JP2012054648A - Node device, information communication system, information communication method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a peer-to-peer (P2P) system operate even in a network environment where the IPv4 and IPv6 are employed together.SOLUTION: In an embodiment, there are two types of overlay networks. They are a first overlay network PW and a second overlay network PL, as shown in Fig. 2. The first overlay network PW is comprised of any of node devices capable of communicating according to the IPv4. The second overlay network PL is comprised of any of node devices capable of communicating according to the IPv6.

Description

  The present invention relates to a technical field of a peer-to-peer (P2P) communication system including a plurality of node devices that can communicate with each other via a network.

  In recent years, a peer-to-peer communication system as disclosed in Patent Document 1 has attracted attention. The peer-to-peer communication system is attracting attention as a new form that replaces the server client system, which is the mainstream form of current content distribution. In this peer-to-peer communication system, content requests to the server device at the center are not concentrated. Therefore, content can be acquired in a short time compared to the server client method. Specifically, Patent Document 1 discloses a technique in which a plurality of DHT (Distributed Hash Table) routing tables are generated for each group in units of software.

JP 2008-217135 A

  In recent years, with the depletion of IPv4 (Internet Protocol Version 4) address resources, the transition to IPv6 (Internet Protocol Version 6) is progressing. In the process of transitioning from IPv4 to IPv6, both IPv4 and IPv6 protocols may coexist in the network. When a P2P (Peer to Peer) type system operates in a network environment in which IPv4 and IPv6 coexist, different protocols are assigned to node devices connected to the P2P system. For example, IPv4 is assigned to a certain first node device, and IPv6 is assigned to a second node device different from the first node device. In this case, when the first node device and the second node device perform data communication by P2P, they cannot communicate because the protocol is different, and the P2P system cannot be operated.

  The present invention has been made in view of the above points. An object of the present invention is to provide a node device, an information communication system, an information communication method, a program, and the like that can operate a P2P system even in a network environment in which IPv4 and IPv6 coexist.

  According to the first aspect of the present invention, there is provided an information communication system that transmits and receives data through an overlay network composed of a plurality of node devices, and the node device includes IPv4 that is a protocol with which the node device can communicate. A protocol acquisition unit that acquires at least one of IPv6, a determination unit that determines whether the protocol acquired by the protocol acquisition unit is IPv4 or IPv6, and the protocol acquisition by the determination unit When it is determined that the protocol acquired by the unit is IPv4, the first overlay network is configured by at least a part of node devices that can communicate with IPv4, and participates in the first overlay network. The location of the node device on the network If the protocol acquired by the protocol acquisition unit is determined to be IPv6 by the first table acquisition unit that acquires the first routing table in which the location information is registered and the determination unit, communication is possible using IPv6. A second overlay network configured by at least a part of the node devices, and acquiring a second routing table in which the location information of the node devices participating in the second overlay network is registered. A message for controlling the information communication system is transmitted to the acquisition unit and the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the protocol acquisition unit. A first transmitter Is an information communication system characterized and.

  According to a second aspect of the present invention, the information communication system is capable of communicating by IPv4, and receives a participation message transmitted from the node device when participating in the information communication system. A second node device that can communicate with the device by IPv6 and receives a participation message transmitted from the node device when participating in the information communication system, the first transmission of the node device A second transmission unit configured to transmit the participation message to the first node device or the second node device capable of communicating with the protocol acquired by the protocol acquisition unit, and transmitted by the second transmission unit On the basis of the received participation message, the first table acquisition unit or the first table acquisition unit At least a portion of the routing table which the second node device stores, and acquires from the first node device or the second node device.

  According to a third aspect of the present invention, there is provided a node device of an information communication system that transmits and receives data through an overlay network composed of a plurality of node devices, and IPv4 and IPv6 that are protocols that the node device can communicate with. A protocol acquisition unit that acquires at least one of the following: a determination unit that determines whether the protocol acquired by the protocol acquisition unit is IPv4 or IPv6; and the determination unit by the protocol acquisition unit When it is determined that the acquired protocol is IPv4, the first overlay network is configured by at least a part of node devices that can communicate with IPv4, and the node device participates in the first overlay network. The location of the network on the network A first table acquisition unit that acquires a first routing table in which information is registered, and a node that can communicate with IPv6 when the determination unit determines that the protocol acquired by the protocol acquisition unit is IPv6 A second table acquisition unit, which is a second overlay network configured by at least a part of node devices of the device, and acquires a second routing table in which the location information of the node devices participating in the second overlay network is registered. And a message for controlling the information communication system to the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the protocol acquisition unit. A transmission unit, A node device according to symptoms.

  According to the invention described in claim 4, the plurality of node devices include a storage unit that stores data acquired from any of the plurality of node devices, and the node device stores data in the storage unit. The first routing table or the second routing table corresponding to the protocol acquired by the protocol acquisition unit, the notification message including the location information of the node device storing data. The first transmission unit transmits to the node device registered in at least one of the above.

  According to the fifth aspect of the present invention, the first transmission unit stores location information indicating a location on the network of one or more content holding node devices that hold desired content from the plurality of node devices. When the search message to be searched is further transmitted, the determination unit determines that communication is possible with both IPv4 and IPv6, and the first transmission unit transmits the search message, the first transmission unit Transmits the search message in preference to the location information registered in the second routing table over the first routing table.

  According to a sixth aspect of the present invention, the protocol acquisition unit acquires both IPv4 and IPv6, and the node device includes a reception unit that receives a message for controlling the information communication system, the reception unit When the node device that has received the control message by the communication unit can communicate with both IPv4 and IPv6, the first transmission unit converts the message received by the reception unit into the node that is the transmission source of the received message The apparatus transmits to a protocol different from a protocol with which the apparatus can communicate.

  According to the invention described in claim 7, the receiving unit searches for location information indicating a location on the network of one or more content holding node devices that hold desired content from the plurality of node devices. When the node device that has received the search message and has received the control message by the reception unit can communicate with both IPv4 and IPv6, the first transmission unit receives the search message received by the reception unit. The node device that is the transmission source of the received message transmits to a protocol that is different from a protocol that can be communicated, and the node device acquires content corresponding to the search message via the different protocol; The content acquired by the acquisition unit is stored in the source node of the message received by the reception unit. Characterized in that it comprises a relay unit that relays the de device.

  According to an eighth aspect of the present invention, there is provided an information communication method for an information communication system for transmitting and receiving data through an overlay network composed of a plurality of node devices, based on a protocol acquired by the node device. A determination step in which the node device determines whether a protocol that can be communicated by the node device is IPv4 or IPv6, and the determination step determines that the protocol acquired by the node device is IPv4. In this case, there is a first overlay network configured by at least a part of node devices that can communicate with IPv4, and location information indicating the location of the node devices participating in the first overlay network on the network is provided. Before the registered first routing table When the first table acquisition step acquired by the node device and the determination step determine that the protocol acquired by the node device is IPv6, at least some of the node devices that can communicate with IPv6 A second table acquiring step in which the node device acquires a second routing table in which the location information of the node devices participating in the second overlay network is registered, and the node A first transmission step of transmitting a message for controlling the information communication system to the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the device; Including information communication methods .

According to the invention of claim 9, the computer of the node device of the information communication system for transmitting and receiving data through an overlay network composed of a plurality of node devices,
Based on the protocol acquired by the node device, a determination step for determining whether a protocol communicable by the node device is IPv4 or IPv6, and the node device acquired by the determination step When it is determined that the protocol is IPv4, the network is a first overlay network composed of at least some of the node devices communicable with IPv4, and the network of the node devices participating in the first overlay network When it is determined that the protocol acquired by the node device is IPv6 by the first table acquisition step of acquiring the first routing table in which the location information indicating the location is registered, and the determination step, Node devices that can communicate with IPv6 A second table acquisition step of acquiring a second routing table in which the location information of the node devices participating in the second overlay network is registered, which is a second overlay network composed of at least some of the node devices; A first transmission step of transmitting a message for controlling the information communication system to the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the node device; And a program for executing the above.

  According to the first aspect of the present invention, when the determination unit determines that the protocol acquired by the protocol acquisition unit is IPv4, the first table acquisition unit is at least one of the node devices that can communicate with IPv4. A first routing table in which location information indicating the location on the network of node devices participating in the first overlay network is registered. The second table acquisition unit is a second table configured by at least a part of node devices communicable with IPv6 when the determination unit determines that the protocol acquired by the protocol acquisition unit is IPv6. A second routing table which is an overlay network and where location information of node devices participating in the second overlay network is registered is acquired. The first transmission unit transmits a message for controlling the information communication system to the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the protocol acquisition unit. As a result, even in a network environment in which IPv4 and IPv6 coexist, the P2P system can be operated using the first routing table and the second routing table.

  According to the second aspect of the present invention, the information communication system is capable of communication by IPv4, and receives a participation message transmitted from the node device when participating in the information communication system. And a second node device that is communicable with IPv6 and receives a participation message transmitted from the node device when participating in the information communication system. Based on the participation message transmitted by the second transmission unit, the first table acquisition unit or the second table acquisition unit stores at least a part of the routing table stored in the first node device or the second node device, Obtained from the first node device or the second node device. As a result, the IPv4 first routing table can be obtained from the first node device, and the IPv6 second routing table can be obtained from the second node device.

  According to the third aspect of the present invention, when the determination unit determines that the protocol acquired by the protocol acquisition unit is IPv4, the first table acquisition unit is at least one of the node devices that can communicate with IPv4. A first routing table in which location information indicating the location on the network of node devices participating in the first overlay network is registered. The second table acquisition unit is a second table configured by at least a part of node devices communicable with IPv6 when the determination unit determines that the protocol acquired by the protocol acquisition unit is IPv6. A second routing table which is an overlay network and where location information of node devices participating in the second overlay network is registered is acquired. The first transmission unit transmits a message for controlling the information communication system to the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the protocol acquisition unit. As a result, even in a network environment in which IPv4 and IPv6 coexist, the P2P system can be operated using the first routing table and the second routing table.

  According to the fourth aspect of the present invention, a notification message for notifying a plurality of node devices that the node device has stored data in the storage unit, the notification message including the location information of the node device storing the data. The first transmission unit transmits to the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the protocol acquisition unit. As a result, data can be acquired from the overlay network corresponding to the protocol with which the node device can communicate.

  Since IPv4 has a shortage of addresses, both global and private addresses are used. When a private address is used for communication, processing such as NAT traversal is necessary. On the other hand, since IPv6 has a large number of addresses, it is unlikely that both a global address and a private address are used. According to the invention of claim 5, when the determination unit determines that communication is possible with both IPv4 and IPv6, and the first transmission unit transmits a search message, the first transmission unit is: The search message is transmitted with priority given to the location information registered in the second routing table over the first routing table. As a result, the search message is transmitted in preference to the IPv6 routing table that has a large number of addresses and does not require NAT traversal processing, thereby reducing the number of processing steps for data acquisition.

  According to the sixth aspect of the present invention, the protocol acquisition unit acquires both IPv4 and IPv6. When the node device that has received the control message by the receiving unit can communicate with both IPv4 and IPv6, the first transmitting unit transmits the message received by the receiving unit to the node device that is the transmission source of the received message. Send to a protocol different from the protocol that can communicate. As a result, even a node device that can communicate only with either IPv4 or IPv6 can relay a message for controlling the information communication system by the node device that can communicate with both IPv4 and IPv6.

  According to the seventh aspect of the present invention, the node device includes an acquisition unit that acquires content corresponding to the search message via a different protocol. In addition, the node device includes a relay unit that relays the content acquired by the acquisition unit to the node device that is the transmission source of the message received by the reception unit. As a result, even a node device that can communicate only with either IPv4 or IPv6 can relay and acquire data with a node device that can communicate with both IPv4 and IPv6.

  According to the eighth aspect of the present invention, the first table acquisition step includes at least a part of node devices capable of communicating with IPv4 when the determination step determines that the protocol acquired by the node device is IPv4. The node device acquires a first routing table in which location information indicating the location on the network of the node devices participating in the first overlay network is registered. The second table acquisition step includes a second overlay configured by at least a part of node devices communicable with IPv6 when the determination step determines that the protocol acquired by the node device is IPv6. The node device acquires a second routing table in which the location information of the node device participating in the second overlay network is registered. The first transmission step transmits a message for controlling the information communication system to the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the node device. As a result, even in a network environment in which IPv4 and IPv6 coexist, the P2P system can be operated using the first routing table and the second routing table.

  According to the ninth aspect of the present invention, in the first table acquisition step, when it is determined in the determination step that the protocol acquired by the node device is IPv4, at least a part of the node device capable of communicating with IPv4. The node device acquires a first routing table in which location information indicating the location on the network of the node devices participating in the first overlay network is registered. The second table acquisition step includes a second overlay configured by at least a part of node devices communicable with IPv6 when the determination step determines that the protocol acquired by the node device is IPv6. The node device acquires a second routing table in which the location information of the node device participating in the second overlay network is registered. The first transmission step transmits a message for controlling the information communication system to the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the node device. As a result, even in a network environment in which IPv4 and IPv6 coexist, the P2P system can be operated using the first routing table and the second routing table.

It is a figure which shows an example of the connection aspect of each node apparatus in the content distribution storage system S in this embodiment. It is an example of the 1st routing table which a node apparatus memorizes. It is a conceptual diagram which shows an example of ID space of DHT. It is a conceptual diagram which shows an example of the production | generation procedure of the 1st routing table at the time of participating in the content distribution storage system S. It is a conceptual diagram which shows the transfer outline | summary of the participation message in the 1st routing table preparation procedure. It is a block diagram which shows the electric constitution of node apparatus Tm-n of this embodiment. It is a flowchart which shows the process sequence of the main operation | movement in node apparatus Tm-n. It is a flowchart which shows the process sequence of the routing table production | generation process in node apparatus Tm-n. It is a flowchart which shows the process sequence of the 1st message process in node apparatus Tm-n. It is a flowchart which shows the process sequence of the download process in node apparatus Tm-n. It is a flowchart which shows the process sequence of the 2nd message process in node apparatus Tm-n.

[Best Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the best embodiment of the invention will be described with reference to the drawings. The embodiment described below is an embodiment when the present invention is applied to a content distributed storage system.

[Outline configuration of distributed content storage system]
First, with reference to FIG. 1, a schematic configuration of the content distributed storage system S in the present embodiment will be described. FIG. 1 is a diagram illustrating an example of a connection mode of each node device in the content distributed storage system S according to this embodiment.

  As shown in FIG. 1, the content distribution storage system S is composed of a plurality of node devices Tm-n (n = 1, 2, 3,...). The plurality of node devices Tm-n can communicate with each other via the network NW. This network NW is a real-world communication network. For example, the Internet.

The network NW is a network for interconnecting the base networks NLm. This network NW is, for example, the Internet or WAN (Wide Area Network).
) Etc. The network NW is, for example, IX (Internet Exchange), IS
It is constructed by P (Internet Service Provider), DSL (Digital Subscriber Line) line provider apparatus, FTTH (Fiber To The Home) line provider apparatus, communication line, and the like. The network NW may be a network dedicated to the content distributed storage system S.

  In the present embodiment, one or more base networks NLm are formed in the network NW. In addition, a plurality of node devices Tm-n are connected to each base network NLm. Each base network NLm is a network constructed in the site of the base m. The bases include, for example, a company, a school, a hospital, and a cram school. This base network NLm is constructed by a LAN or the like, for example. Alternatively, the base network NLm may be a network constructed by interconnecting a plurality of LANs. In this case, the plurality of LANs are connected via a network device such as a router. An example of a network in which a plurality of LANs are interconnected is CAN (Campus Area Network). A firewall FW or a broadband router BR is connected to each base network NLm. The firewall FW or the broadband router BR is a communication device that enables communication between a node device connected in the base and a node device other than the node device connected to the base. Since the firewall FW or the broadband router BR is publicly known, detailed description thereof is omitted. Which of the firewall FW and the broadband router BR is installed at the base is arbitrarily determined for each base. The base network NLm of this embodiment is, for example, a LAN (Local Area Network).

  In addition, a server device such as an input server and a portal server is connected to the network NW. The input server and the portal server are not particularly shown.

  In the content distributed storage system S having such a configuration, the functional outline of each device as a component is as follows. The input server is a server device that inputs content data to a first overlay network PW or a second overlay network PL described later. The input server is not shown. Here, the input of content data refers to placing content data in a state where it can be acquired from the node device Tm-n. The content data is referred to as “content”.

  The portal server transmits a Web page to the node device Tm-n in response to a request from the node device Tm-n. The Web page transmitted by the portal server constitutes a Web site that distributes moving image data as an example of content. The portal server is not shown.

  The node device Tm-n is a terminal device used by a user at the base m. The node device Tm-n acquires a Web page from a Web server such as a portal server, and displays the acquired Web page on the screen. The node device Tm-n acquires and stores content from other node devices Tm-n. Further, the node device Tm-n reproduces content such as moving image data.

  In the content distributed storage system S of the present embodiment, an overlay network for content distribution is constructed. The overlay network is an overlay network constructed on the network NW. In other words, the overlay network is a logical network generated on a physical network. The overlay network is realized by a specific algorithm, for example, an algorithm using a distributed hash table. Hereinafter, the distributed hash table is referred to as “DHT (Distributed Hash Table)”. Note that a routing table using DHT is known in Japanese Patent Application Laid-Open No. 2006-197400.

  In this embodiment, there are two types of overlay networks. As shown in FIG. 2, a first overlay network PW and a second overlay network PL. The first overlay network PW is composed of any node device that can communicate with IPv4. Further, the second overlay network PL is configured by any of node devices that can communicate with IPv6. The node device according to the present embodiment includes a node device that can communicate only with IPv4, a node device that can communicate only with IPv6, and a node device that can communicate with both IPv4 and IPv6. In the example of FIG. 1, the node device T1-1, the node device T1-2, the node device T2-1, the node device T3-1, the node device T4-1, and the node device T5-1 are IPv4. Can communicate with each other. Therefore, the first overlay network PW communicates with the node device T1-1, the node device T1-2, the node device T2-1, and the IPv4 of the node device T3-1, the node device T4-1, the node device T5-1, and the like. It is composed of possible node devices. In the example of FIG. 1, the node device T1-4, the node device T2-4, the node device T2-5, the node device T3-1, and the node device T4-1 can communicate with each other by IPv6. . Therefore, the second overlay network PL is configured by node devices that can communicate with IPv6 such as the node device T1-4, the node device T2-4, the node device T2-5, the node device T3-1, and the node device T4-1. The

  Details of the method of generating the first overlay network PW or the second overlay network PL will be described later. Using the first overlay network PW or the second overlay network PL, port forwarding is set in the broadband router BR and the firewall FW so that each node device Tm-n can perform communication in a peer-to-peer manner. For example, in the case of a broadband router BR, it is preferable to set port forwarding automatically using a UPnP (Universal Plug and Play) function or the like.

[Method for generating first overlay network and second overlay network]
Hereinafter, a method for generating the first overlay network PW and the second overlay network PL will be described. In the first overlay network PW, the first routing table of DHT is used. In the second overlay network PL, the second routing table of DHT is used.

  In the present embodiment, the content distributed storage system S includes a first contact node that can communicate with IPv4 and a second contact node that can communicate with IPv6. The contact node is a node device that first transmits a message when each node device Tm-n participates in the overlay network. For example, the node device Tm-n that can communicate with IPv4 transmits a participation message to the first contact node. Further, the node device Tm-n that can communicate with Ipv6 transmits a participation message to the second contact node. The first contact node and the second contact node that have received the participation message execute a participation process. First, the routing table of this embodiment will be described in detail.

  FIG. 2 is an example of a first routing table stored in the node device Tm-n. FIG. 3 is a conceptual diagram illustrating an example of a DHT ID space. 2 and 3, for convenience of explanation, the bit length of the node ID is 2 bits × 3 digits = 6 bits. Therefore, each digit is represented by a quaternary number (integer of 0 to 3) represented by 2 bits. A bit length longer than 2 bits may be used for each digit. For example, each digit may be represented by 4 bits and represented by a hexadecimal number of 0 to f.

  As shown in FIG. 2, the first routing table is composed of a plurality of levels from level 1 (first stage) to level 3 (third stage). Node information is registered in each area. The node information includes a node ID and an IP address and a port number of the node device corresponding to the node ID. In the case of the example of FIG. 2, a node ID “002” and the IP address and port number of the node device T2-1 corresponding to the node ID “002” are associated with the 0XX area of level 1 It is registered as information.

Each area in each of levels 1 to 3 shown in FIG. 2 is an area determined by dividing the node ID space. FIG. 3 is a conceptual diagram in which each area is determined using a node ID. The node ID space is configured by a three-digit number in which each digit is represented by a quaternary number (an integer from 0 to 3). As shown in FIG. 3, as a level 1 area, the node ID space is divided into four (due to quaternary numbers). Specifically, the level 1 area is divided into a 0XX area, a 1XX area, a 2XX area, and a 3XX area. The area of 0XX is' 0
This is an area where node IDs of 00 'to' 033 'exist. The 1XX area is an area where node IDs “100” to “133” exist. The 2XX area is '200' to '233'
This is an area where node IDs exist. The 3XX area is an area where node IDs “300” to “333” exist.

In level 2, the level 1 area is further divided into four (due to quaternary numbers). That is, each area from 0XX to 3XX is further divided into four. The 0XX area, the 1XX area, the 2XX area, and the 3XX area are each divided into four. For example, in the case of a 1XX area, an area where node IDs “100” to “103” exist is divided as a 10X area. In the case of an 11X area, an area where node IDs “110” to “113” exist is divided as an 11X area. In the case of a 12X area, '120' to '12
The area where the 3 ′ node ID exists is divided as a 12 × area. In the case of the 13X area, the area where the node IDs “130” to “133” exist is divided as the 13X area.

  Hereinafter, a case where the node ID of the node device Tm-n is “122” will be described as an example. As shown in FIG. 2, the area of 1XX in level 1 of the routing table is an area where the node ID of the node device T1-2 exists. Therefore, in the example of FIG. 2, the node ID of the node device T1-2 itself and the IP address or port number are registered in the level 1 1XX area. In the present embodiment, the node ID and IP address or port number of the node device T1-2 itself are registered, but the node ID and IP address or port number are not registered because they are the node device T1-2 itself. May be. Node IDs of other arbitrary node devices and IP addresses or port numbers are registered in areas where the node IDs of the node devices T1-2 do not exist. When the node ID of the node device T1-2 is “122”, the areas where the node ID of the node device T1-2 does not exist are the 0XX area, the 2XX area, and the 3XX area.

  Further, the 12X area in the level 2 of the routing table is an area where the node ID of the node device T1-2 exists. Therefore, the node ID of the node device T1-2 itself and the IP address or port number are registered in the level 2 12X area. In the area where the node ID of the node device T1-2 does not exist, the node ID of any other node device and the IP address or port number are registered in the same manner as in level 1.

Further, the level 3 of the routing table has a node ID of '12 as shown in FIG.
0 'to' 123 '. Therefore, the node device T1-2 is located in the area of level 3 122.
The node ID of itself and the IP address or port number are registered. In the present embodiment, the node ID and IP address or port number of the node device T1-2 itself are registered. However, the IP address or port number does not need to be registered because it is the node device T1-2 itself. .

In the example of FIGS. 2 and 3, the bit length of the node ID is 3 digits × 2 bits. For example, when the bit length of the node ID is 16 digits × 4 bits, a table for 16 levels is required. As shown in FIGS. 2 and 3, in the first routing table in the present embodiment, the area becomes narrower as the numerical value of the level becomes larger. Such a first routing table is generated, for example, when a non-participating node device participates in the content distributed storage system S. In this embodiment, participating in an overlay network means operating in a state where various messages can be transmitted to and received from other node devices based on a routing table using DHT. As a result, each node device can transmit and receive messages to and from other node devices via the overlay network. Here, transmission / reception of a message via the overlay network means transmission / reception of a message between node devices participating in the overlay network. The DHT routing table is well known in, for example, Japanese Patent Application Laid-Open No. 2007-053662, and detailed description thereof is omitted. Here, with reference to FIG. 4, a procedure for generating the first routing table when participating in the distributed content storage system S will be described in detail.

  FIG. 4 is a conceptual diagram showing an example of a procedure for generating the first routing table when participating in the content distributed storage system S. Specifically, FIG. 4 is a conceptual diagram showing an overview of a participation message being transferred between the node devices Tm-n. FIG. 5 is a conceptual diagram showing an outline of transfer of a participation message in the first routing table creation procedure. Hereinafter, an example in which the non-participating node device T8-1 participates in the distributed content storage system S will be described. Note that the node device 1-4, the node device T8-1, the node device 9-1, and the node device 10-1 illustrated in FIGS. 4 and 5 are node devices that can communicate by IPv4. Hereinafter, the node ID of the non-participating node device T8-1 is “123”. In FIG. 4 and FIG. 5, “node” is described as an abbreviation of the node device. Further, “JOIN” is described as an abbreviation of the participation message.

  As shown in FIGS. 4 and 5, when a node device T8-1 that has not participated participates in the content distribution storage system S, the node device is used by using the IP address of the node device T9-1 that is the first contact node device. A participation message is transmitted at T9-1. As shown in FIG. 5, the participation message includes the node ID of the node device T8-1 that has not participated. It is assumed that the non-participating node device T8-1 knows in advance the IP address for transmitting a message to the node device T9-1 that is the first contact device. For example, when downloading software necessary to participate in the first overlay network PW or the second overlay network PL, the IP address of the node device T9-1 that is the first contact node is acquired.

The node device T9-1 that has received the participation message refers to the first routing table of the node device T9-1. Specifically, the node information registered in the level 1 table in the first routing table is referred to. The node device T9-1 returns a reply message including the node information registered in the level 1 to the node device T8-1. Furthermore, the node device T9-1 compares the node ID included in the received participation message with the node IDs of the other node devices Tm-n registered in the first routing table. One node device Tm-n is selected from the first routing table based on the comparison result. Note that the node device Tm-n registered in the first routing table is a node device capable of communicating by IPv4. For example, the node device T9-1 selects the node device T10-1 having the node ID closest to the node ID 123 included in the participation message from the first routing table. At this time, the participation message transmitted from the node device T9-1 to the node device T10-1 includes information indicating the number of table stages to be returned next. Level 2 is included in the participation message transmitted from the node device T9-1 to the node device T10-1. Also, the node device T10-1 that has received the participation message uses the first routing table as the node device T1-4 having the node ID closest to the node ID 123 included in the participation message, as in the case of the node device T9-1. Select from. At this time, the participation message transmitted from the node device T10-1 to the node device T1-4 includes information indicating the number of stages of the table to be returned next. Level 3 is included in the participation message transmitted from the node device T10-1 to the node device T1-4.

  A description will be given by using an example in which the selected node device is the node device T10-1. At this time, the participation message includes information indicating the number of steps of the table to be returned next. In the above example, level 2 is included in the participation message.

  The node device T10-1 that has received the participation message returns a reply message including node information registered in level 2 of the first routing table of the node device T10-1 to the node device T8-1. Further, the node device T10-1 transfers the participation message to the node device T1-4 selected from the first routing table. At this time, information indicating level 3 is included in the participation message as the number of steps of the table to be returned next.

  The node device T1-4 that has received the participation message returns a reply message including the node information registered in the level 3 in the first routing table of the node device T1-4 to the node device T8-1. As described above, the participation message is transferred based on the first routing table using the node ID as a key. Therefore, the data is transferred to the node device Tm-n having the node ID closest to the node ID of the non-participating node device T8-1. For example, the closest node ID is an ID that matches more higher digits, or a node ID that has the smallest difference from the compared node ID.

  And node device T8-1 produces | generates a 1st routing table using the node information contained in the reply message received from each node device. Specifically, the node information transmitted from the node device T9-1 is registered in level 1 of the first routing table of the node device T8-1. The node information transmitted from the node device T10-1 is registered in level 2 of the first routing table of the node device T8-1. The node information transmitted from the node device T1-4 is registered in level 3 of the first routing table of the node device T8-1.

  Thus, the node device T8-1 acquires the first routing table and stores it in the storage unit of the node device T8-1. Thereby, participation in the content distributed storage system S is completed. In the present embodiment, various messages such as the participation message as described above and a search request message described later include node information of a message transmission source or transfer source node device. Therefore, the node device that has received the message registers and updates the node information in the first routing table of the node device.

  The message transferred between the node devices Tm-n includes the node ID of the message transmission source, the content of the message, and the node information of the transmission source or the transfer source. The node ID of the message transmission source is the node ID of the transmission source node device Tm-n that has transmitted the message. The content of the message is “join (JOIN)”, “publish”, “query” or the like indicating the purpose of the message. “Participation” indicates a participation message. “Publish” indicates a publish message. “Query” indicates a search request message. Details of the publish message and the search request message will be described later. The node information includes a node ID of the source or transfer source node device Tm-n and an IP address or a port number. In the case of a participation message, “message content” includes information indicating that a reply of node information in the table is requested. In the case of a publish (registration) message or query, the content ID of the content to be published (registered) or queried (request) is included.

  In the example illustrated in FIG. 4, the node device T10-1 receives a participation message from the node device T9-1 that is the first contact node. Then, the node device T10-1 registers the node information of the transmission source or transfer source first contact node device T9-1 included in the participation message in the first routing table of the node device T10-1. At this time, when the node information of the first contact node device T9-1 is already registered in the routing table of the node device T10-1, the node information of the registered first contact node device T9-1 is the received node information. Updated based on

  Similarly, the node device T1-4 that has received the participation message from the node device T10-1 uses the node information of the source or transfer source node device T10-1 included in the participation message as the first routing of the node device T1-4. Register or update in the table. According to the above procedure, node information is registered or updated in the routing table.

  The second routing table is generated by the same method as the first routing table. Specifically, when the non-participating node device T8-1 participates in the content distribution storage system S, the participation message is transmitted to the second contact node device using the IP address of the second contact node device. The second contact node that has received the participation message executes processing similar to that of the first contact node. The second contact node stores a second routing table composed of node information of node devices that can communicate with IPv6. Using the second routing table, the second contact node causes the non-participating node device to acquire the second routing table in the same manner as the first contact node.

[Description of content acquisition operation]
The content distributed storage system S stores various content data replicas having different contents in a predetermined file format in a distributed manner in a plurality of node devices Tm-n. Hereinafter, the content data is referred to as “content”. A replica can be used between the node devices Tm-n. The original of each content is stored in a center server (not shown) connected to the WAN. Hereinafter, the node device Tm-n in which the content replica is stored is referred to as a “content holding node”. In the following description, the original content and the replica are referred to as content without particular distinction. Information such as a content name and content ID, which is unique identification information for each content, is added to each content described above.

  The location of the content that is distributed and stored is stored as index information by the node device Tm-n that stores the location of the content. Hereinafter, the node device Tm-n that stores the location of the content is referred to as a “root node”. The index information includes a set of node information of the node device Tm-n that stores the replica, a content ID of the content, and the like. Such a root node is determined to be a node device Tm-n having a node ID closest to the content ID, for example. The node ID closest to the content ID is, for example, a node ID that matches the content ID more frequently with the upper digits.

  When a user of a certain node device Tm-n wants to acquire desired content, the node device Tm-n that desires to acquire the content generates a message. Hereinafter, the node device Tm-n that the user desires to acquire content is referred to as a “user node”. This message is a search request message including the content ID of content desired to be acquired, node information of the user node, and the like. The search request message is also a message for searching for a content holding node. The search request message described above is sent to another node device Tm-n according to the first routing table or the second routing table of the DHT stored in the user node. That is, the user node sends a search request message toward the root node of the content. Thereby, the search request message finally reaches the root node by DHT routing using the content ID as a key. In the present embodiment, the search request message includes a first search request message and a second search request message. Details of the first search request message and the second search request message will be described later.

  The root node that has received the search request message obtains index information corresponding to the content ID included therein from the index information cache. Then, the root node returns a search response message including the acquired index information to the user node that is the transmission source of the search request message. The user node that has acquired the index information transmits a content request message to the content holding node based on the IP address and port number of the content holding node included in the index information. The content request message includes the content ID of the content desired to be acquired. The content holding node that has received the content request message acquires content corresponding to the content ID included in the content request message from the content cache area. Then, the content holding node transmits a content request response message including the acquired content to the user node. In this way, the user node can download (acquire) content.

  Further, when the user node acquires and stores the content from the content holding node, the stored user node generates a publish message. The publish message is a message for informing the root node that the content has been saved. The publish message includes the content ID of the content and the node information of the node device Tm-n that stores the content. The publish message is sent toward the root node. As a result, the publish message reaches the root node by the first routing table or the second routing table of the DHT using the content ID as a key, like the search request message. Then, the root node receives the publish message. The root node stores index information including a set of node information and content ID included in the publish message in the index information cache area. In this way, the user node becomes a new content holding node that holds the content of the content.

  In the present embodiment, when the node device Tm-n can communicate with both IPv4 and IPv6, the publish message is transmitted to the destinations described in the first routing table and the second routing table. On the other hand, when the node device Tm-n can communicate only with IPv4, the publish message is transmitted to the destination described in the first routing table. When the node device Tm-n can communicate only with IPv6, the publish message is transmitted to the destination described in the second routing table.

  In this embodiment, there are two types of search request messages: a first search request message and a second search request message. The first search request message is a search request message transmitted by a node device that can communicate with both IPv4 and IPv6. On the other hand, the second search request message is a search request message transmitted by a node device that can communicate with either IPv4 or IPv6.

  The first search request message of this embodiment includes node information, content ID, and version information. The node information included in the first search request message is node information of the node device that is the transmission source of the first search request message. The content ID included in the first search request message is the content ID of the content requested to be searched by the first search request message. The version information included in the first search request message is version information indicating IPv4 and IPv6, which are protocols that can be communicated with the node device that is the transmission source of the first search request message.

  The second search request message of this embodiment includes node information, content ID, and version information. The node information included in the second search request message is node information of the node device that is the transmission source of the second search request message. The content ID included in the second search request message is the content ID of the content requested to be searched by the second search request message. The version information included in the second search request message is version information indicating either IPv4 or IPv6, which is a protocol communicable with the node device that is the transmission source of the second search request message.

  Hereinafter, a method for transmitting the first search request message will be described. When the first search request message is transmitted, it is first transmitted to the destination described in the second routing table. If the search response message is not received during the predetermined period, the first search request message is transmitted to the destination described in the first routing table. This is because the node device that can communicate with IPv6 is given priority over the node device that can communicate with IPv4 as the content acquisition destination. By this processing, it is possible to download and upload content from a node device that can communicate with IPv6 without causing a problem of exceeding NAT (Network Address Translation). Also, the first search request message is transmitted to both the first routing table and the second routing table, and the node device that can communicate with IPv6 is selected from the received response message, and the content is downloaded and uploaded. May be.

  Hereinafter, a method for transmitting the second search request message will be described. The second search request message is transmitted by a node device that can communicate with either IPv4 or IPv6. The node device that has received the second search request message may be able to communicate with either IPv4 or IPv6. In this case, the first routing table or the second routing table used for transmitting the second search request message is determined based on a protocol with which the node device that has received the second search request message can communicate. The second search request message is transmitted or transferred to the node device registered in the determined first routing table or second routing table.

  On the other hand, the node device that has received the second search request message may be a node device that can communicate with both IPv4 and IPv6. In this case, the second search request message is transmitted or transferred to a node device that can communicate with a protocol different from the protocol with which the node device that is the transmission source of the second search request message can communicate.

  Specifically, when the transmission source of the second search request message is a node device that can communicate with IPv4, the second search request message is sent to the second routing table by the node device that can communicate with both IPv4 and IPv6. Is relayed to the destination. That is, the second search request message is transmitted or transferred to a node device that can communicate with IPv6. Further, when the second search request message is transmitted by a node device that can communicate with IPv6, the second search request message is relayed to the destination of the first routing table by the node device that can communicate with both IPv4 and IPv6. Is done. That is, the second search request message is transmitted or transferred to a node device that can communicate with IPv4. Thereby, even when the desired content cannot be searched by the second search request message, the node device can communicate with a protocol different from the protocol with which the node device to which the second search request message is transmitted can communicate. To the second search request message. As a result, it is possible to acquire content from a node device that can communicate with a protocol different from the protocol with which the node device to which the second search request message is transmitted can communicate.

  In the present embodiment, when a second search request message is transmitted by a node device that can communicate with both IPv4 and IPv6, a transfer flag may be included in the second search request message to be transferred. The transfer flag is a flag indicating that the second search request message has been transferred to a different protocol by a node device capable of communicating with both IPv4 and IPv6. In addition to the transfer flag, information indicating that the second search request message has been transferred to a different protocol may be used. When a node device that can communicate with both IPv4 and IPv6 receives a message including a transfer flag, the node device that has received the second search request message transfers the second search request message to a different protocol. It is not necessary. This is to avoid that the second search request message continues to be transferred to a different protocol and cannot be sufficiently searched using the first routing table or the second routing table. By including the transfer flag in the second search request message, it is possible to prevent unnecessary transfer of the second search request message between different protocols.

[Electrical configuration of node equipment]
Next, an electrical configuration of the node device Tm-n will be described with reference to FIG. FIG. 6 is a block diagram illustrating an electrical configuration of the node device Tm-n according to the present embodiment. As illustrated in FIG. 6, the node device Tm-n according to the present embodiment includes a CPU 1 that controls the node device Tm-n. An HDD 2, a RAM 3, a decoder unit 4, and a communication unit 9 are electrically connected to the CPU 1. The storage means such as the HDD 2 and the RAM 3 and the CPU 1 constitute a computer of the node device Tm-n. The CPU 1, HDD 2, RAM 3, decoder unit 4, and communication unit 9 are connected to each other via a bus. As the node device Tm-n, a personal computer, an STB (Set Top Box), or the like is applicable.

  The HDD 2 includes a program storage area 21, an address information storage area 27, a first routing table storage area 28, a second routing table storage area 29, and a version information storage area 30. The program storage area 21 includes a main operation program storage area 22, a routing table generation program storage area 23, a first message processing program storage area 24, a second message processing program storage area 25, and a download processing program storage area 26. Including.

  The main operation program storage area 22 stores a main operation program of the node device Tm-n. The main operation program performs main operation processing of the node device Tm-n. The routing table generation program storage area 23 stores a routing table generation program. The routing table generation program is a program in which the node device Tm-n generates the first routing table or the second routing table. The first message processing program storage area 24 stores a first message processing program. The first message processing program is a program in which the node device Tm-n processes the first message. The second message processing program storage area 25 stores a second message processing program. The second message processing program is a program in which the node device Tm-n processes the second message. The download processing program storage area 26 stores a download processing program. The download processing program performs download processing of the node device Tm-n.

  The main operation program, the routing table generation program, the first message processing program, the second message processing program, and the download processing program may be downloaded from a predetermined server on the network NW, for example. Alternatively, it may be recorded on a recording medium such as a CD-ROM and read via a drive of the recording medium.

  The address information storage area 27 stores the IP address of the first contact node or the second contact node. The address information storage area 27 stores the IP address of at least one of the first contact node and the second contact node acquired by the node device Tm-n.

  The first routing table storage area 28 stores the generated first routing table. The second routing table storage area 29 stores the generated second routing table.

  The version information storage area 30 stores version information. The version information is a protocol with which the node device Tm-n can communicate. When the node device Tm-n can communicate with both IPv4 and IPv6, version information indicating IPv4 and IPv6 is stored in the version information storage area 30. When the node device Tm-n can communicate with IPv4, version information indicating IPv4 is stored in the version information storage area 30. When the node device Tm-n can communicate with IPv6, version information indicating IPv6 is stored in the version information storage area 30. The version information of this embodiment may be set in advance in each node device Tm-n, or may be acquired by being directly connected from another device. Further, the version information may be acquired from another device via the network NW. The version information storage area 30 of this embodiment is an example of the protocol acquisition unit of the present invention.

  The RAM 3 includes a content data temporary storage area 31. The content data temporary storage area 31 temporarily stores content data transmitted and received between the node devices Tm-n. The content data temporary storage area 31 of this embodiment is an example of the acquisition unit of the present invention. The content data transmitted / received by the content distributed storage system S may be stored in either the HDD 2 or the RAM 3. The HDD 2 and the RAM 3 of this embodiment are an example of the storage unit of the present invention. The communication unit 9 performs communication control of information with the node device Tm-n or an external device through the network NW.

  The node device Tm-n performs a reception process for receiving content data transmitted in response to a request via the communication unit 9. The content data of this embodiment is packetized and transmitted. Each packet is received through the communication unit 9 and temporarily stored in the content data temporary storage area 31 of the RAM 3. The content data temporarily stored in this way is read from the content data temporary storage area 31 and reproduced and output through the decoder unit 4, the video processing unit 5, the audio processing unit 7, the display 6, and the speaker 8. The Alternatively, the content data stored in the content data temporary storage area 31 may be read from the content data temporary storage area 31 and stored in the HDD 2. Alternatively, the content data may be stored directly in the HDD 2 without going through the RAM 3. Thereafter, content data is read from the HDD 2 in accordance with an operation instruction from the user via the input unit 10. The read content data is reproduced and output through the decoder unit 4, the video processing unit 5, the audio processing unit 7, the display 6, and the speaker 8. Thereby, the user can view the content.

[Description of operation of node device Tm-n of this embodiment]
The operation and action of the node device Tm-n according to the present embodiment having the above-described configuration will be described with reference to the accompanying drawings. First, operation | movement and an effect | action of node apparatus Tm-n are demonstrated with reference to an accompanying drawing. FIG. 7 is a flowchart showing a processing procedure of the main operation in the node device Tm-n. The main operation is performed when an external power source such as a commercial power source is connected to the node device Tm-n via a power source or an outlet, and the installed P2P software program is executed by the CPU 1. The processing shown below is processed by the CPU 1.

  In step S101, routing table generation processing is executed. In the routing table generation process, at least one of the first routing table and the second routing table is generated based on a protocol with which the node device Tm-n executing the main operation process can communicate.

  In step S102, it is determined whether or not the node device Tm-n executing the main operation process can be connected to both IPv4 and IPv6. Based on the version information stored in the version information storage area 30, it is determined whether or not connection to both IPv4 and IPv6 is possible. If it is determined that connection to both IPv4 and IPv6 is possible (step S102: Yes), step S103 is executed. If it is not determined that connection to both IPv4 and IPv6 is possible (step S103: No), step S104 is executed. The computer of this embodiment and step S102 are an example of the determination unit of the present invention. Moreover, step S102 of this embodiment is an example of a determination step.

  In step S103, the first message process is executed. Details of the first message processing will be described later.

  In step S104, the second message process is executed. Details of the second message processing will be described later.

  In step S105, it is determined whether or not the power switch is turned off by the user. If the power switch is not turned off (step S105: No), step S102 is executed again. When the power switch is turned off (step S105: Yes), the main operation process is terminated.

(Routing table generation process)
FIG. 8 is a flowchart showing the routing table generation processing operation. In step S201, it is determined whether or not the node device Tm-n can communicate with IPv4. Whether or not communication is possible with IPv4 is determined by whether or not version information indicating that connection with IPv4 is possible is stored in the version information storage area 30. When version information indicating that connection with IPv4 is possible is stored, it is determined that communication is possible with IPv4. If it is not determined that version information indicating that connection with IPv4 is possible is stored, it is not determined that communication is possible with IPv4. When it is determined that communication is possible with IPv4 (step S201: Yes), step S202 is executed. When it is not determined that communication is possible with IPv4 (step S201: No), step S204 is executed.

  In step S202, a participation message is transmitted to the first contact node. The IP address of the first contact node is stored in the address information storage area 27. The computer of this embodiment and step S202 are an example of the 2nd transmission part of this invention.

  In step S203, a first routing table is generated. The node device that has received the participation message transmitted in step S202 transmits node information that can be registered in the first routing table. The transmitted node information is received in step S203. A first routing table is generated based on the node information received in step S203. The generated first routing table is stored in the first routing table storage area 28. The computer of this embodiment and step S203 are an example of the 1st table acquisition part of this invention. Moreover, step S203 of this embodiment is an example of the first table acquisition step of the present invention.

  In step S204, it is determined whether or not the node device Tm-n can communicate with IPv6. Whether or not communication is possible with IPv6 is determined by whether or not version information indicating that connection with IPv6 is stored in the version information storage area 30. When version information indicating that connection with IPv6 is possible is stored, it is determined that communication is possible with IPv6. If it is not determined that version information indicating that connection with IPv6 is possible is not stored, it is not determined that communication is possible with IPv6. When it is determined that communication is possible with IPv6 (step S204: Yes), step S205 is executed. If it is not determined that communication is possible with IPv6 (step S204: No), the routing table generation process is terminated.

  In step S205, a participation message is transmitted to the second contact node. The IP address of the second contact node is stored in the address information storage area 27. The computer of this embodiment and step S205 are an example of the 2nd transmission part of this invention.

  In step S206, a second routing table is generated. The node device that has received the participation message transmitted in step S205 transmits node information that can be registered in the second routing table. The transmitted node information is received in step S206. A second routing table is generated based on the node information received in step S206. The generated second routing table is stored in the second routing table storage area 29. The computer of this embodiment and step S206 are an example of the 2nd table acquisition part of this invention. Moreover, step S206 of this embodiment is an example of the second table acquisition step of the present invention.

(First message processing)
FIG. 9 is a flowchart showing the first message processing operation. First, in step S301, it is determined whether or not a publish message is transmitted. It is determined whether or not the message transmitted by the node device Tm-n is a publish message. When it is determined that a publish message is transmitted (step S301: Yes), step S302 is executed. When it is not determined that the publish message is transmitted (step S301: No), step S304 is executed.

  In step S302, a publish message is transmitted according to the first routing table. A publish message is transmitted toward the node device registered in the first routing table. The computer of this embodiment and step S302 are an example of the 1st transmission part of this invention. Moreover, step S302 of this embodiment is an example of the first transmission step of the present invention.

  In step S303, a publish message is transmitted according to the second routing table. A publish message is transmitted toward the node device registered in the second routing table. The computer of this embodiment and step S303 are an example of the 1st transmission part of this invention. Moreover, step S303 of the present embodiment is an example of a first transmission step of the present invention.

  In step S304, it is determined whether or not the first search request message is transmitted. It is determined whether or not the message transmitted by the node device Tm-n is the first search request message. When it is determined that the first search request message is transmitted (step S304: Yes), step S305 is executed. If it is not determined that the first search request message is transmitted (step S304: No), step S306 is executed.

  In step S305, download processing is executed based on the first search request message transmitted in step S304. Details of the download process will be described later.

  In step S306, it is determined whether a first search request message has been received. It is determined whether or not a first search request message has been received from another node device. If it is determined that the first search request message has been received (step S306: Yes), step S307 is executed. If it is not determined that the first search request message has been received (step S306: No), step S310 is executed.

  In step S307, it is determined whether the content corresponding to the first search request message is stored. The first search request message includes a content ID to be searched. It is determined whether or not the node device Tm-n that has received the first search request message stores content corresponding to the content ID to be searched. If it is determined that the content corresponding to the first search request message is stored (step S307: Yes), step S308 is executed. If it is not determined that the content corresponding to the first search request message is stored (step S307: No), step S309 is executed.

  In step S308, the content determined to be stored in step S307 is transmitted to the transmission source of the first search request message. The first search request message includes the IP address of the node device that is the transmission source of the first search request message. Therefore, the content corresponding to the first search request message is transmitted to the transmission source of the first search request message.

  In step S309, the first search request message received in step S306 is transferred. Specifically, the first search request message is transferred to the node devices registered in the first routing table and the second routing table.

  In step S310, it is determined whether a second search request message has been received. It is determined whether or not a second search request message has been received from another node device. If it is determined that the second search request message has been received (step S310: Yes), step S311 is executed. If it is not determined that the first search request message has been received (step S310: No), the first message processing is terminated. The computer of this embodiment and step S310 are an example of the receiving part of this invention.

  In step S311, the second search request message is transmitted to the node device having a different protocol. The second search request message of this embodiment includes version information of the node device that is the transmission source of the second search request message. In addition, the node device that executes Step S311 is a node device that can communicate with both IPv4 and IPv6. Therefore, in step S311, when the second search request message is transmitted by a node device that can communicate with IPv4, the second search request message is transmitted to the node device registered in the second routing table. That is, the second search request message is transmitted to a node device that can communicate with IPv6. On the other hand, when the second search request message is transmitted by a node device that can communicate with IPv6, the second search request message is transmitted to the node device registered in the first routing table. That is, the second search request message is transmitted to the node device that can communicate with IPv4. In the case of step S311, the node information of the node device that is the transmission source of the second search request message is changed to the node information of the node device that executed step S311. Further, the node information after the change in step S311 and the node information before the change are associated with each other and temporarily stored in a predetermined storage area of the RAM 3. If the transfer flag is included in the second search request message, it is determined in step S311 whether or not the transfer flag is included in the received second search request message. If it is determined that the transfer flag is included, the second search request message is not transmitted to a different protocol in step S311. On the other hand, if it is not determined that the transfer flag is included, the second search request message is transmitted to a different protocol in step S311. When the second search request message is transmitted to a different protocol in step S311, a transfer flag is included in the second search request message.

  In step S312, it is determined whether or not a search response message has been received within a predetermined period after step S311 is executed. The predetermined period is counted by a timer provided in the node device Tm-n. Note that the timer is not shown. When it is determined that the search response message has been received within the predetermined period (step S312: Yes), step S313 is executed. If it is not determined that the search response message has been received within the predetermined period (step S312: No), the first message process is terminated.

  In step S313, the content is relayed. Specifically, the content corresponding to the second search request message transmitted to the different protocol in step S311 is received and acquired. For example, when the second search request message received in step S310 is transmitted by a node device that can communicate with IPv4, the content is received from the node device that can communicate with IPv6. The received content is temporarily stored in the content data temporary storage area 31. Then, based on the pre-change node information and the post-change node information stored in the predetermined storage area of the RAM 3 in step S311, the received content is relayed to the node device that is the transmission source of the second search request message. Is done. The content to be relayed is the content temporarily stored in the content data temporary storage area 31 in step S313. As a result, the content stored by the node device that can communicate with IPv6 can be relayed to the node device that can communicate with IPv4. On the other hand, when the second search request message received in step S310 is transmitted by a node device that can communicate with IPv6, content is received from the node device that can communicate with IPv4. Then, based on the pre-change node information and the post-change node information stored in the predetermined storage area of the RAM 3 in step S311, the received content is relayed to the node device that is the transmission source of the second search request message. Is done. As a result, the content stored by the node device that can communicate with IPv4 can be relayed to the node device that can communicate with IPv6. The computer of this embodiment and step S313 are an example of the relay unit of the present invention.

(Download process)
FIG. 10 is a flowchart showing the download processing operation. In step S401, the first search request message is transmitted based on the second routing table. The first search request message is transmitted toward the node device registered in the second routing table. The computer of this embodiment and step S401 are an example of the 1st transmission part of this invention. Moreover, step S401 of this embodiment is an example of the first transmission step of the present invention.

  In step S402, it is determined whether a search response message is received within a predetermined period. The search response message is a message in response to the first search request message transmitted in step S401. When the content searched by the first search request message is found, a search response message is received. If it is determined that the search response message is received within the predetermined period (step S402: Yes), step S405 is executed. If it is not determined that the search response message has been received within the predetermined period (step S402: No), step S403 is executed.

  In step S403, the first search request message is transmitted based on the first routing table. The first search request message is transmitted toward the node device registered in the first routing table. The computer of this embodiment and step S403 are an example of the first transmission unit of the present invention. Moreover, step S403 of the present embodiment is an example of a first transmission step of the present invention.

  In step S404, it is determined whether a search response message is received within a predetermined period. The search response message is a message that responds to the first search request message transmitted in step S403. When the content searched by the first search request message is found, a search response message is received. When it is determined that the search response message has been received within the predetermined period (step S404: Yes), step S405 is executed. If it is not determined that the search response message has been received within the predetermined period (step S404: No), step S407 is executed.

  In step S405, a content acquisition destination is determined based on the search response message received in step S402 or step S404. The search response message includes node information of the content holding node device. That is, the search response message includes the index information described above. The content acquisition destination is determined based on the node information of the content holding node included in the search response message.

  In step S406, the content is downloaded from the acquisition source determined in step S405.

  In step S407, an error is notified. This is a notification indicating that the content corresponding to the first search request message could not be searched.

(Second message processing)
FIG. 11 is a flowchart showing the second message processing. First, in step S501, it is determined whether a publish message is transmitted. It is determined whether or not the message transmitted by the node device Tm-n is a publish message. When it is determined that the publish message is transmitted (step S501: Yes), step S502 is executed. If it is not determined that the publish message is transmitted (step S501: No), step S503 is executed.

  In step S502, a routing table corresponding to the version information of the node device Tm-n is determined. Then, a publish message is transmitted to the node device Tm-n registered in the determined routing table. For example, when the version information of the node device Tm-n is IPv4, the first routing table is determined. On the other hand, when the version information of the node device Tm-n is IPv6, the second routing table is determined. A publish message is transmitted to the node device registered in the determined first routing table or second routing table. The computer of this embodiment and step S502 are an example of the 1st transmission part of this invention. Moreover, step S502 of this embodiment is an example of the first transmission step of the present invention.

  In step S503, it is determined whether a second search request message is transmitted. It is determined whether or not the message transmitted by the node device Tm-n is the second search request message. When it is determined that the second search request message is transmitted (step S503: Yes), step S504 is executed. When it is not determined that the second search request message is transmitted (step S503: No), step S508 is executed.

  In step S504, it is determined whether or not a search response message has been received within a predetermined period after the second search request message is transmitted in step S503. The predetermined period is counted by a timer provided in the node device Tm-n. Note that the timer is not shown. When it is determined that the search response message has been received within the predetermined period (step S504: Yes), step S505 is executed. If it is not determined that the search response message has been received within the predetermined period (step S504: No), step S507 is executed.

  In step S505, the content acquisition destination is determined based on the search response message received in step S504. The search response message includes node information of the content holding node device. That is, the search response message includes the index information described above. The content acquisition destination is determined based on the node information of the content holding node included in the search response message.

  In step S506, the content is downloaded from the acquisition source determined in step S505.

  In step S507, an error is notified. This is a notification indicating that the content corresponding to the second search request message could not be searched.

  In step S508, it is determined whether another message is transmitted. The other message is a control message for controlling the content distributed storage system S, for example. When it is determined that another message is transmitted (step S508: Yes), step S509 is executed. When it is not determined that another message is transmitted (step S508: No), step S510 is executed.

  In step S509, a routing table corresponding to the version information of the node device Tm-n is determined. Then, the other message is transmitted to the node device Tm-n registered in the determined routing table. For example, when the version information of the node device Tm-n is IPv4, the first routing table is determined. On the other hand, when the version information of the node device Tm-n is IPv6, the second routing table is determined. The other message is transmitted to the node device registered in the determined first routing table or second routing table. The computer of this embodiment and step S509 are an example of the first transmission unit of the present invention. Moreover, step S509 of the present embodiment is an example of a first transmission step of the present invention.

  In step S510, it is determined whether a second search request message has been received. It is determined whether or not a second search request message has been received from another node device. If it is determined that the second search request message has been received (step S510: Yes), step S511 is executed. If it is not determined that the first search request message has been received (step S510: No), the second message processing is terminated.

  In step S511, it is determined whether content corresponding to the second search request message is stored. It is determined whether or not the content corresponding to the content ID included in the second search request message is stored in the storage unit of the node device Tm-n. If it is determined that the content corresponding to the second search request message is stored (step S511: Yes), step S512 is executed. If it is not determined that the content corresponding to the second search request message is stored (step S511: No), step S513 is executed.

  In step S512, the content determined to be stored in step S511 is transmitted to the transmission source of the second search request message. The second search request message includes the IP address of the node device that is the source of the second search request message. Therefore, the content corresponding to the second search request message is transmitted to the transmission source of the second search request message.

  In step S513, the second search request message determined to have been received in step S510 is transferred. The second search request message of this embodiment includes version information of the node device that is the transmission source of the second search request message. Therefore, the routing table corresponding to the version information included in the second search request message is selected. The node device that executes Step S513 is a node device that can communicate only with either IPv4 or IPv6. Therefore, in step S513, when the second search request message is transmitted by a node device that can communicate with IPv4, the second search request message is transmitted to the node device registered in the first routing table. That is, the second search request message is transmitted to the node device that can communicate with IPv4. On the other hand, when the second search request message is transmitted by a node device that can communicate with IPv6, the second search request message is transmitted to the node device registered in the second routing table. That is, the second search request message is transmitted to a node device that can communicate with IPv6.

In the above embodiment, the peer-to-peer communication system using the DHT routing table is applied to the overlay network. However, the present invention is not limited to this. The present invention may be applied to other peer-to-peer communication systems or systems using overlay networks. For example, the present invention may be applied to a communication system using a routing table other than DHT or a peer-to-peer communication system. An example of a peer-to-peer communication system that does not use DHT is a hybrid peer-to-peer communication system. The present invention may be applied to a hybrid peer-to-peer communication system or a pure peer-to-peer communication system.

1 CPU
2 HDD
3 RAM
4 Decoder unit 5 Video processing unit 6 Display 7 Audio processing unit 8 Speaker 9 Communication unit 21 Program storage area 22 Main operation processing program storage area 23 Routing table generation program storage area 24 First message processing program storage area 25 Second message processing program Storage area 26 Download processing program storage area 27 Address information storage area 28 First routing table storage area 29 Second routing table storage area 30 Version information storage area 31 Content data temporary storage area Tm-n Node device NW Network FW Firewall BR Broadband Router S Content distributed storage system PW First overlay network PL Second overlay network

Claims (9)

An information communication system for transmitting and receiving data through an overlay network composed of a plurality of node devices,
The node device is
A protocol acquisition unit that acquires at least one of IPv4 and IPv6, which are protocols with which the node device can communicate;
A determination unit that determines whether the protocol acquired by the protocol acquisition unit is IPv4 or IPv6;
When the determination unit determines that the protocol acquired by the protocol acquisition unit is IPv4, the first overlay network is configured by at least some of the node devices that can communicate with IPv4, A first table acquisition unit that acquires a first routing table in which location information indicating a location of the node device participating in the first overlay network is registered;
When the determination unit determines that the protocol acquired by the protocol acquisition unit is IPv6, the second overlay network is configured by at least a part of node devices that can communicate with IPv6. A second table acquisition unit for acquiring a second routing table in which the location information of the node devices participating in the second overlay network is registered;
A first transmission for transmitting a message for controlling the information communication system to the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the protocol acquisition unit; And
An information communication system comprising: The information communication system includes:
A first node device that is communicable with IPv4 and receives a participation message transmitted from the node device when participating in the information communication system;
A second node device that is communicable with IPv6 and receives a participation message transmitted from the node device when participating in the information communication system;
With
The first transmission unit of the node device includes a second transmission unit that transmits the participation message to the first node device or the second node device that can communicate with the protocol acquired by the protocol acquisition unit. ,
Based on the participation message transmitted by the second transmission unit, the first table acquisition unit or the second table acquisition unit is at least one of routing tables stored in the first node device or the second node device. The information communication system according to claim 1, wherein a unit is acquired from the first node device or the second node device. A node device of an information communication system for transmitting and receiving data through an overlay network composed of a plurality of node devices,
A protocol acquisition unit that acquires at least one of IPv4 and IPv6, which are protocols with which the node device can communicate;
A determination unit that determines whether the protocol acquired by the protocol acquisition unit is IPv4 or IPv6;
When the determination unit determines that the protocol acquired by the protocol acquisition unit is IPv4, the first overlay network is configured by at least some of the node devices that can communicate with IPv4, A first table acquisition unit that acquires a first routing table in which location information indicating a location of the node device participating in the first overlay network is registered;
When the determination unit determines that the protocol acquired by the protocol acquisition unit is IPv6, the second overlay network is configured by at least a part of node devices that can communicate with IPv6. A second table acquisition unit for acquiring a second routing table in which the location information of the node devices participating in the second overlay network is registered;
A first transmission for transmitting a message for controlling the information communication system to the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the protocol acquisition unit; And
A node device comprising: A storage unit for storing data acquired from any of the plurality of node devices;
A notification message for notifying the plurality of node devices that the node device has stored data in the storage unit, the notification message including the location information of the node device storing data being transmitted to the protocol acquisition unit 4. The first transmission unit transmits to the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the method according to claim 3. The described node equipment. The first transmission unit further transmits a search message for searching for location information indicating a location on the network of one or more content holding node devices that hold desired content from the plurality of node devices,
When the determination unit determines that communication is possible with both IPv4 and IPv6, and the first transmission unit transmits the search message, the first transmission unit is more than the first routing table. 5. The node device according to claim 3, wherein the search message is transmitted with priority on the location information registered in the second routing table. 6. The protocol acquisition unit acquires both IPv4 and IPv6,
The node device is
A receiver for receiving a message for controlling the information communication system;
When the node device that has received the control message by the receiving unit can communicate with both IPv4 and IPv6, the first transmitting unit converts the message received by the receiving unit into the source of the received message 6. The node device according to claim 3, wherein the node device transmits to a protocol different from a protocol with which communication is possible. The receiving unit receives a search message for searching for location information indicating the location on the network of one or more content holding node devices that hold desired content from the plurality of node devices, and the receiving unit When the node device that has received the control message according to the above can communicate with both IPv4 and IPv6, the first transmission unit uses the search message received by the reception unit as the node from which the received message is transmitted. Send to a protocol that the device can communicate with
The node device is
An acquisition unit for acquiring content corresponding to the search message via the different protocol;
A relay unit that relays the content acquired by the acquisition unit to the node device that is the transmission source of the message received by the reception unit;
The node device according to claim 6, further comprising: An information communication method of an information communication system for transmitting and receiving data through an overlay network composed of a plurality of node devices,
A determination step in which the node device determines whether a protocol communicable by the node device is IPv4 or IPv6 based on a protocol acquired by the node device;
When the determination step determines that the protocol acquired by the node device is IPv4, the first overlay network is configured by at least some of the node devices that can communicate with IPv4, A first table acquisition step in which the node device acquires a first routing table in which location information indicating a location of the node device participating in the first overlay network is registered;
When it is determined by the determination step that the protocol acquired by the node device is IPv6, the second overlay network is configured by at least some of the node devices that can communicate with IPv6, A second table acquisition step in which the node device acquires a second routing table in which the location information of the node device participating in the second overlay network is registered;
A first transmission step of transmitting a message for controlling the information communication system to the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the node device; ,
An information communication method including: In the computer of the node device of the information communication system that transmits and receives data through an overlay network composed of a plurality of node devices,
A determination step of determining whether a protocol communicable by the node device is IPv4 or IPv6 based on a protocol acquired by the node device;
When the determination step determines that the protocol acquired by the node device is IPv4, the first overlay network is configured by at least some of the node devices that can communicate with IPv4, A first table acquisition step of acquiring a first routing table in which location information indicating a location of the node device participating in the first overlay network is registered;
When it is determined by the determination step that the protocol acquired by the node device is IPv6, the second overlay network is configured by at least some of the node devices that can communicate with IPv6, A second table acquisition step of acquiring a second routing table in which the location information of the node devices participating in the second overlay network is registered;
A first transmission step of transmitting a message for controlling the information communication system to the node device registered in at least one of the first routing table and the second routing table corresponding to the protocol acquired by the node device; ,
A program characterized by having executed.

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