks.

However, since the DLNA guidelines are mainly intended for use within a home network, electrical appliances could not discover and control electrical appliances in other networks connected via the Internet network. .
For such a problem, Patent Document 1 describes a proxy device that encapsulates a communication packet in a home network and transmits the encapsulated communication data to the Internet. In addition, it is described that this proxy device decapsulates communication data received from the Internet and transmits it to the home network. That is, this technique is a technique for connecting home networks using VPN.

JP 2008-236344 A

“DLNA Guidelines”, [online], Digital Living Network Alliance (registered trademark), [searched on February 27, 2009], Internet <http: // www. dlna. org / home>

However, the home networks to be connected are not limited to networks having different network addresses (referred to as different networks), and may be networks having the same network address (referred to as the same network). For example, when the technology described in Patent Document 1 is applied when connecting the same networks, the assigned addresses may overlap between the communication device in one network and the communication device in the other network. In this case, the connected home network has a drawback that the communication device cannot communicate accurately. In addition, it takes time to eliminate such address duplication.
Such a problem is not limited to the home network, and is the same for, for example, connection between LANs (Local Area Networks).
As described above, the conventional technique has a drawback that the communication device may not be able to communicate quickly and accurately when the networks are connected to each other.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a communication system, a communication management apparatus, and a communication management that enable communication apparatuses in the network to accurately communicate when the networks are connected to each other. A method and a communication management program are provided.

(1) The present invention has been made to solve the above-described problems, and the present invention manages a first communication address assigned to a first communication device connected to a first communication network. 1. A communication system comprising: a first communication management device; and a second communication management device that manages a second communication address assigned to a second communication device connected to a second communication network. Whether the network identification information indicated by the first communication address and the network identification information indicated by the second communication address are the same network identification information. If it is determined that the network determination unit and the network determination unit have the same network identification information, the first communication address and the second communication address And an address determination unit that determines whether or not the same communication address is present, and the first communication management device is configured to perform the first communication based on the determination results of the network determination unit and the address determination unit. A communication system comprising a connection setting unit for selecting a connection method for enabling communication between a communication device and the second communication device.
According to the above configuration, the communication system determines whether the network identification information indicated by the first communication address and the network identification information indicated by the second communication address are the same network identification information. If the same network identification information is determined, it is determined whether or not the first communication address and the second communication address have the same communication address, and the first communication address is determined based on the determination result. A connection method that enables communication between the communication device and the second communication device is selected. As a result, the communication system selects the connection method for the first communication network and the second communication network regardless of whether the same network identification information is assigned to the first communication network or the network to which the different network identification information is assigned. Thus, the first communication device and the second communication device can be communicated quickly and accurately.

(2) In the communication system described above, when the first communication management device or the second communication management device determines that the address determination unit has the same communication address, the second communication management device It is determined whether or not the same network address that is different from the communication address of the network and is the communication address of the network identification information indicated by the second communication address can be assigned to all of the first communication devices. A payout address search unit is provided, and the connection setting unit selects the connection method based on a determination result of the payout address search unit.
According to the above configuration, in the communication system, when the address determination unit determines that there is the same communication address, a communication address that is different from the second communication address and is indicated by the second communication address. It is determined whether or not the same network address as a communication address can be assigned to all of the first communication devices, and the connection method is selected based on the determination result. Accordingly, when the communication system can allocate the same network address to all of the first communication devices, the same network address is allocated to the first communication device, and the first network and the second network are assigned. Can be connected as the same network. In addition, for example, when the same network address cannot be assigned to all of the first communication devices, the communication system sets a communication address of network identification information other than the network identification information indicated by the second communication address. The first network and the second network can be connected as different networks by being assigned to one communication device. Therefore, the communication system can enable the first communication device and the second communication device to communicate quickly and accurately.

(3) Further, in the communication system according to the present invention, the first communication device is a communication device that performs multicast on a connected network and detects a communication device of a communication destination based on a response, and the connection The setting unit, when the payout address search unit determines that the same network address cannot be assigned to all of the first communication devices, the first communication device and the second communication device that performed the multicast After selecting the first connection method that enables communication as a device in the same network, and enabling the first communication device that has performed the multicast using the first connection method, Connection for changing the connection method between all of the first communication devices and the second communication device to a second connection method that enables communication as a different network Characterized in that it comprises an expression changing section.
According to the above configuration, when the communication system determines that the same network address cannot be assigned to all of the first communication devices, the first communication device and the second communication device that have performed the multicast Can be communicated using the first connection method, and thereafter, the connection method between all of the first communication devices and the second communication device is changed to the second connection method. Accordingly, the communication system can connect the first communication device that has performed the multicast to the second network in preference to the other first communication devices, and the first communication device that has performed the multicast. The communication device can be made to communicate more quickly.

(4) Further, according to the present invention, in the communication system described above, the first communication management device or the second communication management device is configured so that the payout address search unit assigns the same network address to all of the first communication devices. An address determination unit that issues two identical network addresses, and the first communication management device assigns one of the identical network addresses issued by the address determination unit to the network identical address. A formal address setting unit for deciding to assign to a connection device capable of communicating with the second communication device and deciding to assign another network identical address to the first communication device that has performed the multicast; The connection device and the first communication device that performed the multicast are connected to a network indicated by the same network address. Characterized in that it comprises a temporary identity network generation unit that registers as a device of a work, a.
According to the above configuration, the communication system assigns one of the same network addresses to a connection device that can communicate with the second communication device, and assigns the other network same address to the first network that has performed the multicast. Assigning to a communication device, the connection device and the first communication device are registered as network devices indicated by the same network address. Accordingly, the communication system can connect the connection device and the first communication device that has performed the multicast as a device of the same network as the second network. Further, the duplication of the first communication address assigned to the first communication device other than the first communication device that performed the multicast and the second communication address assigned to the second communication device is prevented. Can do.

(5) Further, in the communication system according to the present invention, the communication system includes a plurality of relay devices that relay communication data from the first communication device to the second communication device. The first communication device transmits the communication data including the number of relays indicating the number of the relay devices that relay the communication data, and the relay device relays the communication data so that the number of relay devices relays the communication data. When the number of communication data exceeds the number, the communication data is discarded, and the first communication management device includes a TTL extension processing unit that increases the number of relays.
According to the above configuration, since the communication system increases the number of relays of the communication data, the number of the relay devices increases when the first communication device and the second communication device are enabled to communicate. Even in this case, the communication data transmitted by the first communication device can be relayed and reliably received by the second communication device.

  (6) In the first communication management device that manages the first communication address assigned to the first communication device connected to the first communication network, the present invention indicates the first communication address. Network determination for determining whether the network identification information and the network identification information indicated by the second communication address assigned to the second communication device connected to the second communication network are the same network identification information And the address determination unit for determining whether the first communication address and the second communication address have the same communication address when the network determination unit and the network determination unit determine that the same network identification information is included. Based on the determination results of the network determination unit and the address determination unit, the first communication device and the second communication device can communicate with each other. A connection setting section for selecting a connection method, a first communication management apparatus comprising: a.

  (7) Further, the present invention provides a communication management method in a first communication management apparatus that manages a first communication address assigned to a first communication apparatus connected to a first communication network. The network identification information indicated by the first communication address is the same as the network identification information indicated by the second communication address assigned to the second communication device connected to the second communication network. When the first process for determining whether or not the network identification information is the same as the network identification information in the first process, the first communication address And a second process for determining whether or not the same communication address is present in the second communication address, and the first communication management device determines whether the determination result of the first process and the second process is Zui and a communication management method characterized by having a third step of selecting a connection method that enables communication between the first communication device and the second communication device.

  (8) According to the present invention, the computer of the first communication management apparatus that manages the first communication address assigned to the first communication apparatus connected to the first communication network is used as the first communication address. And whether the network identification information indicated by the second communication address assigned to the second communication device connected to the second communication network is the same network identification information. Address determination for determining whether the first communication address and the second communication address have the same communication address when the network determination means and the network determination means determine that the same network identification information is obtained. Means, based on the determination results of the network determination means and the address determination means, the first communication device and the second communication device Connection setting means for selecting a connection method that enables communication, a communication method management program to function as a.

  According to the present invention, the communication system can be connected to the first communication network and the second communication network regardless of whether the same network identification information is assigned to the first communication network or the second communication network. The first communication device and the second communication device can communicate quickly and accurately.

1 is a conceptual diagram of a communication system according to an embodiment of the present invention. It is another conceptual diagram of the communication system which concerns on this embodiment. It is a schematic block diagram which shows the structure of the media reproduction apparatus concerning this embodiment. It is a schematic block diagram which shows the structure of the DHCP server which concerns on this embodiment. It is the schematic which shows an example of the payout address table which concerns on this embodiment. It is a schematic block diagram which shows the structure of the 1st DLNA connection apparatus which concerns on this embodiment. It is a schematic block diagram which shows the structure of the network connection process part which concerns on this embodiment. It is a schematic block diagram which shows the structure of the connection setting part which concerns on this embodiment. It is a schematic block diagram which shows the structure of the communication data conversion part which concerns on this embodiment. It is a schematic block diagram which shows the structure of the media server which concerns on this embodiment. It is a schematic block diagram which shows the structure of the 2nd DLNA connection apparatus which concerns on this embodiment. It is a schematic block diagram which shows the structure of the network connection process part which concerns on this embodiment. It is a schematic block diagram which shows the structure of the connection setting part which concerns on this embodiment. It is a flowchart which shows an example of operation | movement of the communication system which concerns on this embodiment. It is a flowchart which shows an example of operation | movement of the provisional IP address payout process which concerns on this embodiment. It is a flowchart which shows an example of operation | movement of the formal IP address determination process which concerns on this embodiment. It is a flowchart which shows an example of operation | movement of the formal IP address determination process which concerns on this embodiment. It is a conceptual diagram of the formal IP address determination process which concerns on this embodiment. It is a conceptual diagram of the formal IP address determination process which concerns on this embodiment. It is a flowchart which shows an example of operation | movement of the formal IP address setting process which concerns on this embodiment. It is a flow figure showing an example of operation of temporary same NW mode allocation processing concerning this embodiment. It is a conceptual diagram of the formal IP address setting process which concerns on this embodiment. It is a conceptual diagram of the formal IP address setting process which concerns on this embodiment. It is a conceptual diagram of the temporary same NW mode allocation process which concerns on this embodiment. It is the schematic which shows an example of the payout address table which concerns on this embodiment. It is the schematic which shows another example of the payout address table which concerns on this embodiment. It is the schematic which shows another example of the payout address table which concerns on this embodiment. It is the schematic which shows another example of the payout address table which concerns on this embodiment. It is a flowchart which shows an example of the operation | movement of the VPN connection process which concerns on this embodiment. It is the schematic which shows an example of the NAT table which concerns on this embodiment. It is the schematic which shows an example of the reverse NAT conversion table which concerns on this embodiment. It is the schematic which shows the header information of the communication packet which concerns on this embodiment. It is a flow figure showing an example of operation of TTL extension processing concerning this embodiment. It is a flowchart which shows an example of communication of the search message which concerns on this embodiment. It is a flowchart which shows another example of communication of the search message which concerns on this embodiment. It is a flowchart which shows an example of operation | movement of a used formal IP address notification process and a used formal IP address collection | recovery process which concern on this embodiment.

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

<About communication systems>
FIG. 1 is a conceptual diagram of a communication system according to an embodiment of the present invention.
In this figure, the communication system includes two home networks H1 and H2. The two home networks H1 and H2 are respectively connected to a WAN (Wide Area Network) W1.

The home network H1 (first communication network) includes a media playback device (DMP: Digital Media Player) A11, A12 (first communication device), a DHCP (Dynamic Host Configuration Protocol) server B1, and a home gateway C1. . A device included in the home network H1 is connected to a LAN (Local Area Network) L1 and assigned a private IP address (such as a private IP address assigned a network address in a predetermined range). A closed network).
The home network H2 (second communication network) includes a media server (DMS: Digital Media Server) A21 (second communication device), a DHCP server B2, and a home gateway C2. A device included in the home network H2 is connected to the LAN L2. The home network H2 is a closed network.
Here, the network address of the private IP address used in the LAN L1 may be the same as the network address of the private IP address used in the LAN L2 (the home networks H1 and H2 are referred to as the same network), and may be different ( There are also home networks H1 and H2).

The media server A21 has a large-capacity storage area, and stores a large amount of content such as video and music in the storage area. Media playback devices A11 and A12 download and play back content from the media server A21. In order for the media playback devices A11 and A12 and the media server A21 to communicate, it is necessary to connect the home networks H1 and H2 in advance and enable communication.
In order to connect the home networks H1 and H2 in advance, the home gateway C1 and the home gateway C2 according to the present embodiment perform the following connection process.
First, the home gateway C1 transmits a connection request to the home gateway C2. In response to the connection request from the home gateway C1, the home gateway C2 determines a private IP address to be assigned in the home network H1. The home gateway C1 assigns a private IP address in the home network H1 based on the private IP address determined by the home gateway C2. The home gateway C1 selects a connection method with the home gateway C2 based on the private IP address determined by the home gateway C2.
Hereinafter, in the home network H1, a private IP address determined by the home gateway C2 and assigned by the home network H1 is referred to as a formal IP address. A private IP address other than the official IP address (before the home gateway C2 is determined) is referred to as a temporary IP address.

FIG. 2 is another conceptual diagram of the communication system according to the present embodiment.
In this figure, the home network H1 includes media playback devices A11 and A12, a DHCP server B1, and a home gateway C1. The home network H2 includes a media server A21, a DHCP server B2, and a home gateway C2.
The home gateway C1 includes a first DLNA (Digital Living Network Alliance (registered trademark)) connection device c1 (first communication management device) and a second DLNA connection device c2 (second communication management device). Consists of.

The media playback devices A11 and A12 transmit a search message that detects the media server and includes the destination information of the own device in a multicast packet. Further, the media playback devices A11 and A12 receive the response message from the media server A21 that has received the search message as a unicast packet. The media playback devices A11 and A12 extract the destination information of the media server A21 from the response message and communicate with the media server A21. That is, the media playback devices A11 and A12 perform multicasting to the connected network, and detect the communication destination media server A21 based on the response.
The media playback devices A11 and A12 download content from the media server A21 and play back the downloaded content.
The media playback devices A11 and A12 are, for example, a hard disk recorder, a television, a printer, or a personal computer. Further, the media playback devices A11 and A12 may be connected to the LAN L1 by wireless communication, and may be, for example, a mobile phone device or a mobile playback device that plays back video or music.

  The DHCP servers B1 and B2 pay out private IP addresses used in the LANs L1 and L2, respectively. The private IP addresses issued by the DHCP servers B1 and B1 can be registered from the first DLNA connection device c1 and the second DLNA connection device c2, respectively. The private IP address of each device issued by the DHCP servers B1 and B2 is registered in each device in the home networks H1 and H2, respectively. The functions of the DHCP servers B1 and B2 may be provided in the home gateways C1 and C2. Further, the DHCP servers B1 and B2 are not limited to the dynamic allocation of IP addresses, and may perform static allocation.

The first DLNA connection device c1 performs a connection process with the second DLNA connection device c2. FIG. 2 shows that, as a result of this connection processing, the first DLNA connection device c1 and the second DLNA connection device c2 are connected by VPN (Virtual Private Network). There are two types of VPN connections.
One is, for example, a layer 3-VPN that registers routing information between connected networks in a router device (not shown) in the WAN W1 and fixes IP packet routing. The other is, for example, that a TAP that virtually implements the operation of a network device with software adds Layer 2 header information to a communication frame of Layer 2 (data link layer), thereby realizing Layer 2 for realizing VPN. -VPN. Layers 2 and 3 indicate the second layer (data link layer) and the third layer (network layer) of the OSI reference model, respectively. In addition, you may implement | achieve VPN using the communication technique regarding the layer 2 or more layers, for example, MPLS (Multi-Protocol Label Switching) as Layer 2-VPN.

The first DLNA connection device c1 generates a layer 2-VPN when the home networks H1 and H2 are the same network. On the other hand, the first DLNA connection device c1 generates a layer 3-VPN when the home networks H1 and H2 are different networks.
A connection method for connecting to another network using the layer 2-VPN is called “same segment method” (first connection method), and a connection method for connecting to another network using the layer 3-VPN is “ This is called a “routing method” (second connection method). In particular, a method of performing multicasting to other networks using Layer 3-VPN is referred to as a “multicast routing method”.

  The media server A21 receives the search message transmitted from the media playback device A11 or A12, and extracts the destination information of the media playback device A11 or A12. The media server A21 generates a response message including the destination information of the own device, and transmits it as a unicast packet to the destination indicated by the extracted destination information.

  Details of the devices in the home networks H1 and H2 will be described below. Here, since the media playback devices A11 and A12 in FIGS. 1 and 2 have the same configuration, they will be described as the media playback device a1. The media server A21 is referred to as a media server a2. The DHCP servers B1 and B2 are referred to as DHCP servers b1 and b2, respectively.

<Configuration of Media Playback Device a1>
First, the media playback device a1 will be described.
FIG. 3 is a schematic block diagram showing the configuration of the media playback device a1 according to this embodiment.
In this figure, a media playback device a1 includes a LAN connection unit a10, an address update unit a111, an address information storage unit a112, a media server detection unit a113, a media server information storage unit a114, a content acquisition unit a115, a content playback unit c116, and An output unit a117 is included.

The LAN connection unit a10 is a network interface card connected to a LAN cable. The media playback device a1 communicates with other devices via the LAN connection unit a10.
When the media playback device a1 is connected to the LAN, the address update unit a111 transmits an address issue request for requesting a private IP address to the DHCP server B1. The address update unit a111 extracts the IP address information issued to the own device from the response of the address issue request and stores it in the address information storage unit a112. This IP address information is information on the private IP address, the payout date and time, and the lease period in the LAN L1 (see FIG. 5). Here, the payout date and time indicates the date and time when the private IP address is paid out, and the lease period indicates a period during which the private IP address can be used.

Further, the address update unit a111 extracts the IP address information stored in the address information storage unit a112 periodically or when generating communication data, and determines whether or not the lease period has elapsed from the date and time when the private IP address is issued. To do. When the lease period has elapsed, the address update unit a111 transmits a private IP address (referred to as a used IP address) for which the lease period has elapsed to the first DLNA connection apparatus c1. In this case, the address update unit a111 transmits an address payout request to the DHCP server B1. The address update unit a111 extracts the IP address information from the response to the address issue request and stores it in the address information storage unit a112.
In this way, the media playback device a1 performs the IP address information update process after the lease period of the IP address information has elapsed.

  In addition, in the said embodiment, the address update part a111 demonstrated the case where the update process of IP address information was performed after the lease period of IP address information. However, the present invention is not limited to this. For example, when the address update unit a111 receives the IP address information from the DHCP server B1, the address update unit a111 may update it at any time regardless of the lease period. Further, the address update unit a111 transmits an address issue request immediately after the search message is transmitted or after a certain period of time has elapsed since the search message is transmitted, and the IP address information transmitted by the DHCP server B1 in response to the address issue request. May be received and stored in the address information storage unit a112.

The media server detection unit a113 extracts the private IP address of the own device from the IP address information stored in the address information storage unit a112. The media server detection unit a113 generates a search message including the extracted private IP address, and multicasts the generated search message into the LAN via the LAN connection unit a10. This search message transmission process is performed, for example, periodically or triggered by a user operation such as selecting a content by the user.
The media server detection unit a113 receives the response message of the search message by unicast. The media server detection unit a113 extracts the destination information of the media server a2 from the response message and stores it in the media server information storage unit a114. That is,

The content acquisition unit a115 transmits a content request for requesting content transmission to the destination indicated by the destination information of the media server a2 stored in the media server information storage unit a114. When the content acquisition unit a115 receives a response message indicating permission of download, the content acquisition unit a115 downloads content data from the destination media server a2 included in the response message, and outputs the content data to the content reproduction unit a116.
The content reproduction unit a116 reproduces the content data input from the content acquisition unit a115 and outputs the content data at the output unit a117.
The output unit a117 is a display or a speaker, and outputs the content data output from the content playback unit b116 as video or sound.

<Configuration of DHCP server b1>
Next, the DHCP server b1 will be described.
FIG. 4 is a schematic block diagram showing the configuration of the DHCP server b1 according to this embodiment.
In this figure, the DHCP server b1 includes a LAN connection unit b10, a reservation address information acquisition unit b111, a reservation address information storage unit b112, an address issue unit b113, a lease period setting unit b114, a payout address information storage unit b115, and a payout address information. The notification unit b116 is included.
The LAN connection unit b10 is a network interface card connected to a LAN cable. The DHCP server b1 communicates with other devices via the LAN connection unit b10.

The reserved address information acquisition unit b111 acquires the reserved address information from the first DLNA connection device c1 via the LAN connection unit b10. The reserved address information is information on an IP address to be issued to an address issuing unit b113 described later, and includes information on an IP address, a device MAC address, and a lease period. Here, the device MAC address is a hardware-specific physical address of the network device and is information for identifying the hardware. Note that the reserved address information is IP address information of an official IP address, as will be described later.
The reserved address information acquisition unit b111 stores the acquired reserved address information in the reserved address information storage unit b112.

The address issue unit b113 receives the address issue request from the media playback device a1 via the LAN connection unit a10. The address issue unit b113 extracts the device MAC address from the received address issue request. The address issuing unit b113 reads the reserved address information from the reserved address information acquisition unit b111, and determines whether there is reserved address information including the extracted device MAC address.
If it is determined that there is reserved address information, the address issuing unit b113 transmits the reserved address information including the extracted device MAC address as IP address information to the media playback device a1 that has made the address issue request. On the other hand, if it is determined that there is no reserved address information, the address issuing unit b113 performs a provisional IP address issuing process described later, and issues IP address information. Note that the IP address information to be paid out in this case is the IP address information of the temporary IP address.

The lease period setting unit b114 sets a lease period shorter than the lease period of the formal IP address as the lease period of the temporary IP address in the provisional IP address issuing process performed by the address issuing unit b113. As a result, it is possible to cause the media playback device a1 to transmit an address issue request in a shorter period than the lease period of the official IP address, and to increase the frequency of updating the temporary IP address.
The address payout unit b113 stores the payout IP address information in the payout address information storage unit b115 (see FIG. 5).
When the address paying unit b113 pays out the IP address information, the paying address information notifying unit b116 transmits the IP address information stored in the paying address information storage unit b115 to the media reproducing device a1 as the paying address information.

  FIG. 5 is a schematic diagram illustrating an example of a payout address table according to the present embodiment. As shown in the figure, the payout address table has columns of items of private IP address, device MAC address, payout date and time, and lease period. In the payout address table, payout address information is stored for each private IP address.

For example, the payout address information in the first line in FIG. 5 indicates the payout address information paid out to the media playback device A11 in FIG. This payout address information indicates that the private IP address “PA_A11” (for example, 192.168.1.1) has been paid out to the media playback device A11 having the device MAC address “MAC_A11”. The payout address information indicates that the date and time when the IP address information is paid out is the payout date and time “15:11 on March 15,” and the lease period is “60 minutes”.
Note that “192.168.1.0” (subnet mask 255.255.255.0) at the beginning of the private IP address is the network address.

<Configuration of First DLNA Connection Device c1>
Next, the first DLNA connection device c1 will be described.
FIG. 6 is a schematic block diagram showing the configuration of the first DLNA connection device c1 according to the present embodiment.
In this figure, the first DLNA connection device c1 includes a LAN connection part c10, a payout address acquisition part c111, a payout address information storage part c112, a network connection processing part c12, a formal address storage part c124, a provisional address storage part c125, a connection. It includes a setting unit c13, a temporary device c14 (connection device), a communication data conversion unit c15, and a WAN connection unit c16.

The LAN connection unit c10 is a network interface card connected to a LAN cable. The first DLNA connection device c1 communicates with other devices via the LAN connection unit c10.
The payout address acquisition unit c111 receives the payout address information transmitted by the DHCP server B1 via the LAN connection unit c10 and stores it in the payout address information storage unit c112. Also, the payout address acquisition unit c111 outputs the received payout address information to the connection setting unit c13.

The network connection processing unit c12 generates temporary IP address information based on the payout address information stored in the payout address information storage unit c112 and the formal address stored in the formal address information storage unit c124, and stores the temporary IP address information storage Store in the part c125.
When receiving the search message transmitted from the media playback device a1, the network connection processing unit c12 generates a connection request. This connection request includes provisional IP address information stored in the provisional IP address information storage unit c125. The generated connection request is transmitted to the second DLNA connection device c2 via the WAN connection unit c16.
Further, the network connection processing unit c12 receives a formal IP address response that is a response to the connection request from the second DLNA connection device c2. The network connection processing unit c12 stores the formal IP address included in the received formal IP address response in the formal address information storage unit c124, and outputs the connection mode information included in the formal IP address response to the connection setting unit c13. .
This connection mode information is information indicating the relationship between the home networks H1 and H2. The connection mode information includes a “different NW (NetWork)” mode indicating that the home networks H1 and H2 are different networks and a “same NW” mode indicating the same network. In addition, there is a “temporarily identical NW” mode in which the same network is temporarily set and then different networks are set.
Details of the configuration of the network connection processing unit c12 will be described later.

Based on the connection mode information input from the network connection processing unit c12, the connection setting unit c13 determines the assignment of the formal IP address stored in the formal IP address information storage unit c124 to the media playback device a1 having the temporary IP address. To do. The connection setting unit c13 generates reserved address information indicating the determined assignment, and transmits it to the DHCP server b1 via the LAN connection unit c10.
Further, as will be described later, when the connection mode is “temporarily identical NW”, the connection setting unit c13 registers one of the official IP addresses as the IP address of the LAN connection unit c10. For example, an IP address is registered using an IP alias function called by an ifconfig command.
The LAN connection unit c10 in which the IP address is registered in this manner operates as if a network interface card having the registered IP address is newly added. This virtual network interface card is called a temporary device. Note that the IP address of one temporary device may be registered in one network interface card. In this case, the temporary device corresponds to a network interface card that is an actual physical device. Hereinafter, registering an IP address in the LAN connection unit c10 is referred to as creating a temporary device.

The connection setting unit c13 selects a connection method (same segment method, routing method) according to the connection mode information input from the network connection processing unit c12. The connection setting unit c13 generates a layer 2-VPN or a layer 3-VPN based on the selected connection method, and generates communication data conversion information used for conversion of communication information in the communication data. The connection setting unit c13 outputs the generated communication data conversion information to the communication data conversion unit c15.
Details of the configuration of the connection setting unit c13 will be described later.

The communication data conversion unit c15 converts the destination information in the communication packet based on the communication data conversion information input from the connection setting unit c13. Details of the configuration of the communication data conversion unit c15 will be described later.
The WAN connection unit c16 is a network interface card connected to a WAN line cable. The first DLNA connection device c1 communicates with other devices via the WAN connection unit c16.

<Regarding the configuration of the network connection processing unit c12>
Details of the network connection processing unit c12 will be described below.
FIG. 7 is a schematic block diagram showing the configuration of the network connection processing unit c12 according to the present embodiment. In this figure, the network connection processing unit c12 includes a connection processing unit c121, a connection mode changing unit c122, and a connection mode storage unit c123.

 The connection processing unit c121 extracts the private IP address of the media playback device a1 that has transmitted the search message from the search message received via the LAN connection unit c10. Further, the connection processing unit c121 reads the formal IP address from the formal address information storage unit c124, and determines whether or not the extracted private IP address is included in the read formal IP address. When it is determined that the IP address is included in the official IP address, that is, when it is determined that the private IP address of the search message transmission source is an official IP address, the connection processing unit c121 sends the received search message to the communication data conversion unit c15. Output (not shown).

On the other hand, when it is determined that it is not included in the official IP address, that is, when it is determined that the private IP address of the search message transmission source is a temporary IP address, the connection processing unit c121 generates a connection request as follows, Transmit to the second DLNA connection device c2.
First, the connection processing unit c121 reads the payout address information from the payout address information storage unit c112. The connection processing unit c121 extracts payout address information whose private IP address is not an official IP address from the read payout address information (the extracted information is referred to as provisional IP address information). The connection processing unit c121 stores the extracted provisional IP address information in the provisional address information storage unit c125. In addition, the connection processing unit c121 generates a connection request including the extracted provisional IP address information, and transmits the connection request to the second DLNA connection device c2 via the WAN connection unit b16.

The connection processing unit c121 receives a formal IP address response that is a response to the connection request from the second DLNA connection device c2 via the WAN connection unit c16. The connection processing unit c121 extracts the formal IP address and the connection mode from the received formal IP address response. The connection processing unit c121 stores the extracted formal IP address in the formal address information storage unit c124. In addition, the connection processing unit c121 outputs the extracted connection mode to the connection mode changing unit c122.
In addition, the connection processing unit c121 transmits the connection mode input from the connection mode changing unit c122 described later to the second DLNA connection device c2. Also, when the connection processing unit c121 receives the used IP address from the media playback device a1, the connection processing unit c121 performs a used formal IP address notification process. The used formal IP address notification process will be described later.

The connection mode changing unit c122 outputs the connection mode input from the connection processing unit c121 to the connection setting unit c13, and stores it in the connection mode storage unit c123.
In addition, when the connection mode stored in the connection mode storage unit c123 is the “temporarily identical NW” mode, the connection mode changing unit c122 outputs payout address information stored in the payout address information storage unit c112, and a connection setting unit c13 described later. The connection mode is changed based on the reserved address information stored in the reserved address information storage unit c134. The connection mode changing unit c122 outputs the changed connection mode to the connection processing unit c121 and the connection setting unit c13.

<About the configuration of the connection setting unit c13>
Details of the connection setting unit c13 will be described below.
FIG. 8 is a schematic block diagram illustrating the configuration of the connection setting unit c13 according to the present embodiment.
In this figure, the connection setting unit c13 includes a formal address setting unit C13, a communication data conversion setting unit c136, and a VPN setting unit c137. The formal address setting unit C13 includes an address determination unit c131, a network address determination unit c132, a reserved address information setting unit c133, a reserved address information storage unit c134, and a temporary device generation unit c135 (temporary identical network generation unit). The

When the connection mode is input from the network connection processing unit c122, the formal address setting unit C13 performs the following formal IP address setting process.
The address determination unit c131 determines whether or not the formal IP address stored in the formal address information storage unit c124 matches the temporary IP address stored in the temporary address information storage unit c125.
The network address determination unit c132 determines whether the formal IP address stored in the formal address information storage unit c124 and the temporary IP address stored in the temporary address information storage unit c125 are the same network address It is determined whether the network addresses are the same or different.

The reserved address information setting unit c133 reads the device MAC address of the temporary address information stored in the temporary address information storage unit c125. The reserved address information setting unit c133 associates the formal IP address stored in the formal address information storage unit c124 with the read device MAC address based on the determination results of the address determination unit c131 and the network address determination unit c132. That is, the reserved address information setting unit c133 determines assignment of the formal IP address stored in the formal IP address information storage unit c124 to the media playback device a1 having the temporary IP address.
The reserved address information setting unit c133 generates reserved address information in which the formal IP address is associated with the device MAC address, and transmits the reserved address information to the DHCP server b1 via the LAN connection unit c10. The reserved address information setting unit c133 stores the generated reserved address information in the reserved address information storage unit c134.
Further, the reserved address information setting unit c133 determines a formal IP address to be assigned to the temporary device c14 when the connection mode is the “temporary same NW” mode. The reserved address information setting unit c133 outputs the determined formal IP address to the temporary device generation unit c135.

The temporary device generation unit c135 generates the temporary device c14 using the official IP address input from the reserved address information setting unit c133. In addition, the temporary device generation unit c135 registers the device MAC address and the formal IP address of the media playback device a1 to be connected to the home network H2 via the temporary device c14 in the temporary device c14. In addition, the temporary device generation unit c135 outputs information in which the formal IP address of the temporary device is associated with the device MAC address to the reserved address information setting unit c133. Based on this information, the reserved address information setting unit c133 generates reserved address information of the temporary device and registers it in the DHCP server b1.
Through the registration performed by the temporary device generation unit c135 (referred to as connecting the temporary device c14 and the media playback device a1), the media playback device a1 is registered as a device on the same network as the temporary device. As a result, the temporary device c14 can transmit the communication data transmitted from the home network H2 to the media playback device A11 having the registered device MAC address.
Details of the formal IP address setting process performed by the formal address setting unit C13 will be described later.

  The communication data conversion setting unit c136 selects a connection method according to the connection mode input from the network connection processing unit c12. For example, when the connection mode is the “different NW” mode, the communication data conversion setting unit c136 selects “routing method”. When the connection mode is the “same NW” mode or the “temporary same NW” mode, the communication data conversion setting unit c136 selects “same segment method”. That is, the connection method between the home networks H1 and H2 is selected based on the communication mode.

The communication data conversion setting unit c136 also has a NAT (Network) associated with the private IP address of the payout address information input from the payout address information acquisition unit c111 and the global IP address of the own device set in the WAN connection unit c16. Address Translation) information is generated.
Further, when the connection mode is the “different NW” mode, the communication data conversion setting unit c136 reverses the IP address of the device of the home network H2 and the virtual IP address of the network address of the home network H1 in association with each other. Generate NAT conversion information. The communication data conversion setting unit c136 communicates with the second DLNA connection device c2 and acquires the IP address of the device of the home network H2.
The communication data conversion setting unit c136 outputs the selected connection method, NAT information, and inverse NAT conversion information to the communication data conversion unit c15 as address conversion information. Further, the communication data conversion setting unit c136 outputs the selected connection method and the global IP address of the own device to the VPN setting unit c137.

The VPN setting unit c137 transmits the connection mode and connection method input from the communication data conversion setting unit c136 to the second DLNA connection device c2. The VPN setting unit c137 communicates with the second DLNA connection device c2 to generate a VPN corresponding to the connection method.
For example, in the case of the connection method “routing method” input from the communication data conversion setting unit c136, the VPN setting unit c137 acquires the global IP address of the second DLNA connection device c2. The VPN setting unit c137 transmits the acquired global IP address of the second DLNA connection device c2 and the global IP address of the own device input from the communication data conversion setting unit c136 to the router device in the WAN W1. The router device generates a layer 3-VPN between the first DLNA connection device c1 and the second DLNA connection device c2.
In the case of the connection method “same segment method” input from the communication data conversion setting unit c136, the VPN setting unit c137 performs TAP-ETH bridge setting to be described later in the communication data conversion unit c15.
Details of the VPN connection process performed by the VPN setting unit c137 will be described later.

<About the configuration of the communication data conversion unit c15>
Details of the communication data conversion unit c15 will be described below.
FIG. 9 is a schematic block diagram illustrating a configuration of the communication data conversion unit c15 according to the present embodiment.
In this figure, a communication data conversion unit c15 includes a conversion method selection unit c151, an inverse NAT conversion information storage unit c152, a NAT information storage unit c153, a routing method conversion unit c154, a TTL (Time To Live) extension processing unit c155, and the same. A segment system conversion unit c156 is included.

When the connection method input from the connection setting unit c13 is “routing method”, the conversion method selection unit c151 causes the routing method conversion unit c154 to relay communication data. On the other hand, when the connection method is the “same segment method”, the same segment method conversion unit c 156 relays communication data.
The reverse NAT conversion information storage unit c152 and the NAT information storage unit c153 store the reverse NAT conversion information and the NAT information input from the connection setting unit c13, respectively.

Communication data transmitted from the media playback device a1 to the media server a2 and communication data transmitted from the media server a2 to the media playback device a1 are input to the routing method conversion unit c154. The routing method conversion unit c154 converts destination information in the input communication data based on NAT information stored in the NAT information storage unit c153 (referred to as NAT conversion).
Further, the routing method conversion unit c154 converts the IP address of the device of the home network H2 that is the source IP address in the communication packet based on the reverse NAT conversion information stored in the reverse NAT conversion information storage unit c152. It is converted into a virtual IP address of the network address of the network H1. Thus, even if the media playback device a1 receives communication data only when the IP address of the own device and the IP address of the transmission source are the same network address, the communication packet subjected to this conversion can be received. . That is, even a device that receives only communication packets from the home network H1 device can receive communication packets from the home network H2 device. Details of the multicast routing process performed by the routing method conversion unit c154 will be described later.

The TTL extension processing unit c155 stores the number of reception times and the reception time of the search message input from the network connection unit c12. The TTL extension processing unit c155 determines whether to extend the TTL (number of relays) (increase the TTL value) based on the stored number of receptions and reception time. The TTL extension processing unit c155 extends the TTL based on the determination result. The TTL is a value representing the valid period of the communication packet, and the value decreases by 1 each time the router is passed once.
By performing this TTL extension process, even if the TTL value set in the search message is smaller than the number of routers between the second DLNA connection device c2, the TTL value is increased and the search is performed. The message can be reliably transmitted to the second DLNA connection device c2. Details of the TTL extension processing performed by the TTL extension processing unit c155 will be described later.

  The same segment scheme conversion unit c156 has a TAP function, and adds layer 2 header information to the communication frame according to the setting from the connection setting unit c13 (referred to as TAP-ETH bridge setting). Also, the same segment scheme conversion unit c156 performs NAT conversion of the communication packet based on the NAT information, similarly to the routing scheme conversion unit c154.

<About the configuration of the media server a2>
Hereinafter, devices in the home network H2 will be described. First, the media server a2 will be described. Note that the configuration and functions of the DHCP server b2 are the same as the configuration and functions of the DHCP server b1, and therefore the description of the DHCP server b2 is omitted.

  FIG. 10 is a schematic block diagram showing the configuration of the media server a2 according to this embodiment. Comparing the media server a2 (FIG. 10) and the media playback device a1 (FIG. 3), the LAN connection unit a10, the address update unit a111, and the address information storage unit a112 are the same. The description of the same function as the media playback device a1 is omitted.

The access control unit a214 extracts the transmission source IP address of the communication data. When the network address of the extracted source IP address is the network address of the home network H2, the access control unit a214 permits reception of communication data and outputs the communication data to each unit of the media server a2. On the other hand, when the network address of the extracted source IP address is not the network address of the home network H2, the access control unit a214 rejects reception of communication data.
In the present embodiment, a second DLNA connection device c2 described later has the same function as the communication data conversion unit c15 of the first DLNA connection device c1. That is, when the transmission source of the communication data from the media playback device a1 is the IP address of the device of the home network H1, the second DLNA connection device c2 converts it to the virtual IP address of the network address of the home network H2. Therefore, the media server a2 can receive communication data from the media playback device a1 even if the home networks H1 and H2 are different networks.

  The search message response unit a213 receives the search message from the media playback device a1 via the access control unit a214. The search message response unit a213 extracts transmission destination information from the received search message. Further, the search message response unit a213 extracts the private IP address of the own device from the IP address information stored in the address information storage unit a112. The search message response unit a213 generates a response message including the extracted private IP address of the own device, which is a response message whose destination is the transmission source of the extracted destination information. The search message response unit a213 unicasts the generated search message via the LAN connection unit a10.

  When the content transmission unit a215 receives the content request from the media playback device a1, the content transmission unit a215 determines whether to permit the content download based on the load status of the own device and the number of connections from other devices, for example. If the content transmission unit a215 determines that the download is permitted, the content transmission unit a215 transmits a response message indicating that the download is permitted to the media playback device a1 that transmitted the content request. Further, the content transmission unit a215 permits the media playback device a1 that has received the response message to download the content stored in the content storage unit a216.

<Configuration of Second DLNA Connection Device c2>
Next, the second DLNA connection device c2 will be described.
FIG. 11 is a schematic block diagram showing the configuration of the second DLNA connection device c2 according to this embodiment. When the second DLNA connection device c2 (FIG. 10) is compared with the first DLNA connection device c1 (FIG. 6), the network connection processing unit c22 and the connection setting unit c23 are different. However, the functions of other components (LAN connection unit c10, payout address acquisition unit c111, payout address information storage unit c112, communication data conversion unit c15, and WAN connection unit c16) are the same as those of the first DLNA connection device c1. It is. A description of the same functions as those of the first DLNA connection device c1 is omitted.

<Configuration of network connection processing unit c22>
Details of the network connection processing unit c22 will be described below.
FIG. 12 is a schematic block diagram illustrating the configuration of the network connection processing unit c22 according to the present embodiment.
In this figure, the network connection processing unit c22 includes a connection processing unit c221 and a formal address issuing unit C22. The formal address payout unit C22 includes a network determination unit c222, an address determination unit c223, a payout address search unit c224, a formal address determination unit c225, a connection mode storage unit c226, and a formal address storage unit c227.

The connection processing unit c221 receives the connection request from the first DLNA connection device c1 via the WAN connection unit c16. The connection processing unit c221 extracts provisional IP address information included in the received connection request and outputs the temporary IP address information to the network determination unit c222.
Further, the connection processing unit c221 generates a formal IP address response including the formal IP address input from the formal address selection unit c224 and the connection mode in response to the connection request. The connection processing unit c221 transmits the generated formal IP address response to the media playback device a1 that is the transmission source of the connection request via the WAN connection unit c16.
In addition, the connection processing unit c221 transmits the formal IP address input from the formal address selection unit c224 to the DHCP server b2. The DHCP server b2 stores the received official IP address in the payout address information storage unit b115 (see FIG. 4) as a payout IP address. That is, the connection processing unit c221 registers the official IP address in the DHCP server b2 as the issued IP address.
In addition, the connection processing unit c221 performs a used formal IP address collection process described later.

  In the network determination unit c222, the network address (network identification information) of the provisional IP address input from the connection processing unit c221 is the same as the network address of the private IP address of the payout address information stored in the payout address information storage unit a112. It is determined whether it is a network address. That is, it is determined whether or not the home network H1 is the same network as the home network H2. The network determination unit c222 outputs the provisional IP address, the private IP address of the payout address information, and the determination result to the address determination unit c223.

  The address determination unit c223 performs the following process when the network determination unit c222 determines that the home network H1 and the home network H2 are the same network. The address determination unit c223 determines whether or not the temporary IP address input from the network determination unit c222 and the private IP address of the payout address information have the same IP address. That is, the address determination unit c223 determines whether there is a conflicting IP address between the temporary IP address of the home network H1 and the temporary IP address of the home network H2. The address determination unit c223 outputs the provisional IP address, the private IP address of the payout address information, and the determination result made by the network determination unit c222 and the address determination unit c223 to the payout address search unit c224.

The payout address search unit c224 performs the following processing when the address determination unit c223 determines that there is a conflict between the provisional IP address of the home network H1 and the provisional IP address of the home network H2.
The payout address search unit c224 sends a payable address request including the provisional IP address to the DHCP server B2 via the LAN connection unit c10. In response to this payable address request, the payout address search unit c224 requests an IP address (referred to as a payable IP address) that is an IP address that can be paid out by the DHCP server B2, excluding the IP address that has already been paid out. The payout address search unit c224 receives a response to the payable address request from the DHCP server B2, and extracts a payable IP address.

  The payout address search unit c224 calculates the number of payable IP addresses (hereinafter referred to as payable IP addresses H2) having the same network address as the network address of the home network H2 among the extracted payable IP addresses. Further, the payout address search unit c224 calculates the number of provisional IP addresses input from the address determination unit c223. The payout address search unit c224 determines whether the calculated number of payable IP addresses H2 is equal to or greater than the calculated number of provisional IP addresses. When the number of payable IP addresses H2 is equal to or greater than the number of provisional IP addresses, the formal address determining unit c225 uses a payable IP address having the same network address as the network address of the home network H2, as will be described later. Determine as. In other words, the payout address search unit c224 determines whether or not the payout IP address (same network address) of the same network address as that of the home network H2 can be paid out to all of the media playback devices a1 as an official IP address. To do.

If the payout address search unit c224 determines that the payable IP address of the same network address as that of the home network H2 cannot be paid out as an official IP address, whether or not the number of payable IP addresses H2 is two or more. Determine whether. When the number of payable IP addresses H2 is two or more, as will be described later, the formal address determination unit c225 determines the two payable IP addresses H2 as formal IP addresses. That is, the payout address search unit c224 determines whether or not two payable IP addresses having the same network address as the home network H2 can be assigned.
The payout address search unit c224 outputs the provisional IP address, the private IP address of the payout address information, and the determination result made by the network determination unit c222, the address determination unit c223, and the payout address search unit c224 to the formal address determination unit c225. To do.
The address determination process performed by the formal address assignment unit C22 will be described together with the operation of the formal IP address determination process described later.

The formal address determination unit c225 determines the connection mode based on the determination results performed by the network determination unit c222, the address determination unit c223, and the payout address search unit c224, and stores the determined connection mode in the connection mode storage unit c226. The formal address determination unit c225 determines a formal IP address based on the determined connection mode. The formal address determination unit c225 outputs the determined formal IP address to the connection processing unit c221.
The operation of the formal IP address determination process performed by the formal address assignment unit C22 will be described later.

<About the configuration of the connection setting unit c23>
Details of the connection setting unit c23 will be described below.
FIG. 13 is a schematic block diagram illustrating a configuration of the connection setting unit c23 according to the present embodiment.
In this figure, the connection setting unit c23 includes a router setting unit c231 and a communication data conversion setting unit c232.

The router setting unit c231 outputs the connection mode and connection method received from the first DLNA connection device c1 to the communication data conversion setting unit c232. The router setting unit c231 communicates with the first DLNA connection device c1 to generate a VPN corresponding to the connection method.
The communication data conversion setting unit c232 generates NAT information associated with the private IP address of the payout address information input from the payout address information acquisition unit c111 and the global IP address of the own device set in the WAN connection unit c16. .

Further, when the connection mode input from the router setting unit c231 is the “different NW” mode, the communication data conversion setting unit c232 includes the IP address of the device of the home network H1 and the virtual IP address of the network address of the home network H2. Are generated in association with inverse NAT conversion information. The communication data conversion setting unit c232 communicates with the first DLNA connection device c1 and acquires the IP address of the device of the home network H1.
The communication data conversion setting unit c232 outputs the connection mode, NAT information, and inverse NAT conversion information as address conversion information to the communication data conversion unit c15.

<Operation of communication system>
Hereinafter, the operation of the communication system will be described. First, an outline of the operation of the entire communication system will be described.
FIG. 14 is a flowchart showing an example of the operation of the communication system according to the present embodiment.

(Step S101) The media playback device a1 makes an address issue request when connected to the home network H1. Then, it progresses to step S11.
(Step S11) The DHCP server b1 performs provisional IP address issue processing. Details of the provisional IP address issuing process will be described later. Thereafter, the process proceeds to step S102.
(Step S102) The media server a2 makes an IP address request when connected to the home network H2. Thereafter, the process proceeds to step S12.
(Step S12) The DHCP server b2 performs provisional IP address issue processing. Thereafter, the process proceeds to step S103.
Note that there is no dependency relationship between the processing of step S101 and step S11 and the processing of step S102 and step S12, and the order of these processing may be reversed.

(Step S103) The media playback device a1 multicasts a search message. Thereafter, the process proceeds to step S104.
(Step S104) The first DLNA connection device c1 generates and transmits a connection request. Thereafter, the process proceeds to step S13.
(Step S13) The second DLNA connection device c2 performs a formal IP address determination process. Details of the formal IP address determination process will be described later. The second DLNA connection device c2 transmits a formal IP address response. Thereafter, the process proceeds to step S14.
(Step S14) The first DLNA connection device c1 performs a formal IP address setting process. Details of the formal IP address setting process will be described later. The first DLNA connection device c1 causes the DHCP server b1 to issue an official IP address. Thereafter, the process proceeds to step S15.

(Step S15) The first DLNA connection device c1 performs VPN connection processing. Details of the VPN connection process will be described later. Thereafter, the process proceeds to step S105.
(Step S105) The media playback device a1 and the media server a2 perform communications such as a search message, a content request, and a content download via the VPN generated in Step S15. Thereafter, the process proceeds to step S106.
(Step S106) The media playback device a1 transmits information on the used IP address. Thereafter, the process proceeds to step S16.
(Step S16) The first DLNA connection device c1 performs a used formal IP address notification process. Details of the used formal IP address notification process will be described later. The first DLNA connection device c1 notifies a used formal IP address that is a used IP address and is a formal IP address. Thereafter, the process proceeds to step S17.
(Step S17) The second DLNA connection device c2 performs a used formal IP address collection process. Details of the used formal IP address collection processing will be described later.

<Provisional IP address issue processing>
Details of the provisional IP address issue processing in steps S11 and S12 in FIG. 14 will be described below.
FIG. 15 is a flowchart showing an example of the operation of the provisional IP address issue process according to the present embodiment. The provisional IP address issuing process is a process performed by the DHCP server b1 (FIG. 4), and will be described with reference to FIG.

(Step S1101) The address issue unit b113 of the DHCP server b1 extracts the IP address of the transmission source from the address issue request. The address payout unit b113 determines whether or not the extracted IP address of the transmission source is included in the IP address of the payout address information stored in the payout address information storage unit b115. If it is determined that the IP address is included in the payout address information (YES), the process proceeds to step S1102. On the other hand, if it is determined that the IP address is not included in the payout address information (NO), the process proceeds to step S1104.

(Step S1102) The address issuing unit b113 extracts the source IP address and device MAC address from the address issue request. The address issue unit b113 determines whether or not the correspondence between the extracted IP address and the device MAC address matches the correspondence between the IP address and the device MAC address in the payout address information. If it is determined that the correspondence matches (YES), the process proceeds to step S1103. On the other hand, if it is determined that the correspondence does not match (NO), the process proceeds to step S1104.
(Step S1103) The address issue unit b113 generates IP address information having the same IP address as the source IP address extracted from the address issue request, and transmits the IP address information to the source media playback device a1. That is, the IP address is continuously paid out. Thereafter, the process ends.

(Step S1104) The lease period setting unit b114 sets the lease period of the IP address to be paid out in step S1105 to a period shorter than the lease period of the official IP address. Thereafter, the process proceeds to step S1105.
(Step S1105) The address issuing unit b113 selects an IP address within a predetermined address range, and generates IP address information of the selected new IP address. The address issuing unit b113 transmits the generated IP address information to the source media playback device a1. That is, a new IP address is paid out. Thereafter, the process ends.

<Regular IP address determination process>
Details of the formal IP address determination process in step S13 in FIG. 14 will be described below.
16 and 17 are flowcharts showing an example of the operation of the formal IP address determination process according to the present embodiment. The formal IP address determination process is a process performed by the formal address assignment unit C22 (FIG. 12) of the second DLNA connection device c2, and will be described with reference to FIG.

First, FIG. 16 will be described.
(Step S1301) The connection processing unit c221 receives a connection request from the first DLNA connection device c1. Thereafter, the process proceeds to step S1302.
(Step S1302) The network determination unit c222 determines whether the home network H1 is the same network as the home network H2. If it is determined that the home network H1 is the same network as the home network H2 (YES), the process proceeds to step S1303. On the other hand, if it is determined that the home network H1 is a different network from the home network H2 (NO), the process proceeds to step S1310.

(Step S1303) The address determination unit c223 determines whether there is a conflicting IP address between the provisional IP address of the home network H1 and the provisional IP address of the home network H2. If it is determined that there is a conflict between the provisional IP address of the home network H1 and the provisional IP address of the home network H2 (YES), the process proceeds to step S1304. On the other hand, if it is determined that there is no conflict between the provisional IP address of the home network H1 and the provisional IP address of the home network H2 (NO), the process proceeds to step S1309.

(Step S1304) The payout address search unit c224 determines whether or not the payable IP address of the same network address as that of the home network H2 can be paid out as the official IP address. If it is determined that the payable IP address of the same network address as that of the home network H2 can be paid as the official IP address (YES), the process proceeds to step S1308. On the other hand, if it is determined that the payable IP address of the same network address as that of the home network H2 cannot be paid as the official IP address (NO), the process proceeds to step S1305.

(Step S1305) The payout address search unit c224 determines whether or not two payable IP addresses having the same network address as the home network H2 can be paid out. If it is determined that two payable IP addresses with the same network address as the home network H2 can be paid out (YES), the process proceeds to step S1307. On the other hand, if it is determined that two or more payable IP addresses with the same network address as the home network H2 cannot be paid out (NO), the process proceeds to step S1306.

(Step S1306) The formal address determination unit c225 determines the connection mode as “different NW mode”. Thereafter, the process proceeds to step S1311 of FIG.
(Step S1307) The formal address determination unit c225 determines the connection mode as “temporary same NW mode”. Thereafter, the process proceeds to step S1312 of FIG.
(Step S1308) The formal address determination unit c225 determines the connection mode as “same NW mode”. Thereafter, the process proceeds to step S1313 in FIG.
(Step S1309) The formal address determination unit c225 determines the connection mode as “same NW mode”. Thereafter, the process proceeds to step S1314 in FIG.
(Step S1310) The formal address determination unit c225 determines the connection mode to be “different NW mode”. Thereafter, the process proceeds to step S1315.

Next, FIG. 17 will be described.
(Step S1311) The formal address determination unit c225 selects an IP address having a network address different from that of the home network H2, the number of provisional IP addresses included in the connection request. The formal address determination unit c225 determines the selected payable IP address as the formal IP address. Thereafter, the process proceeds to step S1316.
(Step S1312) The formal address determination unit c225 determines two payable IP addresses (payable IP addresses H2) of the same network address as the home network H2 as the formal IP addresses. Further, the formal address determination unit c225 selects an IP address having a network address different from that of the home network H2, as the number of provisional IP addresses included in the connection request. The formal address determination unit c225 determines the selected payable IP address as the formal IP address.
In step S1312, the number of official IP addresses is the number of provisional IP addresses plus two. As will be described later, the two payable IP addresses H2 are paid out to the temporary device c14 in FIG. 6 and the media playback device a1 that has transmitted the search message that triggered the connection request. Thereafter, the process proceeds to step S1316.

(Step S1313) The formal address determination unit c225 selects the payable IP address H2 as the number of provisional IP addresses included in the connection request. The formal address determination unit c225 determines the selected payable IP address as the formal IP address. Thereafter, the process proceeds to step S1316.
(Step S1314) The formal address determination unit c225 determines the provisional IP address included in the connection request as the formal IP address, and then proceeds to step S1316.
(Step S1315) The formal address determination unit c225 determines the provisional IP address included in the connection request as the formal IP address, and then proceeds to step S1316.

(Step S1316) The connection processing unit c221 generates a formal IP address response including the formal IP address determined in any of Steps S1311 to S1315, and transmits the response to the first DLNA connection device c1. Thereafter, the process proceeds to step S1317.

(Step S1316) The connection processing unit c221 determines whether or not the connection mode determined by the formal address determination unit c225 is the “same NW” mode. If it is determined that the mode is the “same NW” mode (YES), the process proceeds to step S1318. On the other hand, if it is determined that the mode is not the “same NW” mode (“different NW” mode or “same NW” mode) (NO), the process ends.
(Step S1317) The connection processing unit c221 registers the official IP address as a paid-out IP address in the DHCP server b2.

  18 and 19 are conceptual diagrams of formal IP address determination processing according to the present embodiment. In FIGS. 18 and 19, an ellipse denoted by reference numeral H1 represents the home network H1, and an ellipse denoted by reference numeral H2 represents the home network H2. A solid circle indicates a provisional IP address, and a broken circle indicates an IP address newly issued as an official IP address. In addition, circles hatched with diagonal lines indicate different IP addresses. In addition, circles hatched in a lattice shape indicate competing IP addresses.

  FIG. 18A is a diagram illustrating a case where the closed networks H1 and H2 are different networks. This figure shows that the home network H1 and the home network H2 hatched with a horizontal line have different network addresses. This figure shows a case where “NO” is determined in step S1302 in FIG. 16 and the process proceeds to step S1310. In this case, the temporary IP address becomes the official IP address without issuing a new IP address.

  FIG. 18B is a diagram showing a case where the closed networks H1 and H2 are the same network and the IP addresses do not conflict. This figure shows a case where “NO” is determined in step S1303 in FIG. 16 and the process proceeds to step S1309. In this case, the temporary IP address becomes the official IP address without issuing a new IP address.

FIG. 18C shows the case where the closed networks H1 and H2 are the same network, and when the IP addresses conflict, and the same number of IP addresses as the conflicting IP addresses and the same as the home network H2. It is a figure which shows when the IP address of a network can be paid out. This figure shows a case where “YES” is determined in step S1304 in FIG. 16 and the process proceeds to step S1308.
FIG. 18C shows that the IP addresses ADR1, ADR2, and ADR3 in the home network H1 are the same as the IP addresses ADR1, ADR2, and ADR3 in the home network H2, that is, the IP addresses are in conflict. It shows that. This figure shows that IP addresses ADR4 to 6 are newly issued in this case.

FIG. 19D shows the case where the closed networks H1 and H2 are the same network, and when the IP addresses conflict, and the same number of IP addresses as the conflicting IP addresses and the same as the home network H2. It is a figure which shows the case where the IP address of a network cannot be paid out, and the case where two IP addresses of the same network as the home network H2 can be paid out. This figure shows a case where “YES” is determined in step S1305 in FIG. 16 and the process proceeds to step S1307.
FIG. 19D shows that the IP addresses ADR1, ADR2, and ADR3 compete. This figure shows that IP addresses ADR4 to 9 are newly issued in this case. This figure also shows that two IP addresses ADR4 and 5 are IP addresses of the same network as the home network H2. This figure also shows that the four IP addresses ADR6 to 9 that are the same number as the provisional IP address are IP addresses of a network N3 different from the home network H2.

FIG. 19E shows the case where the closed networks H1 and H2 are the same network, and when the IP addresses conflict, and the same number of IP addresses as the conflicting IP addresses and the same as the home network H2. It is a figure which shows the case where the IP address of a network cannot be paid out, and the case where two IP addresses of the same network as the home network H2 cannot be paid out. This figure shows a case where “NO” is determined in step S1305 in FIG. 16 and the process proceeds to step S1306.
FIG. 19E shows that the IP addresses ADR1, ADR2, and ADR3 compete. This figure shows that IP addresses ADR4 to 7 are newly issued in this case. This figure also shows that the four IP addresses ADR4-7, which are the same number as the provisional IP address, are IP addresses of a network N3 different from the home network H2.

<Regular IP address determination process>
Details of the formal IP address setting process in step S14 in FIG. 14 will be described below.
FIG. 20 is a flowchart showing an example of the operation of the formal IP address setting process according to the present embodiment. The formal IP address setting process is a process performed by the formal address setting unit C13 (FIG. 8) of the first DLNA connection device c1, and will be described with reference to FIG.

(Step S1401) The connection processing unit c121 in FIG. 7 receives the formal IP address response from the second DLNA connection device c2, and outputs it to the address determination unit c131 in FIG. Thereafter, the process proceeds to step S1402.
(Step S1402) The address determination unit c131 determines whether or not the official IP address and the provisional IP address all match. If it is determined that the official IP address and the temporary IP address all match (YES), the process proceeds to step S1408. On the other hand, if at least one official IP address and provisional IP address do not match (NO), the process proceeds to step S1403.

(Step S1403) The network address determination unit c132 determines whether all the formal IP addresses are the IP addresses of the temporary IP addresses. If it is determined that all the formal IP addresses are IP addresses of the temporary IP addresses (YES), the process proceeds to step S1406. On the other hand, if it is determined that at least some of the formal IP addresses are not the IP addresses of the network addresses of the temporary IP addresses (NO), the process proceeds to step S1404.
(Step S1404) The network address determination unit c132 determines whether or not some of the formal IP addresses are the IP addresses of the temporary IP address network. When some of the formal IP addresses are the IP addresses of the temporary IP address network (YES), the process proceeds to step S142. On the other hand, if it is determined that all the formal IP addresses are not the IP addresses of the temporary IP address network (NO), the process proceeds to step S1405.

(Step S142) The reserved address information setting unit c133 performs a temporary same NW mode allocation process. The details of the temporary identical NW mode allocation process will be described later. Thereafter, the process ends.
(Step S1405) The reserved address information setting unit c133 determines that the formal IP address is arbitrarily assigned to the media playback device a1 having the temporary IP address so as not to overlap. Thereafter, the process proceeds to step S1409.
(Step S1406) The reserved address information setting unit c133 assigns the same formal IP address as the provisional IP address to the media playback device a1 having the provisional IP address included in the formal IP address. Thereafter, the process proceeds to step S1407.
(Step S1407) The reserved address information setting unit c133 determines the assignment of the remaining formal IP addresses to the media playback device a1 other than the media playback device a1 that has been assigned in Step S1407 so as not to overlap. To do. Thereafter, the process proceeds to step S1409.

(Step S1408) The reserved address information setting unit c133 assigns the same formal IP address as the provisional IP address to the media playback device a1 having the provisional IP address. Thereafter, the process proceeds to step S1409.
(Step S1409) The reserved address information setting unit c133 generates reserved address information indicating the assignment determined in steps S1405, S1407, and S1408, and registers it in the DHCP server b1. Thereafter, the process ends.

<About temporary same NW mode allocation processing>
Hereinafter, the temporary same NW mode allocation processing in step S142 in FIG. 20 will be described in detail.
FIG. 21 is a flowchart showing an example of the operation of the temporary identical NW mode allocation processing according to the present embodiment. The temporary identical NW mode allocation process is a process performed by the formal address setting unit C13 (FIG. 8) of the first DLNA connection apparatus c1, and will be described with reference to FIG.

(Step S1421) The reserved address information setting unit c133 extracts two formal IP addresses having the same network address as the provisional IP address, and selects one of them. Note that these two formal IP addresses are the formal IP addresses determined in step S1312 of FIG. 17, and are the IP addresses of the same network address as the home network H2.
The reserved address information setting unit c133 assigns the selected formal IP address to the media playback device (hereinafter referred to as media playback device A11) that has transmitted the search message that triggered the connection request. Thereafter, the process proceeds to step S1422.

(Step S1422) The reserved address information setting unit c133 selects a formal IP address different from the formal IP address selected in Step S1412, out of the two formal IP addresses extracted in Step S1421. The temporary device generation unit c135 generates a temporary device c14 having an official IP address selected by the reserved address information setting unit c133. Also, the temporary device generation unit c135 registers the formal IP address assigned in step S1421 and the device MAC address of the media playback device A11 in the temporary device c14. Then, it progresses to step S1423. That is, the reserved address information setting unit c133 determines the assignment of the IP address of the same network address as that of the home network H2 to the temporary device and the media playback device A11 in steps S1421 and S1422.
(Step S1423) The reserved address information setting unit c133 generates reserved address information indicating the assignment determined in steps S1421 and S1423, and registers it in the DHCP server b1. Thereafter, the process proceeds to step S1424.

(Step S1424) The reserved address information setting unit c133 extracts the device MAC address and IP address of the media playback device A11 from the payout address information input from the payout address information acquisition unit c111. Further, the reserved address information setting unit c133 reads the device MAC address and IP address of the media playback device A11 from the reserved address information stored in the reserved address information storage unit c134. The reserved address information setting unit c133 determines whether or not the correspondence between the extracted device MAC address and the IP address is the same as the correspondence between the read device MAC address and the IP address. That is, the reserved address information setting unit c133 determines whether or not the official IP address has been paid out to the media playback device A11.
If it is determined that the official IP address has been paid out (YES), the process proceeds to step S1425. In this case, the media playback device A11 communicates as a device on the same network as the media server a2 in the home network H2 via the temporary device. This communication is the same communication as in the “same NW” mode. On the other hand, if it is determined that the official IP address has not been paid out (NO), the process returns to step S1424.

(Step S1425) The reserved address information setting unit c133 determines assignment of a formal IP address to a device other than the media playback device A11. This formal IP address is the formal IP address determined in step S1312 of FIG. 17, and is an IP address of a network address different from the home network H2.
The reserved address information setting unit c133 generates reserved address information indicating the determined assignment and registers it in the DHCP server b1. Thereafter, the process proceeds to step S1426.
(Step S1426) The reserved address information setting unit c133 performs processing similar to that in Step S1424 for the device MAC address of the device other than the media playback device A11, thereby issuing a formal IP address to the device other than the media playback device A11. Determine if completed. If it is determined that the official IP address has been paid out (YES), the process proceeds to step S1427. On the other hand, when it is determined that the official IP address has not been paid out (NO), the process returns to step S1426.

(Step S1427) The reserved address information setting unit c133 determines assignment of the remaining formal IP address to the media playback device A11. The official IP address is an IP address having a network address different from that of the home network H2.
The reserved address information setting unit c133 generates reserved address information indicating the determined assignment and registers it in the DHCP server b1. Thereafter, the process proceeds to step S1428.

(Step S1428) The reserved address information setting unit c133 performs processing similar to that in Step S1425 on the device MAC address of the media playback device A11, thereby determining whether or not the official IP address has been paid out to the media playback device A11. judge.
If it is determined that the official IP address has been paid out (YES), the process ends. In this case, the media playback device A11 communicates as a device on a network different from the media server a2 in the home network H2. This communication is the same communication as in the “different NW” mode. In this case, the connection mode changing unit c122 in FIG. 7 changes the connection mode from the “temporarily identical NW” mode to the “different NW” mode.
On the other hand, if it is determined that the official IP address has not been paid out (NO), the process returns to step S1428.

  22 and 23 are conceptual diagrams of formal IP address setting processing according to the present embodiment. 22 and FIG. 23, the ellipses with reference signs S1 to S4 indicate formal IP addresses, and the ellipses with reference signs Z1 indicate temporary IP addresses. A hatched circle indicates an IP address, and a circle hatched with a vertical line indicates a formal IP address different from the provisional IP address. A circle (IP address) in the ellipse indicates that the network address is the same IP address. Note that FIGS. 22B and 23C show a case where the provisional IP address and the formal IP address are three different.

  FIG. 22A is a diagram illustrating a case where the official IP address matches the provisional IP address. This figure shows that the official IP address matches the provisional IP address. This figure shows a case where “YES” is determined in step S1402 in FIG. 20 and the process proceeds to step S1408. In this case, the same formal IP address as the provisional IP address is the same IP address, and each media playback device a1 continues to use the same IP address as it is.

  FIG. 22B is a diagram illustrating a case where the formal IP address and the provisional IP address do not match, and the formal IP address and the provisional IP address are the same network address. This figure shows that the formal IP addresses ADR4 to 6 are different from the temporary IP addresses. This figure shows a case where “YES” is determined in step S1403 in FIG. 20 and the process proceeds to step S1406. In this case, a change to a different IP address is performed by changing the media playback device a1 having a different temporary IP address and a formal IP address to a temporary IP address and a formal IP address.

FIG. 23C shows a case where the formal IP address does not match the provisional IP address, and when the formal IP address and the provisional IP address are different network addresses, and there is a formal IP address having the same network address as the provisional IP address. It is a figure which shows a case. This figure shows that the formal IP addresses ADR4 to 8 are different from the provisional IP address. This figure also shows that the formal IP addresses ADR4 and 5 are the same network addresses as the temporary IP addresses, and the formal IP addresses ADR6, 7, and 8 are network addresses different from the temporary IP addresses. This figure shows a case where “YES” is determined in step S1404 in FIG. 20 and the process proceeds to step S142.
In this case, one of the official IP addresses ADR4 and 5 is assigned to the temporary device c14, and the other is assigned to the media playback device A11. Further, the formal IP addresses ADR6 to 9 are assigned to devices other than the media playback device A11. Further, after the official IP address assigned to a device other than the media playback device A11 is issued, the remaining one of the official IP addresses ADR6 to ADR9 is assigned to the media playback device A11.

FIG. 23D shows a case where the formal IP address does not match the provisional IP address, and the formal IP address and the provisional IP address are different network addresses, and there is no formal IP address having the same network address as the provisional IP address. It is a figure which shows a case. This figure shows that the formal IP addresses ADR4 to ADR7 are different from the temporary IP address and are different network addresses from the temporary IP address. This figure shows a case where “NO” is determined in step S1404 in FIG. 20 and the process proceeds to step S1405.
In this case, the formal IP addresses ADR4 to 7 are assigned to the media playback device a1.

FIG. 24 is a conceptual diagram of temporary identical NW mode allocation processing according to the present embodiment. In FIG. 24, an ellipse with a reference H1 indicates the home network H1, and an ellipse with a reference H2 indicates the home network H2. The solid circle indicates an IP address. Further, the circles hatched with vertical lines indicate the IP addresses newly assigned as the official IP addresses. In addition, circles hatched in a lattice shape indicate competing IP addresses.
This figure shows processing performed when the formal IP address is determined as shown in (D) of FIG. 19 in the formal IP address determination processing.

FIGS. 24A and 24B are diagrams illustrating processing in steps S1421 to S1423 in FIG.
FIG. 24A shows that the temporary device c14 is generated and the official IP address ADR5 having the same network address as the temporary IP address is assigned. This figure also shows that the formal IP address ADR4 having the same network address as the provisional IP address is assigned to the media playback device A11.

FIG. 24B is a diagram showing processing in steps S1421 to S1423 in FIG. This figure shows that the temporary device c14 is connected to the home network H2 via the VPN. Further, the temporary device c14 and the media playback device A11 are connected, that is, the media playback device a1 is registered as a device on the same network as the temporary device.
Accordingly, the temporary device c14 can transmit the communication data transmitted from the home network H2 to the media playback device A11. Further, in the home network H1, only the temporary device c14 and the media playback device A11 are registered as devices in the same network as the home network H2, so that IP address conflicts can be prevented. For example, the premise IP addresses ADR2 and ADR3 in the home network H1 in FIG. 24 overlap with the IP addresses in the home network H2, but are not connected to the temporary device c14. Therefore, the temporary device c14 and the media playback device A11 are not connected. , And a network composed of devices in the home network H2, it is possible to prevent IP address conflicts.

FIG. 24C is a diagram illustrating processing in step S1425. This figure shows that formal IP addresses ADR6 to 8 of a network address different from the provisional IP address are assigned to devices other than the media playback device A11.
FIG. 24D is a diagram illustrating the processing in step S1427. This figure shows that a formal IP address ADR9 having a network address different from the provisional IP address is assigned to the media playback device A11. This figure also shows that the temporary device c14 has been deleted.

<About payout address information>
Hereinafter, the formal IP address paid out by the formal IP address setting process will be described using the payout address information (FIGS. 25 to 28) stored in the payout address information storage unit b115. In this description, the payout address information of the temporary IP address before the connection process is the payout address information shown in FIG.

FIG. 25 is a schematic diagram illustrating an example of a payout address table according to the present embodiment. This figure shows a case where the official IP address assigned in steps S1406 and S1407 in FIG. 20 has been issued.
When the payout address information on the first line in FIG. 25 and the payout address information on the first line in FIG. 5 are compared, the correspondence between the device Mac address and the private IP address is the same. In other words, the payout address information on the first line in FIG. 25 indicates that the same official IP address (192.168.1.1) as the temporary IP address has been paid out to the media playback device A11 with the device MAC address “MAC_A11”. Indicates. The payout address information indicates that the lease period of the official IP address is “4320 minutes” and is longer than the lease period “60 minutes” of the provisional IP address.

On the other hand, when the payout address information on the 2nd to 4th lines in FIG. 25 and the payout address information on the 2nd to 4th lines in FIG. 5 are compared, the correspondence between the device Mac address and the private IP address is different. For example, the payout address information on the second line in FIG. 25 is sent to the media playback device A12 with the device MAC address “MAC_A12” and a formal IP address (192.168.8.1) different from the provisional IP address (192.168.1.2). .5) indicates that it has been paid out.
The network addresses of the private IP addresses in FIG. 25 are all “192.168.1.0”, which is the same as the network address of the provisional IP address.

  26 to 28 are schematic diagrams illustrating another example of the payout address table according to the present embodiment. This figure shows a case where the official IP address assigned in step S142 in FIG. 20 has been issued. In this case, since the formal IP address is assigned in the temporary same NW mode assignment process (FIG. 21), FIGS. 26 to 28 will be described with reference to FIG.

FIG. 26 shows the payout address information when it is determined “YES” in step 1424 of FIG.
The payout address information in the first to third lines in FIG. 26 is the same as the payout address information in the second to fourth lines in FIG. That is, the payout address information on the first to third lines in FIG. 26 is the payout address information of the temporary IP address.
The payout address information on the fourth line in FIG. 26 indicates the payout address information paid out to the temporary device c14. This payout address information indicates that the private IP address “PA_V10” (192.168.1.6) is registered in the network interface card of the device MAC address “MAC_C1”. This private IP address is “192.168.1.0”, which is the same as the network address of the temporary IP address.

 In addition, the payout address information on the fifth line in FIG. 26 indicates that the media playback device A11 with the device MAC address “MAC_A11” has an official IP address (192.168.8.1) different from the provisional IP address (192.168.1.1). .5) indicates that it has been paid out. This private IP address is “192.168.1.0”, which is the same as the network address of the temporary IP address. The payout address information indicates that the lease period is shorter than the lease period of the official IP address in the case of another connection mode. As a result, in the “temporarily same NW” mode, the media playback device A11 can transmit an address issue request in a shorter period than the lease period of the official IP address in the other connection modes.

FIG. 27 shows the payout address information when it is determined “YES” in step 1426 of FIG.
When the payout address information on the 3rd to 5th lines in FIG. 27 is compared with the payout address information on the 2nd to 4th lines in FIG. 5, the correspondence between the device Mac address and the private IP address is different. For example, the payout address information on the second line in FIG. 27 indicates that the media playback device A12 with the device MAC address “MAC_A12” has an official IP address (192.168.8.2) different from the provisional IP address (192.168.1.2). .2) indicates that it has been paid out. The official IP address is “192.168.2.0”, which is a network address different from the network address of the provisional IP address.

FIG. 28 shows payout address information when it is determined “YES” in step 1428 of FIG.
When the payout address information on the fourth line in FIG. 28 is compared with the payout address information on the second line in FIG. 27, the correspondence between the device Mac address and the private IP address is different. The payout address information on the fourth line in FIG. 28 is sent to the media playback device A11 with the device MAC address “MAC_A11”, and an official IP address (192.168.168) different from the official IP address (192.168.1.5) in FIG. .2.4) indicates that it has been paid out. The official IP address is “192.168.2.0”, which is a network address different from the network address of the official IP address in FIG.

<About VPN connection processing>
Details of the VPN connection process in step S15 in FIG. 14 will be described below.
FIG. 29 is a flowchart showing an example of the operation of the VPN connection processing according to the present embodiment. This formal IP address setting process is a process performed by the VPN setting unit c137 (FIG. 8) and the communication data conversion unit c15 of the first DLNA connection apparatus c1, and will be described with reference to FIG.

(Step S1501) The VPN setting unit c137 in FIG. 8 releases a communication port necessary for VPN connection. Further, the VPN setting unit c137 performs port forwarding setting for assigning a communication destination for each port number of the released communication port. Thereafter, the process proceeds to step S1502.
(Step S1502) The VPN setting unit c137 determines whether or not the connection mode is the “different NW” mode. If it is determined that the mode is “different NW” (YES), the process proceeds to step S1509. On the other hand, if it is not the “different NW” mode, that is, the “same NW” mode or the “temporary same NW” mode (NO), the process proceeds to step S1503.

(Step S1503) The VPN setting unit c137 performs TAP-ETH bridge setting. Thereafter, the process proceeds to step S1504.
(Step S1504) The VPN setting unit c137 performs the layer 2-VPN connection according to the setting performed in step S1503. Thereafter, the process proceeds to step S1505.
(Step S1505) The VPN setting unit c137 determines whether or not the connection mode is the “temporarily identical NW” mode. If it is determined that the mode is the “temporarily identical NW” mode (YES), the process proceeds to step S1506. In this case, the formal address setting unit C13 performs a temporary identical NW mode allocation process shown in FIG. On the other hand, when the mode is not the “temporary same NW” mode, that is, the mode is the “same NW” mode (NO), the process is terminated.

(Step S1506) The VPN setting unit c137 determines whether or not the temporary same NW mode allocation process of the formal address setting unit C13 is completed. That is, the VPN setting unit c137 determines whether or not the delivery of the official IP address of the network address different from the temporary IP address is completed. If it is determined that the payout has been completed (YES), the process proceeds to step S1507. On the other hand, if it is determined that the payout has not been completed (NO), the process returns to step S1506.
(Step S1507) The VPN setting unit c137 stops the layer 2-VPN connection. Thereafter, the process proceeds to step S1508.
(Step S1508) The VPN setting unit c137 deletes the temporary device c14. Thereafter, the process proceeds to step S1509.

(Step S1509) The VPN setting unit c137 performs layer 3-VPN connection. Thereafter, the process proceeds to step S18.
(Step S18) The TTL extension processing unit c155 in FIG. 9 performs a TTL extension process. Details of the TTL extension processing will be described later. Thereafter, the process proceeds to step S1510.
(Step S1510) The routing method converter c154 in FIG. 9 performs an inverse NAT conversion process based on the inverse NAT conversion information, as will be described later. Thereafter, the process ends.

<About multicast routing processing>
Hereinafter, details of the multicast routing process performed by the routing method conversion unit c154 of the second DLNA connection device c2 will be described. First, NAT information (FIG. 30) and inverse NAT conversion information (FIG. 31) will be described, and then header information (FIG. 32) of the communication packet will be described.

FIG. 30 is a schematic diagram illustrating an example of a NAT table according to the present embodiment. As shown in the figure, the NAT table has columns of items of IP address 1, port number 1, IP address 2, and port number 2. The NAT table stores NAT information for each IP address 1.
For example, the NAT information on the first line in FIG. 30 indicates the NAT information of the media server A21 in FIG. This NAT information includes an association for converting IP address 1 “GA_C2” and port number 1 “n1” into IP address 2 “PA_A21” (for example, 192.168.1.2) and port number 2 “s1”. Show.

FIG. 31 is a schematic diagram illustrating an example of an inverse NAT conversion table according to the present embodiment. As shown in the figure, the reverse NAT conversion table has columns of items of IP address 1, port number 1, IP address 2, and port number 2. The reverse NAT conversion table stores reverse NAT conversion information for each IP address 1.
For example, the reverse NAT conversion information on the first line in FIG. 31 indicates the reverse NAT conversion information of the media playback device A11 in FIG. This inverse NAT conversion information corresponds to converting IP address 1 “GA_C1” and port number 1 “m1” into IP address 2 “VPA_A21” (for example, 192.168.1.3) and port number 2 “t1”. Indicates the date. Here, “VPA_A21” is a virtual IP address of the network address of the home network H2, and is an IP address assigned by the communication data conversion setting unit c232 in FIG.

  FIG. 32 is a schematic diagram showing header information of a communication packet according to the present embodiment. This figure shows header information of a communication packet transmitted from the media playback device A11 (private IP address “A11” and port number “p1”) to the media server (private IP address “A11” and port number “p1”). . Moreover, the example of the conversion of the header information of the communication packet shown in this figure is an example performed based on the NAT information of the example of FIG. 30 and the inverse NAT conversion information of the example of FIG.

  In FIG. 32, header information P11 denoted by reference numeral P11 indicates header information obtained by converting destination information and transmission source information of the communication packet transmitted from the media playback device A11 in the first DLNA connection device A1. This figure shows that the destination information of the header information P11 is the IP address “GA_C2” and the port number “n1”. This figure also shows that the transmission source information of the header information P11 is the IP address “GA_C1” and the port number “m1”.

  In FIG. 32, header information P12 denoted by reference sign P12 indicates header information obtained by converting the destination information and the transmission source information from the header information P11 in the second DLNA connection apparatus C1. This figure shows that the destination information of the header information P12 is the IP address “PA_A21” and the port number “s1”. This figure also shows that the transmission source information of the header information P11 is the IP address “VPA_A11” and the port number “t1”. Here, the destination information of the header information P11 is NAT-converted to the destination information of the header information P22 by the NAT information of FIG.

  Further, the transmission source information of the header information P11 is inversely NAT converted to the transmission source information of the header information P12 (information surrounded by a broken line with a reference symbol P121) by the inverse NAT conversion information of FIG. The IP address of the source information after the conversion is a virtual IP address of the network address of the home network H2. As described above, by this conversion, even a device that receives only a communication packet from a device in the home network H2 can receive a communication packet from a device in the home network H1.

<About TTL extension processing>
The details of the TTL extension processing in step S18 in FIG. 29 will be described below.
FIG. 33 is a flowchart showing an example of the operation of the TTL extension processing according to the present embodiment. This TTL extension process is a process performed by the TTL extension processing unit c155 in FIG.

(Step S1801) The TTL extension processing unit c155 receives the search message via the routing method conversion unit c154. Thereafter, the process proceeds to step S1802.
(Step S1802) The TTL extension processing unit c155 reads search message reception information from a storage unit (not shown). The search message reception information is information including the device MAC address of the search message transmission source, the number of times the search message has been received, and the number of times the search message has been received most recently. Also, the TTL extension processing unit c155 extracts the device MAC address included in the search message. If there is no search message reception information for the extracted device MAC address, or if the number of receptions of the search message reception information for the extracted device MAC address is “0” (YES), the TTL extension processing unit c155 proceeds to step S1808. move on. On the other hand, if the number of receptions of the search message reception information of the extracted device MAC address is one or more, the process proceeds to step S1803.

(Step S1803) The TTL extension processing unit c155 determines whether or not a predetermined time has elapsed from the reception time of the search message reception information for the device MAC address extracted in step S1802. If it is determined that the predetermined time has elapsed (YES), the process proceeds to step S1808. On the other hand, if it is determined that the predetermined time has not elapsed (NO), the process proceeds to step S1804.
(Step S1804) The TTL extension processing unit c155 determines whether or not the number of reception times of the search message reception information for the device MAC address extracted in Step S1802 is larger than a predetermined specified value. If it is determined that the value is larger than the specified value (YES), the process proceeds to step S1806. On the other hand, when it determines with the following from a regulation value (NO), it progresses to step S1805.

(Step S 1805) The TTL extension processing unit c 155 updates the search message reception information reception count to a value increased by one. Thereafter, the process proceeds to step S1807.
(Step S1806) The TTL extension processing unit c155 updates the number of times the search message reception information is received to “0”. Thereafter, the process proceeds to step S1807.
(Step S1807) The TTL extension processing unit c155 updates the reception time of the search message reception information with the current time. Thereafter, the process ends.

(Step S1808) The TTL extension processing unit c155 extends the TTL of the search message. Thereafter, the process proceeds to step S1809.
(Step S1809) The TTL extension processing unit c155 updates the reception count of the search message reception information to a value increased by one. Thereafter, the process proceeds to step S1810.
(Step S1810) The routing method converter c154 transmits a search message to the second DLNA connection device c2.

The details of the search message will be described below.
FIG. 34 is a flowchart showing an example of search message communication according to the present embodiment. This figure is a diagram showing communication of search messages in the case of the same segment method.

(Step S201) The first DLNA connection device c1 performs TAP-ETH bridge setting. Thereafter, the process proceeds to step S202.
(Step S202) The second DLNA connection device c2 performs TAP-ETH bridge setting. Thereafter, the process proceeds to step S203.
(Step S203) The first DLNA connection device c1 and the DLNA connection device c2 of the younger brother 2 perform VPN connection. Thereafter, the process proceeds to step S204.

(Step S204) The media playback device a1 transmits a search message. This search message is transmitted from the first DLNA connection device c1 to the DLNA connection device c2 of the younger brother 2 through the VPN tunnel generated by the VPN connection in step S203. The brother 2 DLNA connection device c2 multicasts the received search message to the LAN L2. Thereafter, the process proceeds to step S205.
(Step S205) The media server a2 receives the search message transmitted in step S204. The media server a2 generates a response message for the received search message and addressed to the media playback device a1. The media server a2 transmits the generated response message. This response message is unicast to the media playback device a1 via the younger brother's DLNA connection device c2, the VPN tunnel, and the first DLNA connection device c1.
Thereafter, the media playback device a1 and the media server a2 similarly perform communication via the VPN tunnel.

  FIG. 35 is a flowchart showing another example of search message communication according to the present embodiment. This figure is a diagram showing search message communication in the case of the multicast routing method.

(Step S211) The first DLNA connection apparatus c1 and the DLNA connection apparatus c2 of the second brother perform VPN connection. Thereafter, the process proceeds to step S212.
(Step S212) The media playback device a1 transmits a search message. Thereafter, the process proceeds to step S18.
(Step S18) The first DLNA connection device c1 performs TTL extension processing. The search message in which the TTL extension has been performed in the TTL extension process is transmitted to the DLNA connection device c2 of the younger brother 2 through the VPN tunnel generated by the VPN connection in step S211. The younger brother's DLNA connection device c2 performs reverse NAT conversion on the received search message and multicasts it to the LAN L2. Thereafter, the process proceeds to step S213.
(Step S213) The media server a2 receives the search message transmitted in step S18. The media server a2 generates a response message for the received search message and addressed to the media playback device a1. The media server a2 transmits the generated response message. This response message is unicast to the media playback device a1 via the younger brother's DLNA connection device c2, the VPN tunnel, and the first DLNA connection device c1.
Thereafter, the media playback device a1 and the media server a2 similarly perform communication via the VPN tunnel.

<About used formal IP address notification processing and used formal IP address collection processing>
Details of the used formal IP address notification process in step S16 and the used formal IP address collection process in step S17 will be described below.
FIG. 36 is a flowchart showing an example of operations of a used formal IP address notification process and a used formal IP address collection process according to the present embodiment.

(Step S161) The first DLNA connection apparatus c1 uses a formal IP address whose lease period has passed (lease period expired) or a formal IP address whose allocation has been completed (released) (these formal IP addresses have been used) It is determined whether or not there is an official IP address. Note that the case where the assignment is terminated is, for example, a case where the media playback device a1 to which the official IP address has been assigned is removed from the LAN L1. If it is determined that there is a used official IP address (YES), the process proceeds to step S162. On the other hand, when it is determined that there is no used official IP address (NO), the process returns to step S161.
(Step S162) The first DLNA connection device c1 transmits a used formal IP address notification including the used formal IP address. Thereafter, the process proceeds to step S171.

(Step S171) The second DLNA connection device c2 receives the used formal IP address notification. Thereafter, the process proceeds to step S172.
(Step S172) The second DLNA connection device c2 extracts the used formal IP address from the used formal IP address notification. The second DLNA connection device c2 deletes the extracted used formal IP address from the formal address storage unit c227. Thereafter, the process ends.

  As described above, according to the present embodiment, the network determination unit c222 of the second DLNA connection device c2 uses the network address of the temporary IP address in the home network H1 and the network address of the private IP address in the home network H2. , Are the same network address. If the address determination unit c223 determines that the network determination unit c222 has the same network address, the network address of the temporary IP address in the home network H1 and the network address of the private IP address in the home network H2 It is determined whether there is the same IP address. The VPN setting unit c137 selects the connection method between the home networks H1 and H2 based on the determination result (connection mode) of the network determination unit c222 and the address determination unit c223, and the media playback device a1 and the media server a2 To enable communication. As a result, the communication system can connect the home networks H1 and H2 by selecting a connection method, regardless of whether the home networks H1 and H2 are assigned the same network address or different networks. The playback device a1 and the media server a2 can communicate quickly and accurately.

  Further, according to the present embodiment, in the communication system, when the address determination unit c223 determines that there is the same IP address, the payout address search unit c224 uses the payable IP address H2 as the official IP address, and the media playback device It is determined whether or not all of a1 can be paid out, and a connection method is selected based on the determination result. Thereby, for example, when the communication system can pay out to all of the media playback devices a1, the payable IP address H2 is assigned to the media playback device a1, and the home networks H1 and H2 are connected as the same network. be able to. In addition, when the communication system cannot pay out to all of the media playback devices a1, an IP address of a network address other than the network address of the home network H2 is assigned to the media playback device a1, and the home networks H1 and H2 are different. Can be connected as a network. Therefore, in the communication system, the media playback device a1 and the media server a2 can communicate quickly and accurately.

  Further, according to the present embodiment, in the communication system, when the payout address search unit c224 determines that the payable IP address H2 cannot be paid out to all of the media playback devices a1, the media playback that transmitted the search message. The connection method between the device A11 and the media server a2 can be communicated by the same segment method, and then the connection method between all the media playback devices a1 and the media server a2 is changed to the multicast routing method. As a result, the communication system can connect the media playback device A11 that has transmitted the search message to the home network H2 with priority over the other media playback device a1, and communicate the previous media playback device A11 more quickly. Can be possible.

Further, according to the present embodiment, in the communication system, the formal address setting unit C13 assigns one formal IP address of the same network address as the home network H2 to the temporary device c14, and assigns another formal IP address to the temporary device c14. Assigned to the media playback device A11. The temporary device generation unit c135 connects the temporary device c14 and the media playback device A11. Thereby, the communication system can connect the temporary device and the media playback device A11 as a device of the same network as the home network H2. Further, it is possible to prevent duplication of the temporary IP address assigned to the media playback device a1 other than the media playback device A11 and the private IP address assigned to the media server a2.
Further, according to the present embodiment, since the TTL extension processing unit c155 increases the TTL of the communication data in the communication system, the number of router devices when the media playback device a1 and the media server a2 can communicate with each other is increased. Even if it increases, the communication data transmitted by the media playback device a1 can be relayed and reliably received by the media server a2.

  In the above embodiment, the formal address issuing unit C22 has the configuration of the second DLNA connection device c2. However, the present invention is not limited to this, and the first DLNA connection device c1 may be provided. In this case, the first DLNA connection device c1 receives the provisional IP address information of the home network H2 from the second DLNA connection device c2, and performs formal IP address determination processing.

  In the above embodiment, the case where the first DLNA connection device c1 and the second DLNA connection device c2 are DLNA devices has been described. However, the present invention is not limited to this, and even a device such as a server may be used. Good. The media playback device a1 and the media server a2 may be computers such as PCs. The home network may be a computer network such as a LAN. INDUSTRIAL APPLICABILITY The present invention is suitable for communication for discovering and controlling a network device using a multicast packet and a unicast packet in a local network and realizing an application. Communication is possible via a network (WAN).

  Further, according to the present embodiment, the TTL extension processing unit c155 determines whether or not to extend the TTL based on the number of receptions and the reception time, so that the number of search messages with the TTL extended can be controlled. , It is possible to prevent an increase in network load due to a search message having a long TTL.

  Note that a part of the media playback device a1, the DHCP server b1, the first DLNA connection device c1, and the second DLNA device d1 in the above-described embodiment may be realized by a computer. In that case, the program for realizing the control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by a computer system and executed. The “computer system” herein is a computer system built in the media playback device a1, the DHCP server b1, the first DLNA connection device c1, or the second DLNA device d1, and includes an OS and peripheral devices. Etc. hardware is included. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” is a medium that dynamically holds a program for a short time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, In such a case, a volatile memory inside a computer system serving as a server or a client may be included and a program that holds a program for a certain period of time. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the present invention. It is possible to

  a111 ... address update unit, a112 ... address information storage unit, a113 ... media server detection unit, a114 ... media server information storage unit, b111 ... reserved address information acquisition unit, b112 ... Reserved address information storage unit, b113... Address issue unit, b114... Lease period setting unit, b115 ... issue address information storage unit, b116 ... issue address information notification unit, c111 ... issue address acquisition Part, c112 ... payout address information storage part, c12 ... network connection processing part, c124 ... formal address storage part, c125 ... provisional address storage part, c13 ... connection setting part, c14. Temporary device, c15 ... communication data conversion unit, c121 ... connection processing unit, c131 ... address determination unit, c 23 ... Connection mode storage unit, c131 ... Address determination unit, c132 ... Network address determination unit, c133 ... Reserved address information setting unit, c134 ... Reserved address information storage unit, c135 ... Temporary device generation unit (temporary same network generation unit), c151 ... conversion method selection unit, c152 ... reverse NAT conversion information storage unit, c153 ... NAT information storage unit, c154 ... routing method conversion unit, c155 ... TTL extension processing unit, c156 ... Same segment method conversion unit, a214 ... Access control unit, a213 ... Search message response unit, c22 ... Network connection processing unit, c23 ... Connection Setting unit, c221 ... connection processing unit, c222 ... network determination unit, c223 ... address determination unit c224 ... payout address search unit, c225 ... formal address determination unit, c226 ... connection mode storage unit, c227 ... formal address storage unit, c231 ... router setting unit, c232 ... communication data Conversion setting section

Claims (7)

Assigned to the first communication management device that manages the first communication address assigned to the first communication device connected to the first communication network, and to the second communication device connected to the second communication network A communication system comprising: a second communication management device that manages a second communication address;
The first communication management device or the second communication management device is:
A network determination unit that determines whether the network identification information indicated by the first communication address and the network identification information indicated by the second communication address are the same network identification information;
An address determination unit that determines whether or not the first communication address and the second communication address have the same communication address when the network determination unit determines that the network identification information is the same;
It is determined whether the same network address that is a communication address different from the second communication address and is a communication address of network identification information indicated by the second communication address can be assigned to the first communication device. A payout address search unit,
A connection setting unit that selects a connection method that enables communication between the first communication device and the second communication device, based on determination results of the network determination unit, the address determination unit, and the payout address search unit; ,
A communication system comprising: A plurality of the first communication devices;
The payout address search unit
The communication system according to claim 1, wherein it is determined whether or not the same network address can be assigned to all of the first communication devices. The first communication device is a communication device that performs multicast to a connected network and detects a communication device of a communication destination by a response thereof,
The connection setting unit, when the payout address search unit determines that the same network address cannot be assigned to all of the first communication devices, and the first communication device that has performed the multicast and the second communication Select the first connection method that enables communication as a device in the same network as the connection method with the device,
After enabling the first communication device that has performed the multicast to communicate using the first connection method, the connection method between all of the first communication devices and the second communication device is communicated as a different network. The communication system according to claim 2, further comprising a connection method change unit that changes to a second connection method that enables the connection method. The first communication management device or the second communication management device is:
If the payout address search unit determines that the same network address cannot be assigned to all of the first communication devices, the payout address search unit includes an address determination unit that pays out the two same network addresses,
The first communication management device includes:
It is determined that one of the same network addresses issued by the address determination unit is assigned to a connection device that can communicate with the second communication device, and the other network same address is assigned to the first network that has performed the multicast. A formal address setting unit that decides to be assigned to the communication device;
A temporary same network generation unit that registers the connection device and the first communication device that has performed the multicast as a device of a network indicated by the same network address;
The communication system according to claim 3, further comprising: In the first communication management device that manages the first communication address assigned to the first communication device connected to the first communication network,
The network identification information indicated by the first communication address and the network identification information indicated by the second communication address assigned to the second communication device connected to the second communication network are the same network identification information. A network determination unit for determining whether or not
An address determination unit that determines whether or not the first communication address and the second communication address have the same communication address when the network determination unit determines that the network identification information is the same;
It is determined whether the same network address that is a communication address different from the second communication address and is a communication address of network identification information indicated by the second communication address can be assigned to the first communication device. A payout address search unit,
A connection setting unit that selects a connection method that enables communication between the first communication device and the second communication device, based on determination results of the network determination unit, the address determination unit, and the payout address search unit; ,
A first communication management device comprising: In the communication management method in the first communication management device for managing the first communication address assigned to the first communication device connected to the first communication network,
The first communication management device has network identification information indicated by the first communication address, and network identification information indicated by a second communication address assigned to a second communication device connected to a second communication network. , Are the same network identification information, a first process of determining whether or not,
If the first communication management apparatus determines that the same network identification information is obtained in the first process, whether or not the first communication address and the second communication address have the same communication address A second process of determining
It is determined whether the same network address that is a communication address different from the second communication address and is a communication address of network identification information indicated by the second communication address can be assigned to the first communication device. A third process to
A connection method that enables communication between the first communication device and the second communication device is selected based on the determination results of the first step, the second step, and the third step. And the process
A communication management method characterized by comprising: A computer of a first communication management device for managing a first communication address assigned to a first communication device connected to a first communication network;
The network identification information indicated by the first communication address and the network identification information indicated by the second communication address assigned to the second communication device connected to the second communication network are the same network identification information. Network determination means for determining whether or not
An address determination means for determining whether or not the first communication address and the second communication address have the same communication address when the network determination means determines that the network identification information is the same;
It is determined whether the same network address that is a communication address different from the second communication address and is a communication address of network identification information indicated by the second communication address can be assigned to the first communication device. A payout address search means,
A connection setting means for selecting a connection method enabling communication between the first communication apparatus and the second communication apparatus based on determination results of the network determination means, the address determination means, and the payout address search means;
Communication management program to function as.

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