JP2005323347A - Communication apparatus, method and program for realizing p2p communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication apparatus which can establish P2P communication even in a communication environment where a network is intricately constituted. <P>SOLUTION: A communication apparatus includes a global address information acquiring section 101; an NAT setting request section 102; a WAN-side address information acquiring section 103; a local address information acquiring section 104; an address information notification section 105 for notifying first global address information, first WAN-side address information, and first local address information acquired to a communication partner; and an address information acquiring section 106 for acquiring second global address information, second WAN-side address information, and second local address information assigned to the communication partner. The communication apparatus of the invention determines a method by which P2P connection can be established based on the first and the second global address information, the first and the second WAN-side address information, and the first and the second local address information. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication apparatus, method, and program used in a communication network, and more specifically, a communication apparatus, method, and program for realizing peer-to-peer communication (hereinafter referred to as P2P communication). About.

  NAT (Network Address Translation: NAT based on address translation rules) is a concept that includes Network Address Port Translation (NAPT) as a technology that enables a plurality of user terminals in the home to connect to the Internet using a single global address. ) Technology is used. In the NAT technology, when a message is routed from a LAN (Local Area Network) side to a WAN (Wide Area Network) side, the router converts source address information to WAN side address information. When routing from the WAN side to the LAN side, the router converts the destination address information from the WAN side address information to the LAN side address information according to an address conversion rule, that is, a NAT conversion table.

However, in the network environment using the NAT technology, the following conditions (1) and (2) are necessary for P2P communication with the other user terminal.
(1) A router address conversion rule on a communication path between user terminals that perform P2P communication is appropriately set.
(2) Appropriate access destination address information of the P2P communication partner is obtained.

  The appropriate access destination address information (2) is global address information (IP address, port number) when the user terminals are connected by a network using a global address such as the Internet. This global address information is, for example, the WAN address and port number of the address translation rule set in the router connected to the Internet among the address translation rules set in the router between the user terminal and the Internet. .

  On the other hand, when the user terminals are connected by a router in the private network, the address information of the access destination needs to be the address information of the segment that is commonly connected between the user terminals. For example, the LAN side segment of the router 2A is a common segment in the user terminal 1a and the user terminal 1b in FIG. Further, in the user terminal 1a and the user terminal 1c or 1d, the LAN side segment of the router 2C is a common segment.

  Thus, when the user terminals are connected by the router in the private network, appropriate access destination address information varies depending on the communication destination user terminal. The specific address information may be address information of a communication partner or a WAN address and a port number of an address conversion rule set in a router to which the communication partner is connected.

  It is not guaranteed that these conditions are always met. Therefore, in general, P2P communication is very difficult.

  As a technology that satisfies the above conditions (1) and (2) under the limited conditions in which user terminals are connected via the Internet and only one router exists between the user terminals and the Internet, In particular, there is known a method using UPnP Internet Gateway Device (IGD) Device Control Protocol (hereinafter referred to as UPnP / IGD) for setting the NAT conversion table of the upper router.

Also, a method has been proposed in which a communicator set for NAT traversal is installed in each network, and each user terminal communicates via the communicator (see, for example, Patent Document 1). .
JP 2003-87288 A (page 2 to page 4, FIG. 1)

  In the conventional method using UPnP / IGD, a method in which a user terminal sets a NAT conversion table for an upper router and a method in which the user terminal acquires a WAN address of the upper router are proposed. However, P2P communication cannot be realized in a complicated network with only UPnP • IGD.

  Also, with the method proposed in Patent Document 1, P2P communication cannot be realized when the network between user terminals changes dynamically.

  Therefore, an object of the present invention is to provide a communication apparatus, method, and program capable of realizing P2P communication even in a communication environment in which a network is configured in a complicated manner. A further object of the present invention is to provide a communication device, method, and program capable of realizing P2P communication even when the network configuration changes dynamically.

  In order to solve the above problems, the present invention has the following features. The present invention is a communication device that can be connected to a network equipped with the Internet, and communicates with a server on the network to acquire information relating to an address on the Internet assigned to the device as first global address information. A global address information acquisition unit that acquires information on an address on the WAN side that is assigned to a router that is directly above the local device, WAN side address information acquisition unit that acquires, as the first WAN side address information, Via a server on the network, a local address information acquisition unit that acquires information on an address on the assigned local network as first local address information, and a communication device of a communication partner who desires P2P communication , First global address information, first The address information notifying means for notifying the WAN address information and the first local address information, and the second information which is information on the Internet address assigned to the communication device of the communication partner via the server on the network Global address information, second WAN-side address information that is information related to the WAN-side address assigned to the router that exists immediately above the communication device of the communication partner, and the local network assigned to the communication device of the communication partner Address information acquisition means for acquiring second local address information, which is information related to addresses in the network, and P2P communication is performed based on the first and second global address information, WAN address information, and local address information. Determine possible methods.

  According to the present invention, even if the network is configured in a complicated manner, communication devices that desire P2P communication can obtain global address information, WAN-side address information, and local address information. The communication device determines a method capable of P2P communication based on the first and second global address information, WAN side address information, and local address information. Therefore, a communication apparatus capable of realizing P2P communication is provided even in a communication environment in which a network is configured in a complicated manner. Even if the network configuration is dynamically changed, the global address information, the WAN address information, and the local address information can be newly acquired according to the change. Therefore, a communication device capable of realizing P2P communication even when the network configuration changes dynamically is provided.

  Preferably, further comprising a NAT setting request means for setting an address translation rule for the router immediately above the own device, the WAN side address information acquisition means is based on the address translation rule set in the router, The first WAN address information assigned to the own device may be acquired.

  Preferably, the NAT setting requesting unit further includes a NAT setting determining unit for determining whether or not to set an address conversion rule. If the NAT setting determining unit does not determine that the address conversion rule should be set, the NAT setting determining unit It is preferable to determine a method capable of P2P communication without causing the requesting means to set an address conversion rule.

  As a result, unnecessary NAT setting is not performed, so that improvement of security and high speed of processing can be expected.

  Preferably, the present invention further uses any one of the second global address information, the second WAN side address information, and the second local address information acquired by the address information acquisition unit. The use address information determination means for determining whether or not to start P2P communication with the communication partner of the communication partner and the use address information determination means are determined to start P2P communication using any one address information. In this case, a P2P communication processing unit that starts P2P communication with the communication apparatus of the communication partner using the address information is provided.

  Accordingly, the communication device can start P2P communication using any one of the global address information, the WAN address information, and the local address information.

  Preferably, the used address information determination means transmits a P2P connection request with one of the second global address information, the second WAN address information, and the second local address information as a destination. When a response is returned from the communication device of the communication partner, it may be determined that the P2P communication is started using the address information used as the destination.

  As a result, a P2P connection request using the global address information, WAN address information, and local address information is tried. As a result of the P2P connection request being tested, a response from the communication partner is returned, which means that P2P communication is possible using the address information used when the P2P connection request is tried. Therefore, in such a case, the communication apparatus can start P2P communication using the address information.

  Preferably, when the P2P connection request from the communication apparatus of the communication partner is received, the use address information determination unit determines to start P2P communication using the source address information of the P2P connection request, and the P2P communication processing unit If it is determined by the used address information determining means that the P2P communication is started using the source address information, the source address information is used to start the P2P communication with the communication partner communication device.

  As a result, the communication device can perform P2P communication with the communication partner in such a manner that the source address of the P2P connection request from the communication partner is traced in reverse. Therefore, even if the P2P connection cannot be established using the address information of the communication partner, the communication device can perform P2P communication using the source address information of the P2P connection request from the communication partner.

  Preferably, when the P2P communication is not determined to be started by using any one address information by the used address information determination unit and it is not determined to start the P2P communication using the source address information, the P2P communication is performed. The processing means may determine to start P2P communication using a P2P communication system or STUN communication system via a server.

  Thus, P2P communication is enabled by switching the P2P communication method. Therefore, it is expected that P2P communication will be possible no matter how complicated the network configuration is.

  Preferably, the used address information determination unit determines whether or not the first global IP address included in the first global address information is equal to the second global IP address included in the second global address information. If the first global IP address and the second global IP address are not equal, a P2P connection request is transmitted with the address information corresponding to the global IP address as the destination, and a response is returned from the communication device of the communication partner If the first global IP address and the second global IP address are equal to each other when it is determined that the P2P communication is started using the address information used as the destination, the second WAN side address information and the second local IP address A P2P connection request is sent to any one of the address information as a destination. And Shin, when the communication device of the communication partner response returns, using the address information used as the destination, may determine to start P2P communication.

  As a result, the communication device determines whether the communication with the communication partner is communication via the Internet or communication within the home network, and then attempts P2P communication using appropriate address information. It will be. Therefore, useless processing is omitted.

  Preferably, the used address information judging means judges whether or not the first and second global address information and the first and second WAN side address information belong to a predetermined type. Depending on the type to which the first and second global address information and the first and second WAN address information belong, the address information used as the destination is changed to the second global address information and the second WAN address information. , And the second local address information in advance, and using the address information according to the type to which the first and second global address information and the first and second WAN address information belong, P2P It may be determined that communication is started.

  The appropriate address information to be used is determined by the network configuration. Therefore, in this way, it is determined what type the first and second global address information and the first and second WAN address information belong to, and the address information to be used is defined in advance according to the type. Also, P2P communication is possible. As a result, the communication apparatus can reduce the number of P2P connection request attempts. Therefore, the time for establishing the P2P communication path is shortened.

  Preferably, the predetermined type indicates a first type indicating that the communication apparatus is connected to the communication partner communication apparatus via the Internet, and indicates that the communication partner communication apparatus is not connected via the Internet. A second type, a third type indicating that the router immediately above the communication device of the communication partner is set to static NAT, and a router that exists immediately above the communication device of the communication partner is set to static NAT Between the communication type communication device of the communication partner and the Internet, the fifth type indicating that there is only one router between the communication device of the communication partner and the Internet, and between the communication device of the communication partner and the Internet. A sixth type indicating that there are at least two routers, a first WAN side IP address and a second WAN side included in the first WAN side address information A seventh type indicating that the second WAN side IP address included in the address information matches; a first WAN side IP address and a second WAN side address information included in the first WAN side address information; An eighth type indicating that the second WAN-side IP address included in the IP address does not match, a ninth type indicating that a router existing immediately above the own device is set to static NAT, and the own device A tenth type indicating that a static NAT is not set for a router immediately above, an eleventh type indicating that only one router exists between the own device and the Internet, and A twelfth type indicating that there are at least two routers to the Internet, and the used address information determining means includes the first and second global address information. In addition, depending on the type to which the first and second WAN address information belongs, the second WAN address information, the second local address information, or the source address information in the communication path connection request from the communication terminal of the communication partner It is preferable to determine whether to start P2P communication using any one of the address information, or to switch the P2P communication method to start P2P communication.

  Thereby, when the number of routers existing between the Internet and the user terminal is two or less, it can be expected that P2P communication is almost certainly realized.

  Preferably, the P2P communication processing unit determines to start the P2P communication using the P2P communication method or the STUN communication method via the server when the communication path for the P2P communication with the communication partner communication device is not established. Good.

  Thereby, even when there are three or more routers between the Internet and the user terminal, it can be expected that P2P communication is almost certainly realized.

  Preferably, the used address information judging means selects one address based on the first and second global address information, the first and second WAN side address information, and the first and second local address information. The information is used to determine whether or not P2P communication with the communication apparatus of the communication partner is possible, and the P2P communication processing means cannot perform P2P communication with the communication apparatus of the communication partner by the use address information determination means. If it is determined, P2P communication may be determined to be started using the P2P communication method or STUN communication method via the server.

  As a result, it is determined whether or not P2P communication is possible using the exchanged address information. If it is not possible, the P2P communication method is switched. Therefore, useless trials and processes are omitted, and P2P communication can be realized more quickly.

  Preferably, NAT setting change requesting means for deleting an unnecessary address translation rule set in the router may be further provided.

  Thereby, useless address translation rule settings are deleted, and the processing load on the router can be reduced.

  Preferably, after the start of P2P communication, it is preferable to further include a NAT setting change request means for changing the address conversion rule set in the router to a partner limited type that limits the communication partner.

  Thereby, security can be improved.

  The present invention is also a method for P2P communication between a communication device connectable to a network including the Internet and another communication device, which communicates with a server on the network and is assigned to the own device. Obtaining information on the Internet address as the first global address information, and information on the WAN address assigned to the router immediately above the own device as the first WAN address information A step of acquiring, a step of acquiring information relating to an address on the local network assigned to the own device as the first local address information, and a step on the other communication device via a server on the network. 1 global address information, first WAN side address information, and first A step of notifying the local address information, and second global address information that is information related to an address on the Internet assigned to another communication device via a server on the network, which exists immediately above the other communication device. Second WAN address information that is information about addresses on the WAN side assigned to the router, and second local address information that is information about addresses on the local network assigned to other communication devices. Obtaining, and determining a method capable of P2P communication based on the first and second global address information, WAN address information, and local address information.

  The present invention also provides a program for operating a computer device so that a computer device connectable to a network including the Internet performs P2P communication with another computer device. Communicating to obtain information about the address on the Internet assigned to the own device as first global address information, and about the address on the WAN side assigned to the router immediately above the own device Obtaining information as first WAN address information, obtaining information regarding an address on the local network assigned to the own device as first local address information, and for other computer devices , Server on the network Via the step of notifying the first global address information, the first WAN side address information, and the first local address information through the server on the network Second global address information, which is information related to addresses in the network, second WAN side address information, which is information related to addresses on the WAN side assigned to routers immediately above other computer devices, and other computers Obtaining second local address information, which is information relating to an address on the local network assigned to the device, based on the first and second global address information, WAN side address information, and local address information , P2P communication possible It determines to execute the steps.

  The present invention is a system formed on a network including the Internet, and includes a first communication device and a second communication device that can be connected to the network, and the first and second communication devices include: Global address information acquisition means that communicates with a server on the network and acquires information on the Internet address assigned to the own device as first global address information, and is assigned to a router directly above the own device. WAN-side address information acquisition means for acquiring information on the address on the WAN side as the first WAN-side address information, and information on the address on the local network assigned to the own device as the first local address Local address information acquisition means to acquire information and P2P communication Address information notifying means for notifying the communication device of the communicating party of the first global address information, the first WAN side address information, and the first local address information via a server on the network, and a network The second global address information, which is information related to the address on the Internet assigned to the communication device of the communication partner via the above server, the WAN side assigned to the router immediately above the communication device of the communication partner Address information acquisition means for acquiring second WAN address information that is information relating to the address of the second address, and second local address information that is information relating to the address on the local network assigned to the communication device of the communication partner. Comprising first and second global address information, WAN Address information, and on the basis of the local address information, determines a P2P communication that is available method.

  Further, the present invention is an integrated circuit built in a communication device connectable to a network including the Internet, and communicates with a server on the network to obtain information on the Internet address assigned to the own device. Global address information acquisition means to acquire as first global address information, and WAN address to acquire information on the address on the WAN side assigned to the router immediately above the own device as first WAN address information Information acquisition means, local address information acquisition means for acquiring information on an address on the local network assigned to the own apparatus as first local address information, and a communication apparatus of a communication partner who desires P2P communication The first group via a server on the network Address information notifying means for notifying global address information, first WAN side address information, and first local address information, and an address on the Internet assigned to a communication device of a communication partner via a server on the network Second global address information that is information, second WAN address information that is information related to a WAN side address assigned to a router immediately above the communication partner communication device, and assignment to the communication partner communication device Address information acquisition means for acquiring second local address information that is information relating to addresses on the local network, and includes first and second global address information, WAN address information, and local address information. P2P communication is possible based on To determine the equation.

  The present invention is also a computer-readable recording medium storing a program for operating a computer device so that the computer device connectable to a network including the Internet performs P2P communication with another computer device. A program communicates with a server on a network to a computer device to obtain information on an address on the Internet assigned to the device as first global address information, and exists immediately above the device. Obtaining information on the address on the WAN side assigned to the router as first WAN side address information, and information on the address on the local network assigned to the own device as first local address information Step to get And notifying the other computer apparatus of the first global address information, the first WAN address information, and the first local address information via the server on the network, and the server on the network The second global address information, which is information relating to addresses on the Internet assigned to other computer devices, and the addresses on the WAN side assigned to routers located immediately above other computer devices. Obtaining second WAN address information that is information, and second local address information that is information relating to an address on a local network assigned to another computer apparatus; and first and second global addresses Address information, WAN side address information, Based on the local address information in beauty, and a step of determining a P2P communication that is available method.

  In addition, the present invention is a communication device connectable to a network, communicates with a server on the network, and transmits information about an address assigned to the own device on a subnetwork to which the server belongs, as a first global address. Global address information acquisition means for acquiring as information, WAN side address information acquisition means for acquiring, as first WAN side address information, information related to the address on the WAN side assigned to the router immediately above the own device, A local address information acquisition means for acquiring information on an address on the local network assigned to the own apparatus as first local address information, and a server on the network for a communication apparatus of a communication partner who desires P2P communication. Via the first global address information, the first The address information notifying means for notifying the WAN side address information and the first local address information, and the second information which is information on the address on the sub-network assigned to the communication device of the communication partner via the server on the network. Global address information, second WAN-side address information that is information related to the address on the WAN side that is assigned to the router immediately above the communication device of the communication partner, and the local that is assigned to the communication device of the communication partner Address information acquisition means for acquiring second local address information that is information relating to addresses on the network, and based on the first and second global address information, WAN side address information, and local address information, P2P Determine a method that allows communication.

  As described above, according to the present invention, it is possible to provide a communication apparatus, method, and program capable of realizing P2P communication even in a communication environment in which a network is configured in a complicated manner. Furthermore, a communication device, method, and program capable of realizing P2P communication even when the network configuration dynamically changes are provided.

  These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, an address refers to an IP address. The address information includes an IP address and a port number. The address information is classified into global address information, WAN side address information, and local address information. The IP address is classified into a global IP address, a WAN side IP address, and a local IP address. Accordingly, the global address information includes a global IP address and a port number. The WAN side address information includes a WAN side IP address and a port number. The local address information includes a local IP address and a port number.

(First embodiment)
FIG. 1A is a diagram illustrating an example of a network configuration in which P2P communication control according to the first embodiment of the present invention is executed. In FIG. 1A, the entire network includes a home network 1, a home network 2, a P2P server 3, and the Internet 4. Note that the number of home networks and the number of P2P servers are not limited to the example shown in FIG. 1A.

  The home network 1 includes a plurality of routers 2A, 2B, 2C and a plurality of user terminals 1a, 1b, 1c, 1d. Note that the number of routers and the number of user terminals in the home network 1 are not limited to the example shown in FIG. 1A. The routers 2A, 2B, and 2C include a NAT function unit 21 that sets an address conversion rule for converting address information of the lower network into address information of the upper network. The routers 2A, 2B, and 2C enable connection between the Internet 4 and a home network (hereinafter referred to as a subnet) or connection between a plurality of home subnets. In the present invention, NAT is a concept including NAT (Network Address Port Translation) that converts an address to 1 to N using a port number in addition to a narrowly defined NAT that converts an address to 1 to 1. .

  The home network 2 includes a router 2D and a user terminal 1e. The router 2D includes a NAT function unit 21. The router 2D enables connection between the user terminal 1e and the Internet 4. Note that the number of routers and the number of user terminals in the home network 2 are not limited to the example shown in FIG. 1A.

  The P2P server 3 has a communication path between the user terminals 1a to 1e. The P2P server 3 manages the identification information of the user terminals 1a to 1e and relays communication between the user terminals, and a global assigned to each user terminal by the router 2C when performing communication via the Internet. A server having a function of notifying each user terminal of address information. The P2P server only needs to have the above function. Therefore, any server having the above functions can be a change of a P2P server. Here, the P2P server 3 is connected to the Internet. However, the P2P server may exist in the home network as long as the above functions can be realized. When the P2P server exists in the home network, the function of the P2P server may be incorporated in the router.

  The Internet 4 performs communication using global address information.

  FIG. 2 is a block diagram illustrating a hardware configuration of the user terminals 1a to 1e which are communication apparatuses. Since the user terminals 1a to 1e have the same hardware configuration, the hardware configuration of the user terminal 1a will be described below as a representative.

  In FIG. 2, the user terminal 1 a includes a central processing unit 10, a main storage device 11, an auxiliary storage device 12, a communication device 13, and an input / output device 14. The central processing unit 10 causes the main storage device 11 to read a program stored in the auxiliary storage device 12 or the main storage device 11, executes the program, and controls the overall operation of the user terminal 1a. The main storage device 11 stores information necessary for the operation of the central processing unit 10. The auxiliary storage device 12 stores information necessary for the operation of the central processing unit 10 and stores a program to be executed by the central processing unit 10 in advance. Here, it is assumed that a program for realizing P2P communication (hereinafter referred to as a P2P communication program) is stored in the auxiliary storage device 12. The communication device 13 is a device for realizing communication with an external device. The input / output device 14 is a device for receiving input from a user and a device for outputting a processing result by the central processing unit 10. The user terminal 1a implements P2P communication with other user terminals by executing the P2P communication program.

  FIG. 3A is a diagram illustrating an example of IP addresses assigned to the user terminals 1 a to 1 e and the P2P server 3. As shown in FIG. 3A, the user terminals 1a and 1b under the router 2A have IP addresses of “192.168.0.0.X”, “192.168.0.100” and “192”, respectively. .168.0.101 "is assigned. The user terminal 1c under the router 2C is assigned “192.168.10.2”, which is an IP address of the “192.168.10.X” system. The user terminal 1d under the router 2B is assigned “192.168.1.10”, which is an IP address of the “192.168.1.X” system. The user terminal 1e under the router 2D is assigned “192.168.0.30” which is an IP address of the “192.168.0.X” system. “132.186.9.10” is assigned to the P2P server 3. Since the P2P server 3 is directly connected to the Internet, the IP address assigned to the P2P server 3 is a global IP address.

  FIG. 3B is a diagram illustrating an example of a WAN-side IP address and a LAN-side IP address assigned to a router. As shown in FIG. 3B, “192.168.10.5” is assigned as the WAN-side IP address and “192.168.0.1” is assigned as the LAN-side IP address to the router 2A. Since the IP address under the router 2A is “192.168.0.X” system, the LAN side IP address of the router 2A is “192.168.0.1”. The router 2B is assigned “192.168.10.4” as the WAN side IP address and “192.168.1.255” as the LAN side IP address. Since the IP address under the control of the router 2B is “192.168.1.X”, the LAN side IP address of the router 2B is “192.168.1.255”. The router 2C is assigned “133.152.6.50” as the WAN side IP address and “192.168.10.1” as the LAN side IP address. Since the IP address under the control of the router 2C is “192.168.10.X”, the LAN side IP address of the router 2C is “192.168.10.1”. Further, since the router 2A is under the control of the router 2C, the WAN-side IP address of the router 2A is “192.168.10.5” which is the “192.168.10.X” system. Similarly, since the router 2B is under the control of the router 2C, the WAN side IP address of the router 2B is “192.168.10.4” which is the “192.168.10.X” system. Since the router 2C is directly connected to the Internet 4, the WAN side IP address of the router 2C is a global IP address. The router 2D is assigned “133.121.2.15” as the WAN-side IP address and “192.168.0.1” as the LAN-side IP address. Since the router 2D is directly connected to the Internet 4, the WAN side IP address of the router 2D is a global IP address. Since the router 2A and the router 2D exist in different home networks, the LAN side IP addresses assigned to the routers 2A and 2D overlap, but there is no problem.

  FIG. 4 is a block diagram showing a functional configuration of a user terminal which is a communication device when a P2P communication program is executed. 4, the user terminal includes a global address information acquisition unit 101, a NAT setting request unit 102, a WAN side address information acquisition unit 103, a local address information acquisition unit 104, an address information notification unit 105, and an address information acquisition. Unit 106, used address information determination unit 107, and P2P communication processing unit 108.

  The global address information acquisition unit 101 communicates with the P2P server 3 and acquires global address information assigned to the own device. The global address information acquisition unit 101 stores the acquired global address information in a storage device (not shown).

  The NAT setting request unit 102 requests a router immediately above the own device (directly connected to the own device) to set an address translation rule, and sets the address translation rule.

  The WAN-side address information acquisition unit 103 communicates with the router and acquires WAN-side address information assigned to the own device based on the set address conversion rule. The WAN address information acquisition unit 103 stores the acquired WAN address information in a storage device (not shown).

  The local address information acquisition unit 104 acquires local address information assigned to the own device. For example, the local address information acquisition unit 104 acquires local address information assigned to the own device stored in a storage device (not shown). Hereinafter, the global address information, WAN side address information, and local address information assigned to the own device are referred to as first global address information, first WAN side address information, and first local address information.

  The address information notification unit 105 is acquired by the first global address information acquired by the global address information acquisition unit 101, the first WAN address information acquired by the WAN side address information acquisition unit 103, and the local address information acquisition unit 104. The first local address information is notified via the P2P server 3 to the communication device of the communication partner who desires P2P communication. In addition, when notifying address information, the server through which a user terminal passes may be other than the P2P server 3.

  The address information acquisition unit 106 acquires, via the P2P server 3, global address information, WAN address information, and local address information assigned to the communication apparatus of the communication partner. Hereinafter, the global address information, WAN address information, and local address information assigned to the communication device of the communication partner are referred to as second global address information, second WAN address information, and second local address information. . The address information acquisition unit 106 may acquire the address information assigned to the communication device of the communication partner via a server other than the P2P server 3.

  The used address information determining unit 107 uses any one of the second global address information, the second WAN side address information, and the second local address information acquired by the address information acquiring unit 106. Thus, it is determined whether or not to start P2P communication with the communication apparatus of the communication partner. When it is determined that the P2P communication with the communication apparatus of the communication partner is started using any one of the address information, the use address information determination unit 107 sends the address information to be used to the P2P communication processing unit 108. On the other hand, if it is determined that the P2P communication with the communication partner communication device is started without using any address information, the use address information determination unit 107 sends the P2P communication processing unit 108 to the communication partner communication device. Is instructed to wait for a P2P communication request or to switch the P2P communication method.

  When the P2P communication processing unit 108 is instructed by the use address information determination unit 107 to start P2P communication using any one of the address information, the P2P communication processing unit 108 uses the address information to communicate with the communication partner. Start P2P communication with the device. When the use address information determination unit 107 instructs the P2P communication processing unit 108 to wait for a P2P communication request from the communication partner communication device, the P2P communication request is sent from the communication partner communication device. For example, the source address information of the request is used to respond to the communication device of the communication partner, and P2P communication is started. When the P2P communication processing unit 108 is instructed by the use address information determining unit 107 to start the P2P communication by switching the P2P communication method, the P2P communication method is changed to the P2P communication method via the P2P server 3 or STUN. P2P communication is started using the communication method. Here, the STUN communication method is a communication method disclosed in RFC 3489-STUN-Simple Traversal Of User Data Protocol (UDP) Through Network Address Translators (NATS).

  Hereinafter, operations of the user terminal and the P2P server 3 when performing P2P communication will be described. In the following, the operation will be described with reference to the user terminal on the network shown in FIG. 1A as needed. However, the P2P communication method of the present invention is not applied only to the network shown in FIG. 1A. Further, the operation will be described while illustrating the IP address so that the operation is easy to understand, but the P2P communication method of the present invention is not applied only to the illustrated IP address. The operation of the user terminal is realized by executing a P2P communication program.

  First, each user terminal executes a process of registering identification information (identification information registration process) with respect to the P2P server 3 before starting P2P communication. In the following description, it is assumed that the user terminal 1a executes the identification information registration process, but other user terminals operate in the same manner.

  FIG. 5 is a flowchart showing the operation of the user terminal 1a and the P2P server 3 when executing the identification information registration process. Hereinafter, the operations of the user terminal 1a and the P2P server 3 when executing the identification information registration process will be described with reference to FIG. In FIG. 5, the operation of the user terminal 1a is indicated by a single line frame. The operation of the P2P server 3 is indicated by a double line frame.

  First, the user terminal 1a establishes a communication path with the P2P server 3 (step S301). The establishment of the communication path can be realized by a known method. Communication from the user terminal 1a to the P2P server 3 is communication from the LAN side of the router to the WAN side, as in normal Web access. Therefore, a communication path is automatically secured by a known dynamic NAT. The dynamic NAT automatically secures a return communication path from the P2P server 3 to the user terminal 1a, including an intermediate path, corresponding to the forward path from the user terminal 1a to the P2P server 3. That is, in the router on the communication path, a NAT conversion table according to the dynamic NAT address conversion rule is created by dynamic NAT setting. Here, NAT in which the address translation rule changes for each NAT setting is referred to as dynamic NAT.

  Next, the user terminal 1a transmits its own identification information to the P2P server 3 (step S302). For example, the identification information is information for identifying the user terminal such as a mail address of the user terminal 1a.

  Next, the P2P server 3 associates information related to a communication path with the user terminal 1a (hereinafter referred to as communication path information) and identification information of the user terminal 1a and manages them as an identification information management table (step). S303). Here, the communication path information is a concept including information on a destination address and a port number for transmitting a message to the user terminal 1a.

  FIG. 6 is a diagram illustrating an example of the identification information management table. As shown in FIG. 6, for example, the identification information management table includes communication path information and additional information in association with the identification information.

  As described above, the identification information registration process is executed, whereby the identification information of each user terminal is registered in the P2P server 3 together with the communication path information.

  When starting P2P communication between the first user terminal and the second user terminal, the first and second user terminals execute processing for exchanging necessary information. A process executed by a user terminal on the transmission side (for example, the first user terminal) to exchange necessary information is referred to as a transmission side information exchange process. The process executed by the user terminal (for example, the second user terminal) on the receiving side in order to exchange necessary information is referred to as a receiving side information exchange process.

  FIG. 7 is a flowchart showing the operation of the user terminal on the transmission side and the operation of the P2P server 3 for executing the transmission side information exchange process. Hereinafter, the operation of the user terminal on the transmission side that executes the information exchange process on the transmission side and the operation of the P2P server will be described with reference to FIG. In FIG. 7, the operation of the calling user terminal is indicated by a single-line frame. The operation of the P2P server is indicated by a double line frame.

  First, the originating user terminal that desires to start communication transmits an address information notification request message to the P2P server 3, receives an address information notification response message from the P2P server 3, and starts from the address information notification response message. Global address information is acquired (step S501). The operation in step S501 is realized by the global address information acquisition unit 101. In step S501, the calling user terminal may acquire only the global IP address as the global address information.

  FIG. 8A is a diagram illustrating an example of a format of an address information notification request message. FIG. 8B is a diagram illustrating an example of a format of an address information notification response message.

  As shown in FIG. 8A, the address information notification request message includes a communication header, message identification information, and additional information. The originating user terminal describes the address information of the originating user terminal itself as source address information and the global address information of the P2P server 3 as destination address information in the communication header. Each time this address information notification request message is routed through the router, the source address information in the communication header is replaced with the WAN side address information of the routed router, that is, the set of the WAN side IP address and the port number. Therefore, when the address information notification request message reaches the P2P server 3, the source address information in the communication header is a pair of the WAN side IP address and the port number of the router that has passed last (global IP address and port). It is replaced with a pair with a number). In the message identification information, information indicating a message requesting notification of address information is described. The additional information includes authentication information and the like.

  In the above-described example, the case where the P2P server is connected to the Internet has been described. However, when the user terminal that performs communication is connected to the same private network, the P2P server is not on the Internet but the private network. It may exist in the inside. At this time, the P2P server must be connected to the same router (with NAT function) for both user terminals performing P2P communication, or connected to a higher-level (WAN side) router (with NAT function). (See FIG. 1B).

  In this case, the global address information is information on the address space of the LAN side segment of the router to which the P2P server is connected. That is, the global address information is information relating to an address assigned to the user terminal on the subnetwork to which the P2P server belongs. Therefore, the global address information is actually address information in the private address space. However, the procedure used for connection is the same as when the P2P server is connected to the Internet.

  In other words, the user terminal communicates with the P2P server 3 on the network to obtain information on the address assigned to the own device on the subnetwork (for example, 192.168.10.X series) to which the P2P server 3 belongs. Obtained as first global address information. In addition, the user terminal acquires information on the address on the WAN side assigned to the router immediately above the own device as first WAN side address information. Further, the user terminal acquires information regarding an address on the local network assigned to the user terminal as first local address information. Then, the user terminal sends the first global address information, the first WAN side address information, and the first local address information to the communication device of the communication partner who desires the P2P communication via the P2P server 3. Notice. Thereafter, the user terminal, via the P2P server 3, on the subnetwork to which the P2P server 3 belongs, the second global address information that is information related to the address assigned to the communication device of the communication partner and the communication of the communication partner. The second WAN side address information, which is information related to the WAN address assigned to the router immediately above the device, and the information related to the address on the local network assigned to the communication device of the communication partner Second local address information is acquired. The user terminal determines a method capable of P2P communication based on the acquired first and second global address information, WAN side address information, and local address information.

  As shown in FIG. 8B, the address information notification response message includes a communication header, message identification information, address information, and additional information. The P2P server 3 describes the source address information and the destination address information in the communication header. In the message identification information, information indicating that the message is a response to the address information notification request is described. The additional information includes authentication information and the like. When receiving the address information notification request message, the P2P server 3 extracts the source address information described in the communication header of the address information notification request message. As described above, the source address information is a set of the WAN side IP address (global IP address) and the port number of the router that has passed through last. The P2P server 3 writes the extracted source address information (global IP address and port number) in the address information column. The P2P server 3 transmits the created address information notification response message according to the communication path information (see FIG. 6). The address information notification response message transmitted from the P2P server 3 traces the router in the reverse direction and reaches the originating user terminal. At this time, a NAT conversion table according to an address conversion rule by dynamic NAT setting is used.

  As described above, the source address information in the communication header of the address information notification request message taken out by the P2P server 3 is the address information converted by using the dynamic NAT by the last passed router, that is, dedicated to the user terminal. Address information to which the port number is assigned and global address information assigned to the user terminal. For example, when the user terminal 1a transmits an address information notification request message, the source address information is composed of the global IP address of the router 2C and the port number set by the router 2C toward the user terminal 1a. However, since dynamic NAT setting is used, this global address information generally accepts only communication from the P2P server 3.

  Next, the originating user terminal compares the IP address assigned to it with the global IP address included in the address information notification response message. If the IP addresses are different, the originating user terminal uses the UPnP / IGD protocol or the like. The WAN side IP address of the router is acquired (step S502). In this specification, the upper router (Upstream Router) refers to a router that exists on the Internet side when viewed from the user terminal. When the IP address assigned to itself is different from the global IP address included in the address information notification response message, it means that the originating user terminal is connected to the Internet 4 via the router. Therefore, the IP address assigned to itself is a local IP address. For example, when the UPnP / IGD protocol is used, the calling user terminal can acquire the WAN-side IP address of the upper router by transmitting a GetExternalIPAddress action message to the upper router. Here, the IP address is obtained, but the port number is not obtained.

  When the IP address assigned to itself is different from the global IP address, the calling user terminal performs NAT setting on the upper router using UPnP / IGD protocol or the like, and WAN side address information set in the upper router Is stored (step S503). The operation in step S503 is realized by the NAT setting request unit 102 and the WAN address information acquisition unit 103.

  For example, when the UPnP / IGD protocol is used, the calling-side user terminal can perform NAT setting to the upper router by transmitting an AddPortMapping action message to the upper router. The transmission-side user terminal informs the upper router of the port number to be set by sending an AddPortMapping action message, and requests NAT setting with the port number. The NAT setting in step S503 must be maintained regardless of the start and end of communication. In this way, the NAT setting in which the setting is maintained regardless of the start and end of communication is referred to as a static NAT setting. The dynamic NAT setting is automatically set with the start of communication and is canceled with the end of communication. On the other hand, the static NAT setting can be set regardless of the start and end of communication. The static NAT setting can be set even before communication is started. The static NAT setting is maintained until it is released.

  When storing the WAN address information, since the originating user terminal has already acquired the WAN address information in step S502, the WAN address information need not be acquired in step S503. In response to the operation in step S503 in the originating user terminal, the upper router performs static NAT setting and creates a NAT translation table according to the static NAT address translation rule.

  As a matter of course, the calling user terminal knows or is given in advance the identification information of the other party who wishes to communicate. The calling user terminal specifies identification information of the communication partner and transmits a communication start request message to the P2P server 3. At this time, the calling-side user terminal has its own identification information, its own global address information (first global address information), its own local address information (first local address information), and the WAN address of the upper router. Information (first WAN address information) is transmitted (step S504). The operation in step S504 is realized by the address information notification unit 105.

  FIG. 9A is a diagram illustrating an example of a format of a communication start request message. As shown in FIG. 9A, the communication start request message includes a communication header, message identification information, transmission source user terminal identification information, transmission destination user terminal identification information, global address information (first global address information), and WAN address information (first WAN address information) of the upper router, own local address information (first local address information), and additional information are included.

  The message identification information is information indicating a communication start request. The transmission source user terminal identification information is identification information of the calling user terminal. The transmission destination user terminal identification information is identification information of a communication partner user terminal. The global address information is the global address information (global IP address and port number) acquired in step S501. The WAN side address information of the upper router is the WAN side address information (WAN side IP address and port number) stored in step S503. The own local address information is a local IP address set in advance and a port number used by itself. Note that the local address information includes a netmask. If the variable part of the IP address is recognized without a net mask, the net mask may not be included. The additional information is authentication information or the like.

  In step S502, if the IP address assigned to itself matches the global IP address included in the address information notification response message, the calling user terminal connects directly to the Internet 4 without going through the router. Means that That is, its own local IP address is a global IP address. In such a case, the originating user terminal uses the global address information as the IP address and port number assigned to itself, the WAN address information as the IP address and port number assigned to itself, and the local address information as A communication start request message is transmitted to the P2P server 3 as the IP address and port number assigned to itself.

  The P2P server 3 receives the message from the user terminal, refers to the message identification information, and recognizes that the received message is a communication start request. The P2P server 3 that has recognized that it is a communication start request refers to the transmission destination user terminal identification information and recognizes the identification information of the transmission destination user terminal. Then, the P2P server 3 refers to the identification information management table and determines a communication path to the transmission destination user terminal based on the communication path information corresponding to the recognized identification information. The P2P server 3 transmits the communication start request message received from the originating user terminal to the destination user terminal so as to pass through the determined communication path to the destination user terminal (step S505). Thus, the communication start request message from the calling user terminal is transferred to the destination user terminal that is the communication partner.

  It should be noted that authentication information is preferably added to the address information notification request message and the communication start request message. It is preferable that the P2P server 3 uses the authentication information for each user terminal managed by the identification information management table to check whether the communication is from a legitimate user terminal and to increase security. Further, when transferring the address information notification response message or the communication start request message, the P2P server 3 may increase security by attaching authentication information indicating the validity of the P2P server 3 to the message.

  FIG. 10 is a flowchart showing the operation of the called user terminal and the operation of the P2P server 3 for executing the called party information exchange process. Hereinafter, with reference to FIG. 10, the operation of the user terminal on the incoming side that executes the information exchange process on the incoming side and the operation of the P2P server 3 will be described. In FIG. 10, the operation of the receiving user terminal is indicated by a single-line frame. The operation of the P2P server is indicated by a double line frame.

  First, the receiving-side user terminal receives the communication start request message transferred from the P2P server 3 and extracts the identification information of the transmission source (calling-side user terminal), and the global address information ( First global address information), WAN side address information (first WAN side address information), and local address information (first local address information) are extracted as source address information. The called user terminal stores the extracted identification information of the transmission source and the address information in association with each other (step S601). The operation in step S601 is realized by the address information acquisition unit 106.

  Next, the called user terminal transmits an address information notification request message to the P2P server 3 and receives its own global address information (second global address information) from the address information notification response message returned from the P2P server 3. ) Is acquired (step S602). The process in step S602 is basically the same as the process (step S501) in which the calling user terminal acquires global address information. The operation in step S602 is realized by the global address information acquisition unit 101. In step S602, the receiving user terminal may acquire only the global IP address as the global address information.

  Next, the called user terminal compares the IP address assigned to itself with the global IP address included in the address information notification response message, and if the IP address is different, uses the UPnP / IGD protocol or the like. The WAN side address information of the router is acquired (step S603). When the IP address assigned to itself is different from the global IP address included in the address information notification response message, it means that the originating user terminal is connected to the Internet 4 via the router. Therefore, the IP address assigned to itself is a local IP address. For example, when the UPnP / IGD protocol is used, the receiving-side user terminal can acquire the WAN-side IP address information of the upper router by transmitting a GetExternalIPAddress action message to the upper router. Here, the IP address is obtained, but the port number is not obtained.

  When the IP address assigned to itself is different from the global IP address, the called-side user terminal uses the UPnP / IGD protocol or the like to perform static NAT setting in the upper router, and the WAN side set in the upper router Address information is stored (step S604). For example, when the UPnP / IGD protocol is used, the called-side user terminal can perform NAT setting for the upper router by transmitting an AddPortMapping action message to the upper router. The operations in steps S603 and S604 are realized by the NAT setting request unit 102 and the WAN address information acquisition unit 103.

  Next, the receiving user terminal specifies identification information of the calling user terminal and transmits a communication start response message to the P2P server 3. At this time, the called user terminal has its own identification information, its own global address information (second global address information), the WAN side address information of the upper router (second WAN side address information), and its own local address. Information (second local address information) is transmitted (step S605). The operation in step S605 is realized by the address information notification unit 105.

  FIG. 9B is a diagram illustrating an exemplary format of a communication start response message. As shown in FIG. 9B, the communication start request message includes a communication header, message identification information, transmission source user terminal identification information, transmission destination user terminal identification information, global address information (second global address information), and WAN address information (second WAN address information) of the upper router, own local address information (second local address information), and additional information are included.

  The message identification information is information indicating that the message is a response to the communication start request. The transmission source user terminal identification information is identification information of the receiving user terminal. The transmission destination user terminal identification information is identification information of the transmission-side user terminal of the communication partner. The global address information is the global address information (global IP address and port number) acquired in step S602. The WAN side address information of the upper router is the WAN side address information (WAN side IP address and port number) stored in step S604. The own local address information is a local IP address set in advance and a port number used by itself. Note that the local address information includes a netmask. If the variable part of the IP address is recognized without a net mask, the net mask may not be included. The additional information is authentication information or the like.

  In step S603, if the IP address assigned to itself matches the global IP address included in the address information notification response message, the receiving user terminal directly connects to the Internet 4 without going through the router. Means that That is, its own local IP address is a global IP address. In such a case, the called user terminal uses the global address information as the IP address and port number assigned to itself, the WAN address information as the IP address and port number assigned to itself, and the local address information as A communication start response message is transmitted to the P2P server 3 as the IP address and port number assigned to itself.

  The P2P server 3 receives the message from the user terminal, checks the message identification information, and recognizes that it is a communication start response message. The P2P server 3 that has recognized that it is a communication start response message refers to the transmission destination user terminal identification information and recognizes the identification information of the transmission destination user terminal. Then, the P2P server 3 refers to the identification information management table and determines a communication path to the transmission destination user terminal based on the communication path corresponding to the transmission destination user terminal identification information. The P2P server 3 transmits the communication start response message received from the receiving user terminal so as to pass through the communication path to the transmission destination user terminal (step S606). As a result, the communication start response message from the receiving user terminal is transferred to the calling user terminal as the communication partner.

  Upon receiving the communication start response message of the called user terminal, the calling user terminal sends the global address information (second global address information) and WAN address assigned to the called user terminal from the communication start response message. Information (second WAN side address information) and local address information (second local address information) are acquired. This operation is realized by the address information acquisition unit 106.

  The transmission / reception of the communication start request message and the communication start response message may be performed via a server other than the P2P server 3.

  Through the above-described calling-side information exchange processing and receiving-side information exchange processing, an event to perform P2P communication between user terminals is notified via the P2P server 3, and global address information, WAN side address information and local address information are exchanged. The user terminal starts P2P communication based on the acquired global address information, WAN side address information, and local address information.

  Next, a procedure for actually starting P2P communication between user terminals having exchanged address information will be described.

  FIG. 11A and FIG. 11B are flowcharts showing operations when user terminals having exchanged address information actually perform P2P communication. The operations shown in FIG. 11A and FIG. 11B may be performed by a user terminal on the transmission side, a user terminal on the reception side, or a user terminal on the transmission side and the reception side. Which user terminal performs the operations shown in FIGS. 11A and 11B may be determined in advance, or may be determined by a communication start request message or a communication start response message. The operations shown in FIGS. 11A and 11B are realized by the used address information determination unit 107 and the P2P communication processing unit 108.

  First, the user terminal that has acquired the address information of the user terminal that is the communication partner by the caller information exchange process and the callee information exchange process is based on the address information of the communication partner and its own address information. And whether or not P2P communication is possible, that is, whether or not a communication path for P2P communication can be secured (step S900). If it is determined that a communication path for P2P communication can be secured, the user terminal proceeds to the operation of step S901. On the other hand, when it is determined that a communication path for P2P communication cannot be secured, the user terminal exchanges user data via the P2P server in the same manner as the transmission / reception of the communication start request message and the transmission / reception of the communication start response message. The connection method is switched, such as switching to communication. Note that the user terminal performs the determination in step S900 only when the global IP address is different.

  12A and 12B are diagrams illustrating an example of address information when a communication path for P2P communication cannot be secured. FIG. 12A shows an example of a communication start request message from the user terminal 1a. FIG. 12B shows an example of a communication start response message from the user terminal 1d. Here, for the user terminals 1a and 1b, the WAN-side address information is “WAN_IP :−( cannot be acquired)”. That is, neither of the user terminals 1a and 1b can acquire the address information of the upper router. This is generally because the upper router does not support the UPnP / IGD protocol. Further, both the user terminals 1a and 1d have different global IP addresses and local IP addresses. Therefore, it can be said that both the user terminals 1a and 1d exist under the upper router. Furthermore, the global IP address of the user terminal 1a matches the global IP address of the user terminal 1b, and the port numbers are different. Therefore, it can be seen that the user terminals 1a and 1d are both under the common router. Therefore, it can be seen that the user terminals 1a and 1d do not need to communicate via a route via the Internet. When there is a router in the communication path, communication from the WAN side of the router to the LAN side cannot be realized unless NAT setting is performed. In the example shown in FIGS. 12A and 12B, NAT setting is not performed for the routers 2A and 2B immediately above the user terminals 1a and 1d. In addition, the router cannot newly set a NAT. Therefore, as a result, in the example illustrated in FIGS. 12A and 12B, the user terminals 1a and 1d are determined to be incapable of P2P communication based on the determination in step S908. In other words, as in this example, when the global IP addresses are the same, P2P communication is impossible using only the information obtained as a result of the originating side information exchange process and the terminating side information exchange process. It cannot be determined whether or not. Therefore, the user terminal tries P2P communication using the local address information and the WAN address information, confirms that the P2P connection cannot be performed, and determines that the P2P communication is impossible. Therefore, when the address information shown in FIGS. 12A and 12B is address information between the user terminal 1a and the user terminal 1d, it is determined that P2P communication is impossible. This is because there is a router that is not set to NAT in the higher-level router on the other side, so the message transmitted from the user terminals 1a and 1d cannot be forwarded to the correct other party and is not received by the other side. It is. Note that, for example, a message is an entire control packet for connection of a P2P communication path such as a request message or a response message. When the address information shown in FIGS. 12A and 12B is address information between the user terminal 1a and the user terminal 1c, the router 2A and the router 2C do not support UPnP. It can be said that it can no longer be acquired. However, in this case, when a communication request is started from the user terminal 1a, P2P communication can be performed by dynamic NAT.

  13A and 13B are diagrams illustrating other examples of address information when a communication path for P2P communication cannot be secured. FIG. 13A is an example of a communication start request message from the user terminal 1a. FIG. 13B is an example of a communication start request message from the user terminal e. In the example of FIG. 13B, it is shown that the user terminal 1e has a router at the upper level, but the router 2D directly above is not set to NAT. On the other hand, in the example of FIG. 13A, the NAT of the upper router is set in the user terminal 1a. However, in the example of FIG. 13A, the global IP address and the WAN side IP address are different. Therefore, it can be seen that there is a router above the router directly above. In the highest router, NAT setting that can handle communication between the user terminal 1a and the user terminal 1e is not performed. This is because the user terminal usually cannot perform static NAT setting to a router positioned higher than a certain router. Further, since the global IP address of the user terminal 1a and the global IP address of the user terminal 1e are different, the user terminal 1a and the user terminal 1e need to communicate with each other via a route via the Internet where a router exists in the communication path. . However, since static NAT setting is not performed in the router immediately above the user terminal 1e, it is determined that P2P communication is impossible. This determination can be made only with the information obtained as a result of performing the transmission side information exchange processing and the reception side information exchange processing. Therefore, the user terminal can determine that P2P communication is not possible in step S900.

  As described above, when there is a router for which static NAT setting is not performed, the user terminal determines that P2P communication is not possible.

  In step S900, when it is determined that a communication path for P2P communication cannot be secured, the user terminal switches to communication for exchanging user data via the P2P server 3. However, if it is determined that a communication path for P2P communication cannot be secured, the user terminal uses the global address information and transmits a UDP packet to the global address information of the communication partner using the STUN communication method. Communication may be attempted. That is, when it is determined that a communication path for P2P communication cannot be secured, the user terminal may try P2P communication by the STUN method. Switching of communication methods is realized by the P2P communication processing unit 108.

  In step S901, the user terminal refers to the global address information of the communication partner and determines whether the global IP address of the communication partner matches its own global IP address.

  If the global IP addresses match, the two user terminals attempting P2P communication are user terminals located under the same router. Therefore, the two user terminals can communicate without going through the Internet. If the global IP addresses match, the user terminal proceeds to the operation of step S902.

  On the other hand, if the global IP addresses do not match, the two user terminals attempting P2P communication are user terminals that are not located under the same router. Therefore, the two user terminals communicate via the Internet. If the global IP addresses do not match, the user terminal proceeds to the operation of step S910.

  In step S902, the user terminal transmits a P2P connection request to the local address information of the communication partner.

  After step S902, the user terminal determines whether or not to receive a response from the communication partner that is the transmission destination of the P2P connection request (step S903). When a response from the communication partner is received, a mutual communication path is established. Therefore, after that, the user terminal transmits data for P2P communication to the local address information of the communication partner (step S915).

  On the other hand, when the response from the communication partner cannot be received, the user terminal determines whether or not to receive a request from the communication partner (step S904). When the request from the communication partner is received, the user terminal transmits a response indicating that the P2P connection has been established to the transmission source information described in the header included in the request message (step S905). Thereby, a mutual communication path is established. Therefore, after that, the user terminal transmits data for P2P communication to the transmission source information described in the header (step S916).

  If the request from the communication partner cannot be received in step S904, the user terminal transmits a P2P connection request to the address information on the WAN side of the communication partner (that is, to the router immediately above the communication partner) (step S906). ). Next, the user terminal determines whether or not to receive a response from the communication partner (step S907). When a response from the communication partner is received, a mutual communication path is established. Therefore, after that, the user terminal transmits data for P2P communication to the WAN address information of the communication partner (step S917).

  On the other hand, if the response from the communication partner cannot be received, the user terminal determines whether or not to receive a request from the communication partner (step S908). When the request from the communication partner is received, the user terminal transmits a response indicating that the P2P connection has been established to the transmission source information described in the header included in the request message (step S909). Thereby, a mutual communication path is established. Therefore, after that, the user terminal transmits data for P2P communication to the transmission source information described in the header (step S918).

  If the request from the communication partner cannot be received in step S908, the user terminal proceeds to the operation of step S914. In step S914, the user terminal switches the P2P communication method to the P2P server route method or the STUN method.

  In P2P communication after step S910, a global IP address is required. In step S910, the user terminal searches for the global IP address in the order of local address information, WAN address information, and global address information. When the global IP address is found, addressed to the address information corresponding to the global IP address (the global IP address) A P2P connection request is transmitted to the IP address and port number).

  When the local IP address matches the global IP address, the user terminal is directly connected to the Internet network without a router.

  After step S910, the user terminal determines whether a response is received from the communication partner that is the transmission destination of the P2P connection request (step S911). When a response from the communication partner is received, a mutual communication path is established. Therefore, after that, the user terminal transmits data for P2P communication to the address information corresponding to the global IP address (step S919).

  On the other hand, when the response from the communication partner cannot be received, the user terminal determines whether or not to receive a request from the communication partner (step S912). When the request from the communication partner is received, the user terminal transmits a response indicating that the P2P connection has been established to the transmission source information described in the header included in the request message (step S913). Thereby, a mutual communication path is established. Therefore, after that, the user terminal transmits data for P2P communication to the transmission source information described in the header (step S920).

  In step S912, when the request from the communication partner cannot be received, the user terminal proceeds to the operation of step S914 and switches the P2P communication method.

  In the procedure shown in FIG. 11A and FIG. 11B, the communication path connection request is tried in the order of the local address information of the communication partner and the WAN address information (see steps S902 and S906). In general, sub-network identification address information and user terminal local address information are allocated by individual routers. Accordingly, there may be a plurality of user terminals having the same local address information not only for IP addresses but also for port numbers between different sub-networks. In step S902, when the local address information is the destination, a communication path connection request message may reach a user terminal other than the desired communication partner. However, user terminals other than the desired communication partner do not exchange address information in advance. Therefore, a user terminal other than the desired communication partner can recognize that the message has arrived in error. Therefore, user terminals other than the desired communication partner do not return a communication path connection response message. Therefore, an erroneous communication path connection does not occur.

  In this way, in the operation shown in FIG. 11, the user terminal transmits a P2P connection request with one of the address information as the destination among the global address information of the communication partner, the WAN side address information, and the local address information. The communication is attempted (see steps S902, S906, or S910), and it is determined whether or not P2P communication is started using the address information. When a response is returned from the communication partner user terminal (see YES in steps S903, S907, and S911), the user terminal determines to start P2P communication using the address information used as the destination (steps S915 and S917). , S919).

  Characteristically, the user terminal determines whether the global IP address matches (see step S901). If the global IP addresses match, the user terminal transmits a P2P connection request to address information corresponding to the global IP address (step S901). If the response from the communication partner is returned (see YES in step S911), it is determined that the P2P communication is started using the address information used as the destination. On the other hand, if the global IP addresses do not match, a P2P connection request is transmitted with one of the address information on the WAN side and local address information of the communication partner as the destination (see steps S902 and S906), and the communication partner If the response from the server is returned (see YES in steps S903 and S907), it is determined that the P2P communication is started using the address information used as the destination.

  When the user terminal receives a P2P connection request from the user terminal of the communication partner (see YES in steps S904, S908, and S912), the user terminal starts P2P communication using the source address information of the P2P connection request. to decide. Then, the user terminal starts P2P communication using the source address information (steps S905, S909, S913, S916, S918, and S920).

  Furthermore, when the user terminal determines that the P2P communication is not started using any one of the address information or the source address information as a result of the determination as described above, the user terminal switches the P2P communication method.

  Next, a flow when P2P communication is performed between the user terminals 1a to 1e illustrated in FIG. 1 will be described with reference to address information.

  FIG. 14A is a diagram illustrating an example of the content of a communication start request message transmitted from the user terminal 1a to the user terminal 1d. FIG. 14B is a diagram illustrating an example of the content of a communication start response message transmitted from the user terminal 1d to the user terminal 1a.

  Since the user terminal 1a and the user terminal 1d exist under the router 2C, the global IP addresses are the same. Accordingly, in step S902, the user terminal 1a transmits a P2P connection request to the local address information of the user terminal 1d (the local IP address is “192.168.1.10” and the port number is “3001”) ( Step S902). As shown in FIG. 1A, the user terminal 1d is not located under the router 2A. Therefore, the request of the user terminal 1a using the local address information does not reach the user terminal 1d. Accordingly, the user terminal 1a does not receive a response from the user terminal 1d (see NO in step S903), and thus proceeds to the operation of step S904.

  Here, it is assumed that the request from the user terminal 1d has not been transmitted to the user terminal 1a (see NO in step S904). In this case, the user terminal 1a transmits a P2P connection request to the WAN side address information of the user terminal 1d (the WAN side IP address is “192.168.10.4” and the port number is “4001”) (step (See S906). The request passes through the router 2A and reaches the router 2B. The router 2B transmits the request to the user terminal 1d according to the set static NAT. Therefore, the user terminal 1d can return a response to the request to the user terminal 1a. Thereafter, the user terminal 1a receives the response from the user terminal 1d (see YES in step S907), and thus starts P2P communication with the user terminal 1d using the WAN side address information (see step S917).

  In this case, the user terminal 1d starts P2P communication with the user terminal 1a using the source address information described in the header of the P2P connection request from the user terminal 1a. In addition, also when the user terminal 1d is a transmission side, the user terminal 1d and the user terminal 1a can perform P2P communication similarly.

  FIG. 15A is a diagram illustrating an example of the content of a communication start request message transmitted from the user terminal 1a to the user terminal 1b. FIG. 15B is a diagram illustrating an example of the content of a communication start response message transmitted from the user terminal 1b to the user terminal 1a.

  Since the user terminal 1a and the user terminal 1b exist under the router 2C, the global IP addresses are the same. Accordingly, in step S902, the user terminal 1a transmits a P2P connection request to the local address information of the user terminal 1b (the local IP address is “192.168.0.101” and the port number is “3021”). As shown in FIG. 1A, the user terminal 1b is located under the router 2A. Therefore, the request of the user terminal 1a using the local address information reaches the user terminal 1b. Therefore, the user terminal 1a performs P2P communication with the user terminal 1b using the local address information (see step S915). In this case, the user terminal 1b starts P2P communication with the user terminal 1a using the source address information described in the header of the request. In addition, also when the user terminal 1b is a transmission side, the user terminal 1b and the user terminal 1a can perform P2P communication similarly.

  FIG. 16A is a diagram illustrating an example of the content of a communication start request message transmitted from the user terminal 1a to the user terminal 1c. FIG. 16B is a diagram illustrating an example of the content of a communication start response message transmitted from the user terminal 1c to the user terminal 1a.

  Since the user terminal 1a and the user terminal 1c exist under the router 2C, the global IP addresses are the same. Accordingly, in step S902, the user terminal 1a transmits a P2P connection request to the local address information of the user terminal 1c (the local IP address is “192.168.10.2” and the port number is “3031”). As shown in FIG. 1A, the user terminal 1c is connected to an upper router (WAN side) router 2C of the router 2A to which the user terminal 1a is connected. Therefore, the P2P connection request of the user terminal 1a using the local address information reaches the user terminal 1c. Therefore, the user terminal 1c can receive this request and start P2P communication.

  In this example, since the NAT setting is performed in the upper router of the user terminal 1a, even when the user terminal 1c transmits a P2P connection request using the WAN side address information of the user terminal 1a, the P2P request is not The user terminal 1a is reached. Therefore, it is also possible to perform P2P communication by transmitting a P2P connection request from the user terminal 1c side.

  FIG. 17A is a diagram illustrating an example of the content of a communication start request message transmitted from the user terminal 1a to the user terminal 1e. FIG. 17B is a diagram illustrating an example of the content of a communication start response message transmitted from the user terminal 1e to the user terminal 1a.

  The user terminal 1a is located under the router 2C, and the user terminal 1e is located under the router 2D. Therefore, the global IP address does not match. Therefore, the user terminal 1a transmits a P2P connection request to address information corresponding to the global IP address in the process of step S910. Here, the user terminal 1a transmits the request to the WAN side address information (WAN side IP address “133.121.2.15” and port number “4021”) of the user terminal 1e. Thereafter, when a response from the user terminal 1e is returned (see YES in step S911), the user terminal 1a starts P2P communication with the user terminal 1e using the address information (see step S919). The user terminal 1e performs P2P communication with the user terminal 1a using the source address information described in the header of the request. In addition, when the user terminal 1e is a transmission side, the user terminal 1e performs P2P communication with the user terminal 1a using the global address information of the user terminal 1a as address information corresponding to the global address information of the user terminal 1a.

  Note that the user terminal 1e may check the address information received from the user terminal 1a to determine whether or not the WAN-side IP address and the global IP address do not match. If they do not match, the user terminal 1e determines that there is a router that is not NAT-configured, and determines that no response is made even if a P2P connection request is transmitted to the user terminal 1a. In this case, the user terminal 1e may wait for a P2P connection request from the user terminal 1a for a certain time, and may not transmit a P2P connection request by itself. In the example of FIG. 17A and FIG. 17B, even when controlled as described above, a P2P connection request from the user terminal 1a to the user terminal 1e can be transmitted, so the communication path between the user terminal 1a and the user terminal 1e Is established.

  Hereinafter, a specific processing flow until P2P communication is realized between two user terminals will be described.

  18A and 18B are diagrams illustrating a specific communication sequence for performing P2P communication between the user terminal 1a and the user terminal 1d. In this example, it is assumed that router B does not support UPnP, and that router B cannot perform static NAT setting. Assume that the IP addresses set for the user terminal 1a, the router 2A, the router 2C, the router 2B, and the user terminal 1d are the same as those shown in FIGS. 3A and 3B.

  First, the user terminal 1a and the user terminal 1d each communicate with the P2P server 3 to register identification information (P0, see FIG. 5). For this purpose, for example, the user terminals 1a and 1d and the P2P server 3 execute a TCP session.

  Next, the user terminal 1a transmits and receives its own global address information (132.152.12) from the P2P server 3 by transmitting and receiving an address information notification request message M11 (see FIG. 8A) and an address information notification response message M12 (see FIG. 8B). 6.50: 6001) is acquired (see P1, step S501 in FIG. 7). In this process, the routers 2A and 2C between the P2P server 3 and the user terminal 1a perform dynamic NAT setting.

  Next, the user terminal 1a performs static NAT setting on the router 2A immediately above (see P2, step S502 in FIG. 7). Here, (162.168.100: 2701) is converted to (192.168.10.5:5001), and (192.168.10.5:5001) is converted to (162.0.10.100). : 2701), the static NAT setting is converted.

  Next, the user terminal 1a transmits a communication start request message (see FIG. 9A) to the user terminal 1d via the P2P server 3 (see P3, step S504 in FIG. 7). At this time, the user terminal 1a notifies the address information start request message including global address information, WAN address information, and local address information, which are address information about itself.

  Next, the P2P server 3 transfers a communication start request message from the user terminal 1a to the user terminal 1d (see P4, step S505 in FIG. 7).

  Next, when receiving the communication start request message, the user terminal 1d transmits and receives its own global address information (133) by transmitting and receiving an address information notification request message M51 (see FIG. 8A) and an address information notification response message M52 (see FIG. 8B). .15.2.6.50: 6003) is acquired from the P2P server 3 (see P5, step S603 in FIG. 10).

  Thereafter, the user terminal 1d tries to perform static NAT setting by UPnP for the router 2B directly above (see P6, step S603 in FIG. 10). However, since the router 2B does not support UPnP, static NAT cannot be set. Therefore, the user terminal 1d cannot appropriately execute the processes of steps S603 and S604 in FIG. 10 and cannot acquire WAN address information.

  Then, it progresses to description of FIG. 18B. The user terminal 1d transmits a communication start response message (see FIG. 9B) to the user terminal 1a via the P2P server 3 (see P7, step S605 in FIG. 10). At this time, the user terminal 1d includes global address information, WAN address information, and local address information, which are address information about itself, in an address information start request message and notifies the user terminal 1d. However, since static NAT is not set, the WAN address information is blank.

  Next, the P2P server 3 transfers a communication start response message from the user terminal 1d to the user terminal 1a (P8, see step S606 in FIG. 10).

  Through the processing up to P8, the user terminal 1a and the user terminal 1d have acquired the mutual address information.

  Next, the user terminal 1a transmits a P2P connection request addressed to the local address information (192.168.1.10:3001) of the user terminal 1d (see P9, step S902 in FIG. 11A). However, the packet is discarded due to reasons such as no destination path information and no destination.

  At the same time, the user terminal 1d transmits a P2P connection request addressed to the local address information (192.168.0.100: 2701) of the user terminal 1a (P10, step S902 in FIG. 11A). However, here too, the packet is discarded because there is no destination route information or there is no destination.

  Therefore, the user terminal 1d transmits a connection request to the WAN side address information (192.168.10.5:5001) on the user terminal 1a side (see P11, step S906 in FIG. 11A). At this time, the router 2B changes from (192.168.10.4:6551) to (192.168.1.10:3001) and from (192.168.1.10:3001) to (192.168.10). .4: 6551). The dynamic NAT2 at this time is different from the dynamic NAT1 in P5.

  Since the connection request from the user terminal 1d does not come out to the WAN side of the router 2C, the NAT of the router 2C is not executed and reaches the router 2A (P12).

  The router 2A transfers the connection request message from the user terminal 1d to the user terminal 1a using the static NAT route set in P2 (P13). Therefore, the user terminal 1a receives the connection request from the user terminal 1d with the port number “2701” (see P14, step S904 in FIG. 11A).

  Next, the user terminal 1a transmits a connection response message to the source address information (192.168.10.4:6551) of the received connection request (P15, step S905 in FIG. 11A). The message arrives at the user terminal 1d via the static NAT of the router A and the dynamic NAT2 of the router B, which are paths through which the connection request message has arrived (P16). The user terminal 1d receives the connection response at the port number 3001 (P17). Thereafter, the user terminal 1a and the user terminal 1d perform P2P communication with each other via the static NAT and the dynamic NAT2.

  As described above, according to the first embodiment, global address information, WAN side address information, and local address information are exchanged between user terminals, and P2P communication is started using one of the address information as appropriate. When there is a request from the communication partner, P2P communication is started using the source address information described in the request. Accordingly, a communication apparatus, method, and program capable of realizing P2P communication even in a communication environment in which a network is configured in a complicated manner are provided. Furthermore, even if the network configuration changes dynamically, P2P communication is performed based on the newly exchanged global address information, WAN side address information, and local address information. Therefore, a communication apparatus, method, and program capable of realizing P2P communication even when the network configuration dynamically changes are provided. If P2P communication is impossible using any address information, the user terminal switches the communication method to P2P communication via the P2P server or P2P communication by the STUN communication method.

  The user terminal according to the present invention determines a method capable of P2P communication based on the first and second global address information, WAN side address information, and local address information exchanged between two user terminals. As this method, a method of starting P2P communication using local address information (see S915 in FIG. 11A), a method of starting P2P communication using WAN address information (see S917 of FIG. 11A), and source address information A method for starting P2P communication using the IP (see S916, S918 in FIG. 11A and S920 in FIG. 11B), a method for starting P2P communication with address information corresponding to the global IP address (see S919 in FIG. 11B), P2P server Is used to start P2P communication (see S914 in FIG. 11B), and PUNP communication is started using the STUN communication method (see S914 in FIG. 11B).

  Note that the user terminal may execute the operation of step S910 after step S908 without executing the determination of step S901. That is, it is not essential to determine whether the global IP addresses match. In the present invention, if P2P communication is attempted using global address information, WAN side address information, and local address information, the order of determination as to whether or not P2P communication is possible is limited to the order shown in FIG. is not.

  The global address information may be only an IP address. When the global address information is only an IP address, the user terminal may not perform the P2P connection specifying the global address information.

  The global address information is not limited to the global IP address and the port number as long as it is information related to an address on the Internet.

  Note that the WAN side address information is not limited to the WAN side IP address and port number as long as it is information related to the address on the WAN side that is assigned to the router immediately above the user terminal.

  Note that the local address information is not limited to the local IP address and the port number as long as it is information related to the address on the local network assigned to the user terminal.

(Second Embodiment)
In the second embodiment, the user terminal communicates with itself in what network configuration or communication path based on its own address information and address information of the communication partner. After determining in advance whether or not it is possible, P2P communication is executed. If there are only two or fewer routers between the user terminal and the Internet, P2P communication can be performed using any destination address, and the second embodiment can almost be determined. Since the network configuration, the identification information registration procedure, and the communication information exchange procedure are the same as those in the first embodiment, description thereof will be omitted. In the figure, the notation (xy) is used. Here, “x” indicates the number of routers existing above itself (the number of router layers). “Y” indicates the number of routers (number of router layers) existing above the user terminal of the communication partner. The symbol “?” Indicates a case where it is not possible to determine whether the hierarchy is one or two, or when the hierarchy is unknown. Also in the second embodiment, the user terminal implements the operation described below by executing the P2P communication program.

  FIG. 19A and FIG. 19B are flowcharts showing the operation of the user terminal in the second embodiment. Hereinafter, the operation of the user terminal in the second embodiment will be described with reference to FIGS. 19A and 19B. The operations shown in FIGS. 19A and 19B are realized by the used address information determination unit 107 and the P2P communication processing unit 108. In describing the operation of the user terminal with reference to FIGS. 19A and 19B, it is assumed that there are no more than two routers between the user terminal and the Internet. However, as will be described later, the second embodiment can also be used when there are three or more routers between the user terminal and the Internet.

  The user terminal compares the communication start request message sent from itself to the communication partner and the communication start response message obtained from the communication partner via the P2P server 3, and executes the following procedure.

  First, the user terminal determines whether or not its own global IP address matches the global IP address of the communication partner (step S1000). If the global IP addresses do not match, the user terminal and the communication partner communicate via the Internet network, so the user terminal proceeds to the process shown in FIG. 19B. On the other hand, if the global IP addresses match, the communication with the communication partner is under the same router, and the operation proceeds to step S1001. Here, the case where the global IP addresses do not match indicates that the communication device is connected to the communication partner via the Internet. This is called the first type. On the other hand, the case where the global IP addresses do not match is called the second type. In the figure, the type number is shown.

  In step S <b> 1001, the user terminal determines whether or not a static NAT setting is performed in the router immediately above the communication partner. Specifically, the user terminal refers to the address information of the communication partner and determines that the static NAT setting is performed when the WAN-side address information is set. When static NAT setting is performed, the user terminal proceeds to the operation of step S1002. On the other hand, when the static NAT setting is not performed, the user terminal cannot determine how many routers exist on the communication partner. In this case, the user terminal proceeds to the operation of step S1006. Here, a case where a static NAT can be set for a router directly above a communication partner user terminal is referred to as a third type. A case in which a static NAT cannot be set for a router immediately above a communication partner user terminal is referred to as a fourth type.

  In step S1002, the user terminal determines whether there are two layers of routers on the communication partner. Specifically, the user terminal refers to the address information of the communication partner and compares the global IP address with the WAN side IP address. If the global IP address matches the WAN-side IP address, the user terminal determines that one layer of router exists on the communication partner. On the other hand, when the global IP address does not match the WAN side IP address, the user terminal determines that there are two layers of routers on the communication partner. If there are two layers of routers on the communication partner, the user terminal proceeds to the operation of step S1003. On the other hand, if there is only one layer of router on the communication partner, the user terminal proceeds to the operation of step S1005. Here, the case where there is only one router from the communication partner user terminal to the Internet is called the fifth type. The case where there are two routers from the user terminal of the communication partner to the Internet is called the sixth type.

  In step S1003, the user terminal determines whether or not the WAN side IP address included in its own address information matches the WAN side IP address included in the address information of the communication partner. If the WAN-side IP addresses match, it means that the router immediately above itself and the router immediately above the communication partner are the same. Therefore, a two-layer router exists on itself. If the WAN side IP addresses match, the user terminal proceeds to the operation of step S1005. On the other hand, if the WAN-side IP addresses do not match, it means that the router directly above itself and the router immediately above the communication partner are not the same. Therefore, it is unknown how many routers exist on itself. If the WAN side IP addresses do not match, the user terminal proceeds to the operation of step S1004. Here, the case where the WAN side IP addresses match is referred to as a seventh type. The case where the WAN side IP addresses do not match is referred to as an eighth type.

  In step S1004, that is, when the address information belongs to the second, third, sixth, and eighth types, the user terminal establishes a communication path connection to the WAN address information (IP address and port number) of the communication partner. Request. The communication path connection request message may be a well-known one. The communication partner transmits a response to the source address information described in the header of the received communication path connection request message. Even if static NAT is not set in the router above itself, dynamic NAT is set by communication from itself to the communication partner. Therefore, the communication path connection response message returned from the communication partner reaches the user terminal itself by following the communication path by the dynamic NAT. Therefore, P2P communication can be realized between itself and the communication partner.

  The case where the P2P communication shown in step S1004 is performed is, for example, a case where a communication path is connected from the user terminal 1a to the user terminal 1d between the user terminal 1a shown in FIG. 14A and the user terminal 1d shown in FIG. 14B. . In addition, the communication path connection from the user terminal 1c shown in FIG. 16B to the user terminal 1a shown in FIG. 16A, or the communication path connection from the user terminal 1c shown in FIG. 1 to the user terminal 1d shown in FIG. .

  In step S1005, that is, when the address information belongs to the second, third, and fifth types, or when the address information belongs to the second, third, sixth, and seventh types, the user terminal Request communication path connection to local address information of communication partner. In response to this, the communication partner transmits a response to the source address information described in the header of the received communication path connection request message. Thereby, P2P communication between itself and a communication partner is realized. The communication path connection request message is communication within the same sub-network, or the communication partner is connected to the router of the higher level (WAN side) of the communication partner. Can receive a reply. However, in the case where there are routers exceeding two layers in step S1005, the case where the communication partner and the communication partner are not under the same router may occur. In this case, P2P communication fails in the procedure of step S1005. In this case, the user terminals are connected by a method such as switching the P2P communication connection method and relaying communication data with a P2P server.

  The case where the P2P communication shown in step S1005 is performed corresponds to, for example, communication path connection from the user terminal 1a shown in FIG. 16A to the user terminal 1c shown in FIG. 16B. In addition, the communication path connection from the user terminal b shown in FIG. 1A to the user terminal c shown in FIG. 1A and the communication path connection from the user terminal d shown in FIG. 1A to the user terminal c shown in FIG. 1A correspond to this case. .

  In step S <b> 1006, the user terminal determines whether or not a static NAT setting has been performed for the router immediately above itself. Specifically, if the WAN side IP address is described in the address information, the user terminal determines that static NAT setting has been performed. Here, the case where the router directly above the own device can be set to static NAT is referred to as a ninth type. On the other hand, a case where a router directly above the own device cannot set static NAT is called a tenth type.

  If it is determined in step S1006 that static NAT setting has been performed, a message transmitted from the first user terminal (hereinafter simply referred to as the first user terminal) as its own device is the communication partner. The second user terminal (hereinafter simply referred to as the second user terminal) cannot receive, but the first user terminal can receive a message from the second user terminal. Therefore, the first user terminal proceeds to the operation of step S1007 and waits for a communication path connection request from the second user terminal. Since the second user terminal determines that the router immediately above the first user terminal is performing static NAT setting, the operation of step S1004 or step S1005 is performed. Therefore, the second user terminal makes a communication path connection request to the first user terminal. Therefore, P2P communication is possible. The operation in step S1007 is performed when the address information belongs to the second, fourth, and ninth types.

  If it is determined in step S1006 that static NAT setting is not performed, it is not known whether the number of upper routers is one or two for both the first and second user terminals. However, the first user terminal and the second user terminal may be located in the same subnetwork. Therefore, the first user terminal requests communication path connection to the local address information of the second user terminal (step S1008). The operation in step S1008 is performed when the address information belongs to the second, fourth, and tenth types.

  When the first and second user terminals are located in the same sub-network, or when the second user terminal is connected to the router to which the upper level (WAN side) of the router to which the first user terminal is connected is connected When connected (for example, the relationship between the user terminal 1a and the user terminal 1c), a message from the first user terminal reaches the second user terminal by dynamic NAT setting.

  Even in the above case, when static NAT is not set in each router (when UPnP is not supported), it is impossible to determine the connection relationship between the two. In step S1001, NO is determined, and the operation of step S1008 is executed instead of the operation of step S1007.

  On the other hand, if communication cannot be performed in step S1008, the second user terminal may request a P2P connection to the local address information of the first user terminal. By controlling in this way, P2P communication can be performed if the first user terminal is connected to a router connected to a higher level (WAN side) of the router to which the second user terminal is connected. Become.

  After step S1008, the first user terminal determines whether a communication path has been established (step S1009). When the communication path is established, the first and second user terminals subsequently perform P2P communication using the established communication path. On the other hand, when the communication path is not established, there are two routers upstream like the user terminals 1a and 1d, and static NAT is not set in the routers 2A and 2B directly above. In this case, the first user terminal performs P2P communication with the second user terminal by switching the P2P communication method to one or both of the P2P server route method and the STUN method (step S1010).

  Even when static NAT setting is performed for the first user terminal in step S1006, there may be only one upper router of the communication partner as in the user terminal 1c. Accordingly, the first user terminal may proceed to step S1007 when a communication path cannot be established after attempting a communication start request from itself, as in steps S1008 and S1009.

  In step S1100 of FIG. 19B, the first user terminal determines whether or not static NAT setting is performed on the router immediately above the second user terminal. The determination criteria are the same as in step S1001. When static NAT setting is performed in the router immediately above the second user terminal, the first user terminal proceeds to the operation of step S1101. On the other hand, when the static NAT setting is not performed in the router immediately above the second user terminal, the first user terminal proceeds to the operation of step S1108.

  In step S <b> 1101, the first user terminal determines whether or not a static NAT setting is performed on the router immediately above. Specifically, the first user terminal refers to the address information of the own device, and determines that the static NAT setting is performed when the WAN-side address information is set. When static NAT setting is not performed, the first user terminal proceeds to the operation of step S1103. On the other hand, when the static NAT setting is performed, the first user terminal proceeds to the operation of step S1102. Here, the case where the router present immediately above the own device is capable of static NAT is referred to as a ninth type. On the other hand, a case where a router directly above the own device cannot set a static NAT is called a tenth type.

  In step S1102, the first user terminal determines whether or not the router on the own device has two layers. Specifically, the first user terminal refers to its own address information and compares the global IP address with the WAN side IP address. When the global IP address matches the WAN-side IP address, the user terminal determines that there is one layer of router on its own device. On the other hand, when the global IP address does not match the WAN side IP address, the user terminal determines that there are two layers of routers on the communication partner. If the router has two layers, the first user terminal proceeds to the operation of step S1103. On the other hand, if the router is not two layers, that is, if the router is one layer, the first user terminal proceeds to the operation of step S1104. Here, the case where there is only one router from its own device to the Internet is called the eleventh type. A case where there are two routers from the own device to the Internet is called a twelfth type.

  In step S1104, the first user terminal determines whether the router above the second user terminal has two layers. If the router above the second user terminal has two layers, the first user terminal proceeds to the operation of step S1105. On the other hand, when the router above the second user terminal is not in the second layer, that is, in the first layer, the first user terminal proceeds to the operation of step S1106.

  In step S1103, the first user terminal determines whether the router above the second user terminal has two layers. If the router above the second user terminal is not the second layer, the first user terminal proceeds to step S1106. On the other hand, when the router above the second user terminal has two layers, the first user terminal proceeds to the operation of step S1107.

  The condition for executing the operation of step S1105 is that static NAT setting is performed in the router immediately above the first and second user terminals (the third and ninth types), and the first user terminal Is the first layer (the eleventh type) and the second router above the second user terminal is the second layer (sixth tie). For example, in the example of FIG. 1A, the first user terminal is the user terminal 1e, and the second user terminal is the user terminal 1a. When a two-layer router exists on the second user terminal, the second user terminal cannot perform static NAT setting of a router above the router immediately above. Therefore, the communication path connection request message from the first user terminal to the second user terminal does not arrive. On the other hand, since the router above the first user terminal has a single layer and the router has a static NAT setting, a communication path connection request from the second user terminal to the first user terminal is requested. The message reaches the first user terminal. Therefore, the first user terminal waits for a communication path connection request from the second user terminal (step S1105). In such a condition, the second user terminal performs an operation in step S1106 described later. In step S1106, the second user terminal transmits a communication path connection request based on the WAN address information of the first user terminal. In the operation of step S1106, since the router existing on the second user terminal is one layer, the IP address of the WAN address information matches the IP address of the global address information.

  There are three conditions under which the operation of step S1106 is executed. First, static NAT is set in the router immediately above the first and second user terminals (third and ninth types), and the router is only one layer above the first user terminal. This is a case in which there is only one layer on the second user terminal (fifth type) (fifth type). Second, the static NAT setting is performed in the router immediately above the second user terminal (third type), and the static NAT setting is not performed in the router immediately above the first user terminal. (Tenth type) is a case where only one layer of router exists on the second user terminal (fifth type). Third, static NAT is set in the router directly above the first and second user terminals (third and ninth types), and there are two layers of routers on the first user terminal. However, this is a case where only one layer of router exists on the second user terminal (fifth type). In this case, the first user terminal transmits a communication path connection request to the second user terminal using the WAN side address information of the second user terminal (step S1106). In step S1106, since the router has only one layer on the second user terminal, the IP address of the WAN side address information matches the IP address of the global address information. Accordingly, since the second user terminal can respond based on the transmission source information of the request, communication for P2P communication between the first user terminal and the second user terminal. The road is established.

  In step S1108, the first user terminal determines whether or not static NAT setting is performed in the router immediately above the first user terminal. When static NAT setting is performed, the first user terminal proceeds to the operation of step S1109. On the other hand, when the static NAT setting is not performed, the first user terminal proceeds to the operation of step S1107.

  In step S1109, the first user terminal determines whether or not the router existing on the first user terminal has two layers. If there are two layers, the first user terminal proceeds to the operation of step S1107. On the other hand, if it is not the second layer, the first user terminal proceeds to the operation of step S1110.

  There are four conditions for executing the operation of step S1107.

  First, static NAT is set in the router immediately above the first and second user terminals (third and ninth types), and two layers of routers exist on the first user terminal. (The twelfth type), and the router existing on the second user terminal has two layers (sixth type). In the first case, there is one layer of router that cannot set static NAT on the first and second user terminals. Therefore, the communication path connection request message from the first user terminal and the communication path connection request message from the second user terminal do not reach each other. Therefore, the first user terminal executes the operation of step S1107.

  Second, static NAT setting is performed in the router immediately above the second user terminal (third type), and static NAT setting is not performed in the router immediately above the first user terminal. This is a case where the router existing on the second user terminal has two layers (sixth type) (sixth type). In the second case, since there is a router that is not set to static NAT on the second user terminal, the communication path connection request message from the first user terminal does not reach the second user terminal. In addition, since static NAT setting is not performed in the router immediately above the first user terminal, a communication path connection request message from the second user terminal does not reach the first user terminal. Therefore, the first user terminal executes the operation of step S1107.

  Third, static NAT setting is not performed in the router immediately above the second user terminal (fourth type), and static NAT setting is not performed in the router immediately above the first user terminal. No (tenth type). In the third case, since the static NAT setting is not performed in the first and second routers, the communication path connection request messages from the first and second user terminals cannot be received from each other. Therefore, the first user terminal proceeds to the operation of step S1107. The third condition indicates a case as shown in FIGS. 12A and 12B, for example.

  Fourth, static NAT setting is not performed in the router immediately above the second user terminal (fourth type), and static NAT setting is performed in the router immediately above the first user terminal. (Ninth type) is a case where the router existing on the first user terminal has two layers (the twelfth type). In the fourth case, since there is a router that cannot perform static NAT setting on the first user terminal, the communication path connection request message from the second user terminal is the first user terminal. It does not reach the terminal. Moreover, since static NAT setting is not performed in the router immediately above the second user terminal, the communication path connection request message from the first user terminal does not reach the second user terminal. Therefore, the first user terminal executes the operation of step S1107.

  When there is a router for which static NAT cannot be set as in the first to fourth cases, the communication path can only be established by dynamic NAT setting, but the communication path is established by dynamic NAT setting. To do this, a message from one side must reach the other. In the first to fourth cases, since the messages from both cannot be received from each other, the communication path cannot be established even by dynamic NAT setting. Therefore, in step S1107, the first communication terminal performs P2P communication with the second user terminal by switching to one or both of the P2P server route method and the STUN method.

  The condition for executing the operation in step S1100 is that static NAT setting is not performed in the router immediately above the second user terminal (fourth type), and static is set in the router immediately above the first user terminal. This is a case where NAT setting has been performed (9th type) and there is only one router on the first user terminal (11th type). In this case, since the static NAT setting is not performed in the router immediately above the second user terminal, the communication path connection request message from the first user terminal does not reach the second user terminal. However, since the router existing on the first user terminal is one layer and static NAT setting is performed for the router, the second user terminal performs communication by executing the operation of step S1106. The road connection request message can be delivered to the first user terminal. Therefore, the first user terminal waits for a communication path connection request message from the second user terminal (step S1100). As a result, P2P communication is realized.

  In the above description, the first and second user terminals are both user terminals having the procedure shown in FIGS. 19A and 19B. When the second user terminal does not have the procedure shown in FIGS. 19A and 19B, the second user terminal may not be able to receive the communication path connection request message transmitted from the first user terminal. In this case, the second user terminal does not transmit a communication path connection response message. In addition, the second user terminal may not transmit a communication path connection request message. In preparation for such a case, immediately before the end of FIGS. 19A and 19B, the first user terminal can establish a communication path with the second user terminal as in step S1009, for example. If it is not established, for example, an operation for switching to one or both of the P2P server method and the STUN method may be performed as in step S1010.

  In step S1005 and step S1008 of FIG. 19A, the first user terminal tries to make a communication path connection request to the local address information of the second user terminal. The local IP address information of the user terminal is allocated by each router. Accordingly, there may be a plurality of user terminals having the same local IP address information in different sub-networks. Therefore, when the local address information is the destination, a communication path connection request message may reach a user terminal other than the desired communication partner. However, since the user terminal other than the desired communication partner has not exchanged communication information in advance, it can be seen that the message has arrived in error. Therefore, user terminals other than the desired communication partner do not return a communication path connection response message. Therefore, an erroneous communication path connection does not occur.

  When the user terminal is directly connected to the Internet network, that is, when the global IP address matches the local IP address, the local address information is described in the WAN side address information column of the upper router. Therefore, after step S1104 or step S1103, the first user terminal judges as if the upper router is one layer. In this case, the first user terminal proceeds to the operation of Step S1106, and makes a communication path connection request with the destination WAN address information as the destination. However, the operation of step S1106 in this case is substantially the same as the operation of applying the other party's local address information as a direct destination.

  As described above, according to the second embodiment, the user terminal belongs to any type among the types in which the first and second global address information and the first and second WAN side address information are predetermined. Determine whether or not. Depending on the type to which the first and second global address information and the first and second WAN side address information belong, the user terminal sets the destination address information to the second global address information, Whether to use WAN side address information or second local address information is determined in advance. Further, the user terminal waits for a connection request from the user terminal of the communication partner or the communication method according to the type to which the first and second global address information and the first and second WAN side address information belong. Is determined in advance. Then, the user terminal starts P2P communication using the first and second global address information and the address information corresponding to the type to which the first and second WAN side address information belongs. The combinations of the first to twelfth types shown in the second embodiment cover all cases where the number of routers existing on the user terminal is two or less. Therefore, according to the procedure shown in the second embodiment, the user terminal predicts a communication path with the communication partner and determines in advance what address information should be used to start P2P communication. can do. Therefore, the user terminal according to the second embodiment can reduce the number of trials for transmitting a communication path connection request message, and can reduce transmission of useless communication path connection request messages. As a result, establishment of a communication path can be accelerated.

  Also in the second embodiment, as in the first embodiment, the user terminal uses a method capable of P2P communication based on the first and second global address information, the WAN side address information, and the local address information. to decide. As the method, a method of starting P2P communication using local address information (see S1005 and S1008 in FIG. 19A), a method of starting P2P communication using WAN side address information (S1004 of FIG. 19A, and FIG. 19B). S1106), a method of starting P2P communication using source address information (see S1007 in FIG. 19A, S1105 and S1110 in FIG. 19B), and a method of starting P2P communication with address information corresponding to the global IP address (see FIG. 19B) (see S1106 in FIG. 19B), a method for starting P2P communication using a P2P server (see S1010 and S1107 in FIG. 19A), and a method for starting P2P communication using a STUN communication method (S1010 in FIG. 19A and FIG. 14B). S1107).

  The present invention can also be applied to a case where there are three or more routers between any user terminal and the Internet. Hereinafter, a network having three or more routers between any user terminal and the Internet will be considered.

  Even when there are three or more routers between the user terminal and the Internet, it is assumed that the first and second user terminals operate according to the procedure shown in FIGS. 19A and 19B.

  First, it is assumed that the first and second user terminals are located from an arbitrary router in the network to a router two lower. In this case, since the two global IP addresses match, the first and second user terminals attempt P2P communication according to the procedure of FIG. 19A. The arbitrary router corresponds to the uppermost router when there are no more than two routers between the user terminal and the Internet. Therefore, in this case, the first and second user terminals can start P2P communication by operating according to the procedure shown in FIG. 19A.

  Next, there are three or more routers between one user terminal of the first and second user terminals and the Internet, and two or less routers exist between the other user terminal and the Internet. Assume that there was. In this case, since the two global IP addresses do not match, the first and second user terminals attempt P2P communication according to the procedure of FIG. 19B. Assume that the other user terminal is the second user terminal. When static NAT setting is performed in the router immediately above the second user terminal, the first user terminal proceeds to the operation of step S1103. If there is only one router on the second user terminal, the first user terminal proceeds to the operation of step S1106 and starts P2P communication using the global address information of the second user terminal. On the other hand, when there are two routers on the second user terminal, the first user terminal proceeds to the operation of step S1107 and switches the communication method. Therefore, the first and second user terminals can start P2P communication.

  When there are three or more routers between any one of the first and second user terminals and the Internet, there are other connection relationships that are assumed. Therefore, when the procedure shown in FIGS. 19A and 19B is followed, there may be a case where P2P communication is impossible. Therefore, the user terminal determines whether or not a communication path with the communication partner has been established before the end of FIGS. 19A and 19B, and if not established, the P2P communication method is changed to the P2P server route method or the STUN method. It is better to switch to. As a result, P2P communication is possible even when there are three or more routers between the user terminal and the Internet.

  As described above, when two user terminals are connected via four or less routers, if the router immediately above one user terminal can perform static NAT setting corresponding to UPnP, the other user terminal To start P2P communication.

  As described above, when two user terminals are separated by five or more routers, there is a router that cannot perform static NAT setting, or static NAT setting cannot be performed even if static NAT setting is attempted. There may be a case where a message from a communication partner does not arrive or a message that is not addressed to itself due to a router existing in the middle. Therefore, considering the possibility that the network to which the user terminal belongs is a large-scale network, the user terminal determines whether or not communication was possible within a predetermined time, and step S1010 if communication was not possible. A step of trying the P2P server route method and / or the STUN method as in step S1107 may be provided before the end of FIGS. 19A and 19B.

  Note that the determination procedure in the flowcharts of FIGS. 19A and 19B is merely an example. The method of defining the types to which the first and second global address information and the first and second WAN side address information belong is only an example. If the user terminal can know the connection state between the device and the communication partner, what address information should the user terminal use to start P2P communication in a procedure other than the determination procedure shown in FIGS. 19A and 19B? You may judge. The determination procedure for this can be applied to this embodiment as long as it is a procedure that can completely or partially infer the connection state of the network.

  As described above, in the first and second embodiments, the steps of acquiring global address information assigned to the user terminal using a server on the Internet, such as step S501 and step S602, and step S503, A step of setting an address translation rule for the router immediately above from the user terminal as in step S604; a step of acquiring the WAN address of the router immediately above from the user terminal as in step S502 and step S603; As in step S505, step S605, or step S606, the communication partner is notified of WAN address information based on the address translation rule set in the immediately above router, global address information acquired from the server, and local address information. Step a, FIGS. 11,19A, as described in 19B, a P2P communication method characterized by comprising the steps of P2P communication using the notified information. In addition, by providing means for executing each step described in the first and second embodiments, a system that enables P2P communication that directly communicates between user terminals can be configured.

  The user terminal notifies the user terminal of the communication partner of the global address information, the WAN side address information, and the local address information. When the global address information is the same, the P2P communication is performed using the local address information or the WAN side address information. Start. Further, the user terminal compares the notified address information of the communication partner with its own address information, determines whether or not P2P communication is possible using the address information of the communication partner, and determines that it is impossible. In this case, the communication is performed by switching the communication method.

(Third embodiment)
FIG. 20 is a block diagram showing a detailed functional configuration of a communication apparatus which is a user terminal capable of executing the P2P communication method of the present invention. As illustrated in FIG. 20, the communication device includes an identification information recording unit 201, a self / other address information storage unit 202, an address information comparison determination unit 203, a communication path establishment determination unit 204, a control unit 205, and a communication method switching. Unit 206, application processing unit 207, identification information registration transmission unit 208, address information notification request transmission / response reception unit 209, static NAT setting request unit 210, communication start request transmission / response reception unit 211, A communication path connection request transmission / response reception unit 212, a P2P communication processing unit 213, a P2P server route method processing unit 214, a STUN method processing unit 215, and a network interface 216 are provided. Each functional block is coupled as indicated by arrows in FIG.

  The identification information recording unit 201 is a memory that stores identification information of the communication device itself that is a user terminal. The own / other address information storage unit 202 is a memory for storing its own address information and address information of the communication partner as shown in FIGS. 14A and 14B. Address information comparison determination unit 203, communication path establishment determination unit 204, communication method switching unit 206, application processing unit 207, identification information registration transmission unit 208, address information notification request transmission / response reception unit 209, static NAT setting request unit 210 , A communication start request transmission / response reception unit 211, a communication path connection request transmission / response reception unit 212, a P2P communication processing unit 213, a P2P server routed method processing unit 214, a STUN method processing unit 215, and a network interface 216, It is a functional block responsible for the processing described in the first and second embodiments, and executes predetermined processing according to an instruction from the control unit 205. The network interface 216 performs processing in the physical layer and the data link layer, and transmits and receives data to and from the home network and the Internet network.

  The identification information registration transmission unit 208 establishes a communication path with the P2P server 3 for the processing of steps S301 and S302, transmits its identification information in the identification information recording unit 201 to the P2P server, Register with the P2P server 3.

  As described in step S501, the address information notification request transmission / response reception unit 209 creates and transmits an address information notification request message, receives the address information notification response message, and stores the acquired address information in its own address information. It is described in the global address information column of the section 202.

  The address information comparison / determination unit 203 compares the address information as in step S <b> 502 and passes the comparison result to the control unit 205. Based on the comparison result, the control unit 205 causes the static NAT setting request unit 210 to perform static NAT setting for the router immediately above, if necessary. The static NAT setting request unit 210 describes the setting result in the WAN address information column of the own / other address information storage unit 202. The process of the static NAT setting request unit 210 is the process described in step S502 and step S503.

  The communication start request transmission / response reception unit 211 transmits a communication start request message to the P2P server 3 according to step S504. Further, the communication start request transmission / response receiving unit 211 waits for and receives a communication start response message that is a reply to the communication start request message, and when received, stores the address information of the communication partner described in the communication start response message. Stored in the communication partner field of the unit 202. These operating states are monitored by the control unit 205.

  When this communication apparatus is a communication partner of another communication apparatus, the processing described in steps S601 to S605 is performed using the identification information registration transmission unit 208, the address information notification request transmission / response reception unit 209, and the address information comparison determination unit 203. Then, the static NAT setting request unit 210 and the communication start request transmission / response reception unit 211 perform the operation based on an instruction from the control unit 205.

  When the own address information as shown in FIGS. 14A and 14B can be obtained, the communication apparatus shifts to the operation of the P2P communication path connection described with reference to FIG. 11 or FIGS. 19A and 19B.

  The address information comparison / determination unit 203 compares predetermined address information in the own / other address information storage unit 202 in accordance with an instruction from the control unit 205, and determines whether the communication is via the Internet network or communication under the same router. Then, it is determined whether or not the destination is capable of P2P communication, and the determination result is notified to the control unit 205.

  The control unit 205 instructs the communication channel connection request transmission / response reception unit 212 to transmit a communication channel connection request message to the selected address information, and waits for a communication channel connection response message from the communication partner. In the case of a determination result that there is no route for delivering the communication path connection request message from itself to the communication partner, the control unit 205 instructs the communication path connection request transmission / response reception unit 212 to send a communication path from the communication partner. Wait for the connection request message to be received.

  Under the instruction of the control unit 205, the communication path establishment determination unit 204 transmits a communication path connection request message by the communication path connection request transmission / response reception unit 212, receives a corresponding communication path connection response message, and performs communication. The reception of the path connection request message and the transmission of the corresponding communication path connection response message are monitored, whether or not the communication path has been established is determined, and the determination result is notified to the control unit 205. When the transmission of the communication path connection request message and the reception of the corresponding communication path connection response message, or the reception of the communication path connection request message and the transmission of the corresponding communication path connection response message are successful, the communication path establishment determination unit 204 The control unit 205 is notified of the result. The control unit 205 activates the P2P communication processing unit 213, and thereafter, the application processing unit 207 performs P2P communication with the communication partner via the P2P communication processing unit 213.

  If the communication path connection request message cannot be transmitted and the communication path connection request message has not been received, the communication method switching unit 206 determines that P2P communication is not possible and notifies the control unit 205 of the communication method switching request message.

  Upon receiving the notification, the control unit 205 instructs the communication method switching unit 206 to activate the P2P server-based method processing unit 214 or the STUN method processing unit 215 to establish a communication path.

  The process in step S901 and the address information search process in step S910 in FIGS. 11A and 11B are processes performed by the address information comparison / determination unit 203. The processes of step S902, step S905, step S909, part of step S910, and step S913 are processes performed by the communication path connection request transmission / response reception unit 212. The processing of step S903, step S904, step S907, step S908, step S911, and step S912 is processing performed by the communication path establishment determination unit 204.

  The processing of Step S1000 to Step S1003, Step S1006, Step S1008 in FIG. 19A, Step S1100 to Step S1004, Step S1108, and Step S1109 in FIG. Steps S1004, S1005, S1007, S1008 in FIG. 19A and steps S1105, S1106, and S1110 in FIG. 19A are processes performed by the communication path connection request transmission / response reception unit 212. The processing in step S1009 is processing performed by the communication path establishment determination unit 204. The processes in steps S1010 and S1107 are processes performed by the communication method switching unit 206.

  The function of each block in the above description is organized as follows.

  The address information notification request transmission / response reception unit 209 acquires global address information assigned to the user terminal by the user terminal using the P2P server 3.

  The static NAT setting request unit 210 causes the upper router to set an address translation rule, and acquires WAN address information of the upper router.

  The communication start request transmission / response reception unit 211 receives the global address information acquired from the P2P server 3, the WAN address information of the address conversion rule set in the upper router, and the local address information via the P2P server 3. Send to.

  The P2P communication processing unit 213 performs P2P communication using the notified address information.

  The address information comparison / determination unit 203 compares the notified global address information, WAN side address information, and local address information with respect to whether or not the global address information is equal between itself and the communication partner. Based on the comparison result, the communication path connection request transmission / response reception unit 212 connects or communicates using local address information and / or WAN side address information. Also, the address information comparison / determination unit 203 performs NAT setting inspection of the router immediately above itself, NAT setting inspection of the router immediately above the communication partner, presence / absence of the upper router two layers of the communication partner, At least one of the matching of the WAN side IP address of the upper router is performed to determine whether or not direct communication is possible.

  The communication path connection request transmission / response receiving unit 212 tries to connect or communicate in the order of the local address information of the communication partner, the WAN side address information, and the global address information. If the attempt is unsuccessful, the communication path connection request transmission / response reception unit 212 waits for a connection from the communication partner. About the exchanged global address information, WAN side address information, and local address information, the global address information is the same between itself and the communication partner, and based on the notified address information of the communication partner and its address information, The address information comparison / determination unit 203 determines whether or not direct communication is possible using the address information. If the address information comparison / determination unit 203 determines that communication is possible, the communication path connection request transmission / response reception unit 212 receives the local address information and the WAN. The side address information or either one is used for connection or communication.

  The communication start request transmission / response reception unit 211 notifies the communication partner of global address information, WAN side address information, and local address information. When the address information comparison / determination unit 203 determines that the global address information is not equal between itself and the communication partner, the communication path connection request transmission / response reception unit 212 uses the global address information to connect or communicate.

  The address information comparison / determination unit 203 checks the communication partner's global IP address in the order of local address information, WAN address information, and global address information. Based on the result, the communication path connection request transmission / response receiving unit 212 attempts connection or communication to address information corresponding to the global IP address, and when the attempt is unsuccessful, waits for connection from the communication partner.

  Also, the address information comparison / determination unit 203 has the global address information exchanged for the exchanged global address information, the WAN address information, and the local address information, and the address information of the notified communication partner is not equal to that of the communication partner. Based on the address information, it is determined whether or not direct communication is possible using the address information. If direct communication is possible, the communication path connection request transmission / response reception unit 212 uses the global address information to connect or communicate.

  Also, the address information comparison / determination unit 203 performs NAT setting inspection of the router immediately above itself, NAT setting inspection of the router immediately above the communication partner, presence / absence of the upper router two layers of the communication partner, At least one of the matching check of the WAN side IP address of the upper router is performed.

  The communication method switching unit 206 determines whether the address information comparison / determination unit 203 can directly communicate using the address information of the communication partner and the address information of the communication method switching unit 206 using the address information. If it is determined to be impossible, communication is performed by switching the communication method.

  Based on the exchanged address information, the NAT setting change request unit 217 deletes an unnecessary address translation rule set in the immediately above router. For example, the NAT setting change request unit 217 may delete the static NAT setting when it is determined that the P2P communication is impossible due to the static NAT setting.

  When the NAT setting change request unit 217 starts P2P communication, if the address conversion rule set in the upper router is a partner non-limiting type that does not limit the communication partner, the NAT setting change request unit 217 changes to a partner-limited address conversion rule that limits the communication partner. To do. Here, the partner non-restricted NAT refers to a NAT other than the Full-Cone NAT.

  In FIG. 20, an address information comparison / determination unit 203, a communication path establishment determination unit 204, a control unit 205, a communication method switching unit 206, an application processing unit 207, an identification information registration transmission unit 208, an address information notification request transmission / response reception unit 209. , Static NAT setting request unit 210, communication start request transmission / response reception unit 211, communication path connection request transmission / response reception unit 212, P2P communication processing unit 213, P2P server route method processing unit 214, STUN method processing unit 215 It can be configured by individual hardware. Generally, as shown in the first and second embodiments, these functional blocks can be realized by executing a program (P2P communication program) on a computer device. Accordingly, each functional block is realized on a CPU, a memory such as a RAM and a ROM, and an HDD on a known computer system. That is, each functional block may physically share hardware. Each functional block may be realized by an individual program that is completely independent, or may be realized by a partially shared program.

(Fourth embodiment)
In each of the above embodiments, the dynamic NAT setting is automatically performed by the router upon transmission from the user terminal.

  In the dynamic NAT setting, the address information is converted according to the NAT conversion table based on the address conversion rule regardless of the data transmission source, and the dynamic NAT setting that converts the address information only when there is a reply from the communication partner. There is a dynamic NAT configuration.

  In the former case, it is a partner-limited NAT setting in which the data transmission source is limited. When the dynamic NAT setting set at the time of transmission from the user terminal to the P2P server 3 is the partner-limited NAT setting, data does not reach the user terminal unless the transmission source is the P2P server 3. Therefore, the partner-limited dynamic NAT setting set at the time of transmission from the user terminal to the P2P server 3 cannot be used for communication between the user terminals. Therefore, in each of the above embodiments, the user terminal causes the router immediately above to perform static NAT setting. However, when the static NAT setting is performed before communication between user terminals as in step S503 in FIG. 5, a reply from the user terminal that is the communication partner cannot be specified. Therefore, the static NAT setting in each of the above embodiments must be a mode in which NAT conversion is performed regardless of the transmission source, that is, a partner-unlimited static NAT setting.

  The fourth embodiment proposes a user terminal that can switch a partner-unlimited static NAT setting to a partner-limited static NAT setting.

  As shown in FIGS. 14A and 14B, the user terminal knows the local IP address and port number of the communication partner at the stage of exchanging address information. Therefore, the user terminal switches the setting of the router so as to perform NAT conversion based on the static NAT setting only when the address information of the communication partner is the transmission source. That is, the user terminal switches the router setting to the partner-limited static NAT setting when the address information of the communication partner is known.

  For example, the user terminal additionally describes the address information of the communication partner in the AddPortMapping action message, transmits it to the router immediately above, and instructs to limit the address information conversion partner. The WAN side IP address and port number of the static NAT setting have already been notified to the communication partner. Therefore, when instructing to limit the address information conversion partner, the user terminal only needs to limit the destination address information of the reception destination without changing the WAN-side IP address and port number.

  Thus, after the P2P communication is started and the address information related to the communication partner is obtained, the user terminal changes the static NAT setting so as to limit the communication partner, so that a user terminal other than the user terminal that desires the communication It is possible to avoid receiving malicious communication. Therefore, security is improved.

  If the communication partner cannot be limited by the currently known AddPort Mapping action message, the user terminal may define and use a new Add Port Mapping action message to which an area in which address information of the communication partner can be described is added. .

  In step S604 of FIG. 10, since the user terminal already knows the address information of the other party, it is preferable to perform the partner-limited static NAT setting on the router from the beginning.

(Fifth embodiment)
As described above, the router performs partner-limited or partner-unlimited dynamic NAT setting during communication by the user terminal.

  In the above embodiment, the user terminal performs static NAT setting on the router in step S503 in FIG.

  However, in the fifth embodiment, in step S503 in FIG. 7, the user terminal does not perform static NAT setting for the router, but performs partner-unlimited dynamic NAT setting for the router. In step S503, the user terminal obtains the WAN-side IP address and port number in the partner-unlimited dynamic NAT setting from the router, stores them as upper router WAN-side address information, and stores the WAN-side address. Information is transmitted to the communication partner user terminal via the P2P server 3. Similarly, in step S604 of FIG. 10, the communication partner user terminal may similarly perform partner non-limiting dynamic NAT setting on the router.

  In order to realize the fifth embodiment, the user terminal needs to have a function of instructing the router in a mode in which the partner-unlimited NAT conversion is performed. Also, the router needs to have a function of setting a non-restricted NAT conversion mode in response to the above instruction. Further, the user terminal and the router need to have a function of communicating a telegram and a reply telegram for transmitting and receiving the WAN side IP address and port number as address information set in the router. Thereby, the router does not need to perform static NAT setting.

  For example, a communication device that is a user terminal includes a control unit 205 and a NAT setting change request unit 217. The control unit 205 inquires of the upper router whether the address translation rule of the dynamic NAT setting set in the upper router is the partner limited type or the partner non-limited type. When the partner-limited address translation rule is set in the upper router, the NAT setting change request unit 217 changes the already-configured dynamic NAT setting address translation rule to the partner non-limiter so as to change the address translation rule. To request. As the request message, a format obtained by modifying the message described in the static NAT setting can be used. The NAT setting change request unit 217 may be provided in parallel with the static NAT setting request unit 210. The control unit 205 performs management of the NAT setting status of the upper router and WAN side address information, operation management of the NAT setting change request unit, and operation instruction.

(Sixth embodiment)
In the fourth and fifth embodiments, the control for limiting the communication partner in the dynamic NAT setting and the static NAT setting in the process up to the address information exchange via the P2P server 3 has been described. The sixth embodiment is an embodiment in which, in the start of communication between user terminals, the transmission source partner of NAT conversion is limited.

  When transmitting from the user terminal on the transmission start side to the user terminal of the communication partner, dynamic NAT setting is automatically performed. The user terminal may set and use this dynamic NAT setting in a partner-limited type that performs NAT conversion only for a reply from a communication partner. For this purpose, after communication started by static NAT setting, the user terminal on the transmission start side obtains the WAN side IP address and port number of dynamic NAT setting of its own upper router, and uses this as the communication partner. Notify Thereafter, the communication partner user terminal may use the WAN IP address and port number of the new dynamic NAT setting as the reply destination. The upper router of the user terminal on the transmission start side does not need the previously set static NAT setting. Therefore, the upper router may delete the unnecessary NAT setting as in an eighth embodiment described later.

  In order to make the dynamic NAT setting limited to the other party, the communication device that is a user terminal may include a control unit 205 and a NAT setting change request unit 217. The control unit 205 inquires to the upper router and inspects whether the address conversion rule of the dynamic NAT setting set in the upper router is the partner limited type or the partner non-limited type. When the partner is not limited, the NAT setting change request unit 217 requests the upper router to change the address translation rule to the partner limited type. The request message can use the message in the format described in the static NAT setting. The NAT setting change request unit 217 may be provided in parallel with the static NAT setting request unit 210. The control unit 205 performs management of the NAT setting status of the upper router and WAN side address information, operation management of the NAT setting change request unit, and operation instruction.

(Seventh embodiment)
The sixth embodiment is an example in which the upper router of the user terminal on the transmission start side is switched to the partner-limited dynamic NAT setting after the partner-unlimited static NAT setting. When the static NAT setting is continuously used, the user terminal may be switched to the partner-limited static NAT setting after the partner-unlimited static NAT setting. The communication partner user terminal may also switch to the partner-limited dynamic NAT setting after the partner-unlimited static NAT setting. Alternatively, the communication partner user terminal may be switched to the partner-limited static NAT setting after the partner-unlimited static NAT setting.

  In order to realize this function, the user terminal may include a control unit 205 and a NAT setting change request unit 217. The control unit 205 inquires of the upper router and inspects whether the address translation rule set in the upper router is the partner limited type or the partner non-limiting type. The NAT setting change request unit 217 requests the upper router to change the desired NAT setting to a desired address translation rule. The request message can use the message in the format described in the static NAT setting. The NAT setting change request unit 217 may be provided in parallel with the static NAT setting request unit 210. The control unit 205 performs management of the NAT setting status of the upper router and WAN side address information, operation management of the NAT setting change request unit, and operation instruction.

(Eighth embodiment)
In the eighth embodiment, as a modification of each of the above embodiments, a user terminal capable of deleting a NAT setting when communication fails or when it is determined that a preset NAT setting is not necessary will be described. . Thereby, it is possible to prevent the NAT conversion table from overflowing and improve security.

  For example, when it is determined that the P2P connection from the user terminal 1a to the user terminal 1e is possible as in the example illustrated in FIGS. 17A and 17B, the static NAT setting in the router 2A set by the user terminal 1a is unnecessary. This is because access to the router 2A is access from the LAN side to the WAN side, and a NAT conversion table is set by dynamic NAT, and this dynamic NAT is used thereafter in P2P communication. As described above, when it is determined that the NAT setting set by itself is no longer necessary, the NAT setting change request unit 217 of each user terminal may delete the NAT setting.

  When the UPnP / IGD protocol is used, the user terminal can delete the NAT setting of the upper router by transmitting a DelPortMapping action message to the upper router. A plurality of dynamic NATs and static NATs may be set in the upper router. The user terminal requests the deletion of the NAT setting by designating the port number when the user terminal has performed the static NAT setting.

  In the fourth to seventh embodiments, the security is improved by switching from the partner-unlimited NAT setting to the partner-limited NAT setting. The user terminal may delete the NAT setting that is no longer necessary at the time of this switching.

  When both dynamic NAT setting and static NAT setting are performed, the user terminal may delete the NAT setting that can be determined to be unnecessary.

  Normally, in the case of TCP communication, the dynamic NAT setting is canceled when the session is disconnected. That is, the corresponding column in the NAT conversion table is generally deleted. However, the present invention is not limited to this. In the case of UDP communication, if the packet does not flow for a certain time (usually several tens of seconds to several minutes), the dynamic NAT setting is canceled. As described above, the dynamic NAT setting is generally automatically deleted when communication is completed without performing an explicit deletion procedure. However, the present invention is not limited to this.

  The present invention notifies the communication partner of the address information of the upper router obtained by UPnP or the like, the global address information obtained by using the server, and the local address information set in the user terminal itself. It is characterized in that appropriate connection destination address information is determined based on the information and the information of the communication partner, and P2P communication is performed. In addition, there is a feature in that a static NAT setting necessary for P2P communication is determined. Furthermore, when it is determined that P2P communication by static NAT setting is not possible, the P2P communication method is switched and P2P communication is enabled using relay by STUN or P2P server.

  In FIG. 7, the order of step S502 for acquiring the WAN side address information of the upper router from the user terminal and step S503 for setting the address information conversion rule of the upper router from the user terminal may be reversed. Similarly, the order of step S603 and step S604 may be reversed. Further, in each of the above embodiments, the user terminal exchanges address information after performing NAT setting of the upper router. However, the user terminal obtains only the WAN side address information of the upper router, and at the stage of obtaining, after exchanging the address information without performing the NAT setting, the user terminal determines the router that needs the NAT setting, and sets the NAT setting. May be performed.

  The network to which the present invention can be applied must be a network that can communicate with each other between the P2P server 3, the router 2C, and the router 2D directly or indirectly. The present invention provides communication between a user terminal under the router 2C and a user terminal under the router 2D, communication between user terminals on the same subnetwork, and between the user terminal 1a and the user terminal 1b. Communication between relations not via a router is possible. Even if the address information of the other party is not known, the user terminal of the present invention can substantially perform P2P communication if there is a method for obtaining the other party address information by a known method. The user terminal can communicate up to a router on the way, and the router once receives data from the user terminal, but the user terminal of the present invention also has a problem that the data cannot exceed the router. Can perform P2P communication. Although two user terminals are physically connected or coupled, even if logically P2P communication is not possible, P2P communication is possible using the present invention.

  P2P communication is desired when there is no router above the at least one user terminal among the two user terminals subject to P2P communication, that is, when at least one user terminal is directly connected to the Internet network The user terminal obtains global address information of the user terminal directly connected to the Internet network from the P2P server 3. A user terminal desiring P2P communication transmits a communication path connection request to a communication partner with the obtained global address information as a destination. As a result, dynamic NAT setting is performed, a return communication path is set, and P2P communication is enabled. The present invention is applicable to P2P communication in the network configuration as described above. When one user terminal is under the router, the user terminal under the router performs static NAT setting for the router. Therefore, the communication path connection request from either one of the user terminals reaches the communication partner. Therefore, P2P communication is possible.

  In the network shown in FIG. 1, it is assumed that there is a user terminal 1f immediately below the router 2C. At this time, in order for the user terminal 1f to perform P2P communication with the user terminal 1c, each user terminal must recognize that the user terminal 1f and the user terminal 1c exist immediately below the router 2C. This is possible with the user terminal of the present invention.

  In each of the above embodiments, a network having a two-layered router, such as the router 2C and the router 2A, is assumed. However, the present invention can also be applied to a network having a router having a structure of three or more layers. In particular, in a network having three or more layers of routers, P2P communication can be expected to be performed between user terminals existing within the range of a two-layer structure. Of course, P2P communication can be performed even between user terminals existing in the range of three layers or more if the conditions are met.

  As shown in FIGS. 14A and 14B, in the address information exchanged between the user terminal 1a and the user terminal 1d, the port number of each local address information is the port number that is actually scheduled to be used for P2P communication. It only has to be set.

  In a network environment using DHCP (Dynamic Host Configuration Protocol) as in a home network, address information may change. However, as long as the identification information is known, the user terminal can register the identification information in the P2P server 3 even if the address information changes. Therefore, the user terminal can perform P2P communication.

  The user terminal may notify only the WAN address information, only the global address information acquired from the server, or both of the address information. The case where only the WAN address information only needs to be notified and the case where only the global address information needs to be notified are cases where the global IP address and the WAN side IP address match. In other words, the router directly above is connected directly to the Internet. The case where only notification of global address information is sufficient is a case where the upper router is a router not supporting UPnP. The case where the notification of the local address information is unnecessary is a case where the user terminal is directly connected to the Internet without going through a router. In this case, the user terminals need only exchange global address information.

  Assignment and management of identification information may be performed in the same manner as conventional DNS and dynamic DNS. That is, in dynamic DNS, first, unique identification information (domain name) is assigned to a user terminal. The user terminal declares identification information to be assigned to the server. The server determines whether or not the reported identification information overlaps with the identification information assigned to another user terminal. If there is no overlap, the server assigns the reported identification information to the user terminal. The server registers the address information corresponding to the identification information every time it is changed.

  In each of the above embodiments, the address information or the network configuration is investigated at the start of P2P communication. However, it may be performed in advance when the terminal is activated. Furthermore, it is also possible to register in the P2P server its own network configuration information that has been found in advance when the terminal is activated. When the user terminal wants to perform P2P communication, it can obtain information on the network configuration of itself and the other party from the P2P server. That is, each terminal registers its own address information (network configuration information) in the P2P server, and each terminal acquires the network configuration information of the communication partner from the P2P server.

  Further, the user terminal may periodically check the network configuration. When the network configuration information changes, the user terminal may update the registered content in the P2P server.

  In the above embodiment, the user terminal performs static NAT setting, acquires WAN address information, and transmits a communication start request message to the communication partner. However, the user terminal may exchange address information with the communication terminal of the communication partner without performing static NAT setting. FIG. 21A and FIG. 21B are sequence diagrams showing the operation of the user terminal when address information is exchanged without performing static NAT setting.

  First, the user terminal 1a establishes a communication path with the P2P server 3 (P20). Next, the user terminal 1d establishes a communication path with the P2P server 3 (P21). Next, the user terminal 1a acquires global address information from the P2P server 3 (P23). Next, the user terminal 1a acquires the WAN-side IP address as the WAN-side address information assigned to the router 2A directly above (P24). For example, the user terminal 1a obtains the WAN-side IP address of the router 2A immediately above it using UPnP's GetExternalAddress action.

  Next, the user terminal 1a transmits an address information exchange request message to the user terminal 1d via the P2P server 3 (P25). The address information exchange request message includes only the global IP address, WAN side IP address, and local IP address assigned to the user terminal 1a. Since the global IP address is information related to the address of the user terminal on the Internet, it can be said to be global address information. The WAN-side IP address is information on the WAN-side address assigned to the router directly above, and thus can be said to be WAN-side address information. Since the local IP address is information relating to an address assigned to the own device on the local network, it can be said to be local address information.

  The user terminal 1d that has received the address information exchange request message acquires global address information from the P2P server 3 (P26). Next, the user terminal 1d tries to acquire the WAN side IP address as the WAN side address information assigned to the router 2B immediately above (P27). Here, it is assumed that the router 2B does not support UPnP. Therefore, the user terminal 1d cannot acquire WAN side address information.

  Next, the user terminal 1d transmits an address information exchange response message to the user terminal 1a via the P2P server 3 (P28). Here, the address information exchange response message includes only the global IP address, WAN side IP address, and local IP address assigned to the user terminal 1d. However, as shown in FIG. 21A, if the router immediately above does not support UPnP, the WAN side IP address is not included in the address information exchange response message.

  The user terminal 1a that has received the address information exchange response message determines whether or not to perform static NAT setting (P29). The user terminal 1d that has transmitted the address information exchange response message determines whether or not to perform static NAT setting (P30).

  Here, it is assumed that the user terminal 1a determines to perform static NAT setting. The user terminal 1a causes the router 2A immediately above to set a static NAPT by UPnP (P31). Next, the user terminal 1a transmits a communication start request message to the user terminal 1d via the P2P server 3 (P32). The communication start request message includes global address information including an IP address and a port number, WAN side address information, and local address information.

  The user terminal 1d that has received the communication start request message transmits a communication start response message to the user terminal 1a via the P2P server 3 (P33). The communication start response message includes global address information including an IP address and a port number, WAN side address information, and local address information.

  Since the address information has been exchanged in this way, the user terminal 1a and the user terminal 1d start P2P communication in the same manner as the processing in the first or second embodiment. For example, the user terminal 1a and the user terminal 1d start P2P communication in the same manner as the processing shown after P9 in FIG. 18B.

  FIG. 22 is a flowchart showing the operation of the user terminal when determining whether or not to perform static NAT setting. Hereinafter, the operation of the user terminal when determining whether or not to perform static NAT setting will be described with reference to FIG. The operation of FIG. 22 is performed at P29 and P32 shown in FIG. 21B, for example.

  First, the user terminal determines whether or not P2P communication is possible based on the address information acquired from the communication partner user terminal, and if not, switches the connection method (step S1200). Only when the global IP address is different, the user terminal performs the determination in step S1200.

  Next, the user terminal determines whether or not the global IP address assigned to the own device matches the global IP address assigned to the communication partner user terminal (step S1201). If they match, the communication between the own device and the communication partner is communication under the same router, and therefore the user terminal performs static NAT setting by UPnP for the router immediately above (S1202). Note that the user terminal may perform static NAT setting other than UPnP.

  On the other hand, if they do not match, communication between the own device and the communication partner is communication via the Internet. In this case, the user terminal determines whether or not the WAN-side IP address assigned to the own device matches the global IP address (step S1203).

  If they match in step S1203, the user terminal proceeds to the operation in step S1202. On the other hand, if they do not match, the static NAT cannot be set in the uppermost router, and therefore the user terminal determines not to perform the static NAT setting (step S1204). The user terminal that has determined that static NAT setting is not performed starts P2P communication via the P2P server 3 or starts P2P communication using the STUN communication method.

  In this way, the user terminal determines whether or not static NAT should be set based on the global address information of the own device and the communication partner and the WAN address information of the own device. Such a determination can also be realized by providing the user terminal with a NAT setting determination unit (not shown). When it is not determined that the static NAT should be set, the user terminal switches the communication method. As a result, unnecessary static NAT setting is not performed, so that improvement in security and speeding up of processing can be expected.

  The program of the present invention may be provided by being stored in a computer-readable recording medium, or may be provided to a computer device via a network.

  The functional blocks necessary for realizing the terminal of the present invention may be realized as an LSI that is an integrated circuit. These functional blocks may be made into one chip, or may be made into one chip so as to include a part or all of them. Although referred to here as LSI, depending on the degree of integration, it may be referred to as IC, system LSI, super LSI, or ultra LSI. Further, the method of circuit integration is not limited to LSI, and circuit integration may be performed with a dedicated circuit or a general-purpose processor. Also, an FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used. Further, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to integrate function blocks using this technology. There is a possibility of adaptation of biotechnology.

  Although the present invention has been described in detail above, the above description is merely illustrative of the present invention in all respects and is not intended to limit the scope thereof. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention.

  The communication apparatus, method, and program according to the present invention can realize P2P communication via a home network or the Internet, and are useful in the communication field and the like.

The figure which shows an example of the structure of the network in which the P2P communication control in the 1st Embodiment of this invention is performed The figure which shows the other example of the structure of the network in which the P2P communication control in the 1st Embodiment of this invention is performed. The block diagram which shows the hardware constitutions of user terminal 1a-1e which is a communication apparatus The figure which shows an example of the IP address allocated to the user terminals 1a-1e and the P2P server 3 The figure which shows an example of the WAN side IP address and LAN side IP address which are allocated to the router The block diagram which shows the functional structure of the user terminal which is a communication apparatus when a P2P communication program is performed The flowchart which shows operation | movement of the user terminal 1a and the P2P server 3 at the time of performing identification information registration processing The figure which shows an example of an identification information management table The flowchart which shows operation | movement of the user terminal of the transmission side which performs transmission side information exchange processing, and operation | movement of the P2P server 3 The figure which shows an example of a format of an address information notification request message The figure which shows an example of a format of an address information notification response message The figure which shows an example of a format of a communication start request message The figure which shows an example of a format of a communication start response message A flowchart showing the operation of the user terminal on the called side that executes the information exchange processing on the called side and the operation of the P2P server 3 A flowchart showing an operation when a user terminal having exchanged address information actually performs P2P communication. A flowchart showing an operation when a user terminal having exchanged address information actually performs P2P communication. The figure which shows an example of the communication start request message when the communication path for P2P communication cannot be ensured The figure which shows an example of the communication start response message when the communication path for P2P communication cannot be ensured The figure which shows the other example of a communication start request message when the communication path for P2P communication cannot be ensured. The figure which shows the other example of a communication start response message when the communication channel for P2P communication cannot be ensured. The figure which shows an example of the content of the communication start request message transmitted from the user terminal 1a to the user terminal 1d The figure which shows an example of the content of the communication start response message transmitted to the user terminal 1a from the user terminal 1d The figure which shows an example of the content of the communication start request message transmitted from the user terminal 1a to the user terminal 1b The figure which shows an example of the content of the communication start response message transmitted to the user terminal 1a from the user terminal 1b The figure which shows an example of the content of the communication start request message transmitted from the user terminal 1a to the user terminal 1c The figure which shows an example of the content of the communication start response message transmitted to the user terminal 1a from the user terminal 1c The figure which shows an example of the content of the communication start request message transmitted to the user terminal 1e from the user terminal 1a The figure which shows an example of the content of the communication start response message transmitted to the user terminal 1a from the user terminal 1e The figure which shows the specific communication sequence for performing P2P communication between the user terminal 1a and the user terminal 1d. The figure which shows the specific communication sequence for performing P2P communication between the user terminal 1a and the user terminal 1d. The flowchart which shows operation | movement of the user terminal in 2nd Embodiment. The flowchart which shows operation | movement of the user terminal in 2nd Embodiment. The block diagram which shows the detailed functional structure of the communication apparatus which is a user terminal which can perform the P2P communication system of this invention Sequence diagram showing operation of user terminal when address information is exchanged without setting static NAT Sequence diagram showing operation of user terminal when address information is exchanged without setting static NAT The flowchart which shows operation | movement of a user terminal when determining whether static NAT setting is performed.

Explanation of symbols

1, 2 Home networks 1a to 1b User terminals 2A to 2D Router 21 NAT function unit 3 P2P server 4 Internet 10 Central processing unit 11 Main storage device 12 Auxiliary storage device 13 Communication device 14 Input / output device 101 Global address information acquisition unit 102 NAT Setting request unit 103 WAN address information acquisition unit 104 Local address information acquisition unit 105 Address information notification unit 106 Address information acquisition unit 107 Used address information determination unit 108 P2P communication processing unit

Claims (17)

A communication device connectable to a network including the Internet,
A global address information acquisition unit that communicates with a server on the network and acquires, as first global address information, information related to an address on the Internet assigned to the device;
WAN-side address information acquisition means for acquiring, as first WAN-side address information, information related to the address on the WAN side that is assigned to a router that exists immediately above the own device;
Local address information acquisition means for acquiring, as first local address information, information relating to an address on the local network assigned to the device;
Notification of the first global address information, the first WAN side address information, and the first local address information to a communication apparatus that desires P2P communication via a server on the network. Address information notification means to perform,
Via the server on the network, second global address information that is information related to the address on the Internet that is assigned to the communication device of the communication partner, assigned to the router that exists immediately above the communication device of the communication partner Second WAN address information that is information related to the address on the WAN side that has been assigned, and second local address information that is information related to the address on the local network assigned to the communication device of the communication partner Address information acquisition means for
A communication apparatus that determines a method capable of P2P communication based on the first and second global address information, WAN address information, and local address information. Furthermore, the router has a NAT setting request means for setting an address translation rule for the router immediately above its own device,
2. The communication apparatus according to claim 1, wherein the WAN address information acquisition unit acquires the first WAN address information assigned to the own apparatus based on the address conversion rule set in the router. 3. . Furthermore, the NAT setting request means comprises NAT setting judgment means for judging whether or not to set the address translation rule,
2. If the NAT setting determining means does not determine that the address conversion rule should be set, a method capable of P2P communication is determined without causing the NAT setting request means to set the address conversion rule. The communication apparatus as described in. Furthermore, the address information acquisition means uses the address information of any one of the second global address information, the second WAN side address information, and the second local address information. Use address information judging means for judging whether or not to start P2P communication with the communication device of the communication partner;
P2P communication for starting P2P communication with the communication apparatus of the communication partner using the address information when it is determined by the use address information determination means to start P2P communication using any one of the address information The communication apparatus according to claim 1, comprising processing means.   The used address information determining means transmits a P2P connection request with one of the second global address information, the second WAN address information, and the second local address information as a destination. The communication apparatus according to claim 4, wherein when a response is returned from the communication apparatus of the communication partner, it is determined to start P2P communication using the address information used as the destination. When the P2P connection request from the communication partner communication device is received, the use address information determination unit determines to start P2P communication using the source address information of the P2P connection request,
When the P2P communication processing means determines that the use address information determination means starts the P2P communication using the transmission source address information, the P2P communication processing means uses the transmission source address information to communicate with the communication partner communication apparatus. The communication device according to claim 5, wherein the communication device starts P2P communication.   If it is not determined by the use address information determination means to start P2P communication using any one of the address information and it is not determined to start P2P communication using the source address information, the P2P communication The communication apparatus according to claim 6, wherein the communication processing unit determines to start P2P communication using a P2P communication method or a STUN communication method via the server. The used address information judging means judges whether or not a first global IP address included in the first global address information is equal to a second global IP address included in the second global address information. ,
When the first global IP address is not equal to the second global IP address, a P2P connection request is transmitted with address information corresponding to the second global IP address as a destination, and the communication partner communication apparatus When a response is returned, it is determined to start P2P communication using the address information used as the destination,
When the first global IP address is the same as the second global IP address, a P2P connection is made with any one of the second WAN address information and the second local address information as a destination The communication apparatus according to claim 5, wherein when a request is transmitted and a response is returned from the communication apparatus of the communication partner, it is determined to start P2P communication using the address information used as the destination. The use address information judging means includes:
Determining whether the first and second global address information and the first and second WAN side address information belong to a predetermined type;
Depending on the type to which the first and second global address information and the first and second WAN address information belong, the address information to be used as the destination is the second global address information, the second WAN. Predetermined from the side address information and the second local address information,
5. The communication according to claim 4, wherein it is determined to start P2P communication using address information corresponding to a type to which the first and second global address information and the first and second WAN side address information belong. apparatus. The predetermined type is:
A first type indicating that it is connected to the communication device of the communication partner via the Internet;
A second type indicating that the communication device of the communication partner is not connected via the Internet;
A third type indicating that a router existing immediately above the communication apparatus of the communication partner is set to static NAT;
A fourth type indicating that a static NAT setting is not set for a router immediately above the communication apparatus of the communication partner;
A fifth type indicating that there is only one router between the communication device of the communication partner and the Internet;
A sixth type indicating that there are at least two routers between the communication device of the communication partner and the Internet;
A seventh type indicating that the first WAN-side IP address included in the first WAN-side address information matches the second WAN-side IP address included in the second WAN-side address information;
An eighth type indicating that the first WAN-side IP address included in the first WAN-side address information does not match the second WAN-side IP address included in the second WAN-side address information;
A ninth type indicating that the router immediately above the local device is set to static NAT;
A tenth type indicating that the router directly above the local device is not set to static NAT;
An eleventh type indicating that only one router exists between the own device and the Internet;
A twelfth type indicating that there are at least two routers between the device and the Internet;
The used address information judging means includes second WAN address information, second local address according to a type to which the first and second global address information and the first and second WAN address information belong. Whether to start P2P communication using the address information of any one of the information or the source address information in the communication path connection request from the communication partner of the communication partner, or to switch the P2P communication method The communication device according to claim 9, wherein the communication device is determined.   The P2P communication processing means determines to start P2P communication using the P2P communication method or STUN communication method via the server when a communication path for P2P communication with the communication partner communication device is not established. The communication device according to claim 10. The used address information judging means is based on the first and second global address information, the first and second WAN address information, and the first and second local address information. Using the address information to determine whether or not P2P communication with the communication device of the communication partner is possible;
The P2P communication processing means uses the P2P communication system or STUN communication system via the server when the use address information determination means determines that P2P communication with the communication partner communication apparatus is impossible. The communication apparatus according to claim 4, wherein the communication apparatus determines to start P2P communication.   The communication apparatus according to claim 2, further comprising a NAT setting change request means for deleting an unnecessary address translation rule set in the router.   The communication apparatus according to claim 2, further comprising a NAT setting change request unit that changes the address conversion rule set in the router to a partner-limited type that limits a communication partner after the start of P2P communication. A communication device connectable to a network including the Internet is a method for P2P communication with another communication device,
Communicating with a server on the network to obtain information on an address on the Internet assigned to the device as first global address information;
Obtaining information on the address on the WAN side assigned to the router immediately above the own device as the first WAN side address information;
Obtaining information on an address on the local network assigned to the device as first local address information;
Notifying the other communication device of the first global address information, the first WAN address information, and the first local address information via a server on the network;
Via the server on the network, the second global address information that is information related to the address on the Internet assigned to the other communication device, assigned to the router that exists immediately above the other communication device. Obtaining second WAN side address information that is information related to an address on the WAN side that is present, and second local address information that is information related to an address on a local network assigned to the other communication device When,
Determining a scheme capable of P2P communication based on the first and second global address information, WAN address information, and local address information. A program for operating a computer device that can be connected to a network including the Internet to perform P2P communication with another computer device,
In the computer device,
Communicating with a server on the network to obtain information on an address on the Internet assigned to the device as first global address information;
Obtaining information on the address on the WAN side assigned to the router immediately above the own device as first WAN side address information;
Obtaining information on an address on the local network assigned to the device as first local address information;
Notifying the other computer apparatus of the first global address information, the first WAN address information, and the first local address information via a server on the network;
Second global address information, which is information related to addresses on the Internet, assigned to the other computer device via a server on the network, assigned to a router immediately above the other computer device. Obtaining second WAN address information which is information related to an address on the WAN side, and second local address information which is information related to an address on a local network assigned to the other computer device When,
A program for executing a step of determining a method capable of P2P communication based on the first and second global address information, WAN address information, and local address information. A communication device connectable to a network,
Global address information acquisition means that communicates with a server on the network and acquires, as first global address information, information related to an address assigned to the own device on a subnetwork to which the server belongs;
WAN-side address information acquisition means for acquiring, as first WAN-side address information, information related to the address on the WAN side that is assigned to a router that exists immediately above the own device;
Local address information acquisition means for acquiring, as first local address information, information relating to an address on the local network assigned to the device;
Notification of the first global address information, the first WAN side address information, and the first local address information to a communication apparatus that desires P2P communication via a server on the network. Address information notification means to perform,
Via a server on the network, second global address information, which is information relating to an address on the subnetwork assigned to the communication device of the communication partner, to a router immediately above the communication device of the communication partner Second WAN address information that is information related to the address on the assigned WAN side, and second local address information that is information related to the address on the local network assigned to the communication device of the communication partner. Address information acquisition means for acquiring,
A communication apparatus that determines a method capable of P2P communication based on the first and second global address information, WAN address information, and local address information.

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