JP5272991B2 - Information communication system, information communication method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a content to be rarely acquired by a node device from being stored in a support device, and to prevent a content to be frequently acquired by the node device from being deleted from the support device. <P>SOLUTION: In the information communication system, an overlay network is constructed that transmits/receives a content between each node device and each support device connected to each of a plurality of internal networks. The support device acquires a content from another support device or the node device, and stores the acquired content. When the node device acquires a content from an external support device or an external node device, causes an internal support device to acquire the content and acquires the content through the internal support device when the external support device stores the content, and acquires the content without using the internal support device when the external support device does not store the content. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

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.

JP 2006-197400 A

  By the way, there are cases where there are bases in various places such as a company, a school, and a hotel, and a plurality of terminal devices exist in each base. In this case, generally, a private network such as a LAN (Local Area Network) to which each terminal device is connected is formed in the base. The base is provided with a line connected to a public network such as the Internet or a WAN (Wide Area Network).

  In such a case, it is conceivable that each terminal apparatus has a peer-to-peer communication function as disclosed in Patent Document 1. If it does so, each terminal device will be able to acquire a content also from the terminal device which exists in the same base. Therefore, the terminal device may not have to request content from other sites.

  It is also possible to install an edge server dedicated to content storage at each site. In this case, if the terminal device cannot acquire the content from the network in the base, it is conceivable that the terminal device acquires the content from another base via an edge server installed in the same base. At this time, the edge server generally stores content acquired from another base. If it does so, the content requested | required by any one terminal device can be acquired from the edge server installed in the same base.

  However, the memory capacity of the edge server is also limited. Therefore, when the edge server stores the content requested from the terminal device, the old content may have to be deleted. On the other hand, the content requested from the terminal device is not limited to content that is frequently acquired as a whole. In this case, if a request from the terminal device causes a state in which content with a high acquisition frequency is not accumulated in the edge server, the probability of acquiring content from another base via an externally connected line increases. This leads to an increase in traffic on the externally connected line. In addition, the response to the content request is reduced by going through the edge server.

  Therefore, the present invention has been made in view of the above points. The present invention suppresses content that is acquired less frequently by a node device such as a terminal device from being stored in a support device such as an edge server, whereby content that is acquired frequently by a node device is supported by the support device. An object of the present invention is to provide an information communication system, an information communication method, and the like that can be suppressed from being deleted.

In order to solve the above-described problem, the invention according to claim 1 is an information communication system in which a plurality of contents are transmitted and received between a plurality of node devices, and the information communication system includes a plurality of internal networks in an external network. A plurality of node devices connected to the same internal network, and a support device connected to the internal network and supporting content acquisition by the node device for each internal network, the plurality of internal devices An overlay network is constructed that enables transmission and reception of content between a node device connected to each network and the support device, and the support device is connected to the internal network of a connection destination from the node device connected to the network. Content that receives content request information indicating a request for content A request information receiving unit, when the content request information has been received by the content request information receiving unit, and obtain means preparative obtaining content from other the support device that is not connected to the internal network of the destination, storage means for storing the content obtained by the acquisition unit, it has been the content acquired by the acquisition unit, and a content transmission unit for transmitting to said node device that has transmitted the content request information, the node device Is a non-connected support device that is the support device that is not connected to the internal network that is a connection destination, or a non-connection-target node device that is the node device that is not connected to the internal network that is a connection destination. when acquiring, whether the destination outer support device has stored the content And the support device that connects the content request information to the internal network of the connection destination when the determination unit determines that the support device outside the connection destination stores the content. The first content request information transmitting means for transmitting to the connection destination support apparatus, the first content receiving means for receiving the content transmitted from the connection destination support apparatus, and the non-connection destination support apparatus using the determination means Is received, the second content request information transmitting means for transmitting the content request information to the non-connected node device and the content transmitted from the non-connected node device are received. Second content receiving means .

  If the support device acquires and stores content that is frequently acquired by the node device, the content stored in any of the support devices is acquired more frequently than the content that is not stored in any of the support devices. It can be determined that the content is high. Therefore, according to this invention, when the node device acquires the content stored by the support device outside the connection destination via the connection destination support device, the acquired content is stored in the connection destination support device. That is, content with a relatively high acquisition frequency is newly stored in the connection destination support device. On the other hand, if the support device outside the connection destination does not store the content, the node device acquires the content without going through the connection destination support device. That is, content with a relatively low acquisition frequency is not stored in the connection destination support device. As a result, it is possible to prevent the content that is acquired less frequently by the node device from being stored in the support device.

Further , the support device can reliably store the content acquired by the connection destination node device as the content with high acquisition frequency.

The invention according to claim 2 is an information communication system in which a plurality of contents are transmitted / received between a plurality of node devices, wherein the information communication system includes a plurality of internal networks connected to an external network, and the same internal communication system. A plurality of node devices connected to the network, and a support device connected to the internal network and supporting the acquisition of content by the node device for each internal network, and a node device connected to each of the plurality of internal networks; An overlay network that enables transmission / reception of content to / from each of the support devices is constructed, and the information communication system further includes a distribution device that distributes content, and the distribution device is configured for every predetermined period or content Based on the popularity of content at each time, Popularity determination means for determining the degree of content for each content; and transmission means for transmitting content having a relatively high degree of increase in popularity determined by the popularity determination means to at least one of the support devices, The support device includes: a first acquisition unit that acquires content from the other support device or the node device; a first control unit that stores the content acquired by the first acquisition unit in a storage unit; and the distribution device receiving means for receiving the transmitted content, and a second control means for storing the received content in the storage means by the receiving means, said node device are connected to the internal network to connect to The support device outside the connection destination that is not the support device, or the connection device that is not connected to the internal network of the connection destination In the case where content is acquired from a non-connection-destination node device that is a connection-destination device, when the non-connection-destination support device stores content, the connection that is the support device that connects to the internal network of the connection-destination A second acquisition unit configured to acquire the destination support device via the connection destination support device, and obtain the content without the connection destination support device when the non-connection destination support device does not store the content; It is characterized by providing .

  According to the present invention, content that is increasing in popularity is stored in any of the support devices. Content that is gaining popularity is expected to be relatively popular in the future. Therefore, as each node device acquires the content, the content that is expected to be relatively popular is reliably stored in advance in the support device.

According to a third aspect of the invention, in the information communication system according to claim 2, wherein the transmission means, to a predetermined order from the top when the degree of popularity of the rise was ranked content in descending order The content to be entered is a content whose degree of popularity is relatively high.

  According to the present invention, the content whose rank of the degree of increase in popularity falls from the highest rank to the predetermined rank is stored in any of the support devices. Therefore, as each node device acquires content, the content that is expected to be relatively popular is accumulated in the support device in advance.

According to a fourth aspect of the present invention, in the information communication system according to the second or third aspect , the transmission unit is used by the node device or a degree of increase in frequency acquired by the node device. The content having a high degree of frequency increase is set to a content having a high degree of popularity increase.

  According to the present invention, content having a high degree of increase in acquisition frequency or high degree of use is stored in any of the support devices. Therefore, as each node device acquires content, the content that is expected to be relatively popular is accumulated in the support device in advance.

According to a fifth aspect of the present invention, in the information communication system according to any one of the second to fourth aspects, the distribution device has a relatively high degree of increase in popularity determined by the popularity determination unit. Deletion request information transmitting means for transmitting to the support device deletion request information indicating a request to delete content that does not exist, wherein the support device receives the deletion request information transmitted from the distribution device. It further comprises receiving means, and deleting means for deleting the content to be deleted indicated by the deletion request information received by the deletion request information receiving means from the storage means.

  According to the present invention, contents that are not so popular are deleted from the support device. Content that does not increase in popularity is expected to become less popular in the future. Therefore, it is possible to prevent in advance that content that is expected to become relatively less popular with the passage of time is accumulated in the support device.

According to a sixth aspect of the present invention, in the information communication system according to the fifth aspect , the deletion request information transmitting means is predetermined from the top when the contents are ranked in descending order of popularity increase. Content that does not fall within the ranking is content that does not have a relatively high degree of increase in popularity.

  According to the present invention, content that does not fall within the rank of the degree of increase in popularity from the highest rank to a predetermined rank is deleted from the support device. Therefore, it is possible to prevent content that is expected to be relatively less popular with the passage of time from being accumulated in the support device.

A seventh aspect of the present invention is the information communication system according to the fifth or sixth aspect , wherein the deletion request information transmitting means is a degree of an increase in frequency acquired by the node device or the node device. The content that does not increase the frequency of use by the content is set as a content that does not increase the popularity.

  According to the present invention, content whose degree of increase in acquisition frequency or usage frequency is not high is deleted from the support device. Therefore, it is possible to prevent content that is expected to be relatively less popular with the passage of time from being accumulated in the support device.

The invention according to claim 8 is an information communication method in an information communication system in which a plurality of contents are transmitted and received between a plurality of node devices, wherein the information communication system includes a plurality of internal networks connected to an external network, A plurality of node devices connected to the same internal network, and a support device connected to the internal network and supporting the acquisition of content by the node device for each internal network. When acquiring content from a non-connected support device that is the support device that is not connected to the internal network, or from a non-connected node device that is the node device that is not connected to the internal network of the connection destination , Judgment to determine whether the support device outside the connection destination stores the content And when the node device determines that the non-connection-destination support device stores content in the determination step, content request information indicating a content request is sent to the connection-destination internal network. A first content request information transmitting step for transmitting to a connection destination support device, which is the support device to be connected, and content request information indicating a request for content from the node device connected to the internal network of the connection destination of the support device And when the content request information is received by the content request information receiving step, the support device receives from the other support device that is not connected to the internal network of the connection destination. An acquisition step of acquiring content, and the support device A control step of storing the content acquired in the step in a storage unit, a content transmission step in which the support device transmits the content acquired in the acquisition step to the node device that has transmitted the content request information, and A first content receiving step in which the node device receives the content transmitted from the connection destination support device; and the node device is determined by the determination step that the support device outside the connection destination does not store the content. In this case, a second content request information transmitting step for transmitting the content request information to the non-connected node device, and a second content for receiving the content transmitted from the non-connected node device by the node device. And a receiving step .
The invention according to claim 9 is an information communication method in an information communication system in which a plurality of contents are transmitted and received between a plurality of node devices, wherein the information communication system includes a plurality of internal networks connected to an external network, A plurality of node devices connected to the same internal network, and a support device connected to the internal network and supporting content acquisition by the node device are provided for each internal network, and are connected to each of the plurality of internal networks. An overlay network that enables transmission / reception of content between each of the node device and the support device is constructed, and the information communication system further includes a distribution device that distributes the content, and the node device includes a connection destination The support device not connected to the internal network In a case where content is acquired from a certain connection-destination support device or a connection-destination node device that is the node device that is not connected to the connection-destination internal network, the connection-destination support device stores the content. The connection destination support device, which is the support device connected to the internal network of the connection destination, obtains the information via the connection destination support device, and the support device outside the connection destination stores the content. If the content is acquired through the connection destination support device by the node device and the acquisition step of acquiring without the connection destination support device if there is not, the connection destination support device acquires the acquired content The first storage step for storing the information in the storage means, and the distribution device for each predetermined period or each content A popularity determination step for determining the degree of increase in popularity for each content based on the popularity of the content to be determined, and the distribution device has a relatively high increase in popularity determined in the popularity determination step A transmission step of transmitting content to at least one of the support devices, a reception step of receiving the content transmitted from the distribution device by the support device, and the support device received by the reception step And a second storage step for storing the content in the storage means.

The invention according to claim 10 is an information communication system in which a plurality of contents are transmitted and received between a plurality of node devices. The information communication system includes a plurality of internal networks connected to an external network, and the same internal network. A plurality of node devices to be connected; and a support device that is connected to the internal network and supports content acquisition by the node device for each internal network, and the node device connected to each of the plurality of internal networks and the support An overlay network capable of transmitting / receiving content to / from each device is constructed, and the support device receives content request information indicating a content request from the node device connected to the internal network of the connection destination Content request information receiving means to When the content request information is received by the content request information receiving unit, an acquisition unit that acquires content from the other support device that is not connected to the internal network of the connection destination, and the content acquired by the acquisition unit Storage means for storing the content, and content transmission means for transmitting the content acquired by the acquisition means to the node device that has transmitted the content request information. In the case where content is acquired from a support device outside the connection destination that is the support device that is not connected to the network, or the connection destination outside node device that is the node device that is not connected to the internal network of the connection destination , the connection destination Determine whether the external support device stores content A determination step and a connection that is the support device that connects the content request information to the internal network of the connection destination when it is determined by the determination step that the support device outside the connection destination stores content A first content request information transmission step to be transmitted to the destination support device, a first content reception step to receive the content transmitted from the connection destination support device, and the non-connection support device stores the content by the determination step. If it is determined that the content request information has not been received, a second content request information transmission step of transmitting the content request information to the non-connection-destination node device, and a second step of receiving content transmitted from the non-connection-destination node device And a content receiving step .

  According to the present invention, when the node device acquires the content stored by the connection destination support device via the connection destination support device, the acquired content is stored in the connection destination support device. Therefore, content that has a relatively high acquisition frequency can be stored in any support device, and content that has a relatively low acquisition frequency should not be stored in the support device. Is newly stored in the connection destination support apparatus. On the other hand, if the support device outside the connection destination does not store the content, the node device acquires the content without going through the connection destination support device. That is, content with a relatively low acquisition frequency is not stored in the connection destination support device. As a result, it is possible to prevent the content that is acquired less frequently by the node device from being stored in the support device.

It is a figure showing an example of outline composition of contents distribution system S concerning one embodiment. It is a figure which shows the construction example of P2P network PW in the content delivery system S which concerns on one Embodiment. It is a figure which shows an example of the content registered into index information. It is the conceptual diagram which showed an example of a mode that a content is distributed in the content distribution system S which concerns on one Embodiment. It is a figure which shows an example of the content of the information set to content list information. It is a figure which shows the outline | summary structural example of input server ST. It is a figure which shows the example of a schematic structure of edge server SEm. It is a figure which shows the example of a schematic structure of user terminal Tm-n. It is a flowchart which shows the process example of the popular content delivery process in the control part 11 of the input server ST which concerns on one Embodiment. It is a flowchart which shows the process example of the content acquisition process in the control part 41 of user terminal Tm-n which concerns on one Embodiment. It is a figure which shows an example of the content of the information set to content list information. It is a flowchart which shows the process example of the popular content delivery process in the control part 11 of the input server ST which concerns on the modification 2 of one Embodiment.

  Hereinafter, embodiments of the present 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 distribution system.

[1. Overview of content distribution system]
First, a schematic configuration of the content distribution system according to the present embodiment will be described with reference to FIG.

  FIG. 1 is a diagram illustrating a schematic configuration example of a content distribution system S according to the present embodiment.

  As shown in FIG. 1, in the content distribution system S, a distribution center network NS and a plurality of base networks NLm (m = 1, 2, 3,...) Are connected to a network NW. This network NW, distribution center network NS, and each base network NLm are real-world communication networks. The network NW is an example of an external network. The base network NLm is an example of an internal network.

  The network NW is a network for interconnecting the distribution center network NS and each base network NLm. The network NW is, for example, the Internet or a WAN (Wide Area Network). The network NW includes, for example, IX (Internet eXchange), ISP (Internet Service Provider), DSL (Digital Subscriber Line) line provider apparatus, FTTH (Fiber To The Home) line provider apparatus, communication line, etc. Is built by. The network NW may be a network dedicated to the content distribution system S.

  The distribution center network NS is a network constructed in the site of the distribution center. This distribution center network NS is constructed by, for example, a LAN (Local Area Network) or the like.

  The distribution center network NS is connected to server devices such as the input server ST, the management server SM, and the portal server SP, and the management terminal MT. Further, a firewall FW that interconnects the distribution center network NS and the network NW is connected to the distribution center network NS via a communication line LS. The input server ST is an example of a node device.

  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).

  In addition, a plurality of user terminals Tm-n (n = 1, 2, 3...) And an edge server SEm are connected to each base network NLm. Furthermore, a firewall FW or a broadband router BR that interconnects the distribution center network NS and the network NW is connected to each base network via a communication line Lm. Which of the firewall FW and the broadband router BR is installed at the base is arbitrarily determined for each base. The user terminal Tm-n is an example of a node device. The edge server SEm is an example of a support device.

  In the content distribution system S having such a configuration, the functional outline of each device as a component is as follows.

  The input server ST is a server device that inputs content data to a P2P network PW described later. Here, the input of content data refers to placing content data in a state where it can be acquired from the edge server SEm and the user terminal Tm-n. The content data is referred to as “content”. Also, the input server ST distributes popular content to the edge server SEm. Popular content is, for example, content with a relatively large number of downloads within a predetermined unit period, that is, content with a relatively high frequency of download. Popular content is called “popular content”.

  The portal server SP transmits a web page to the user terminal Tm-n in response to a request from the user terminal Tm-n. The Web page transmitted by the portal server SP constitutes a Web site that distributes moving image data as an example of content.

  The management server SM provides a web application for managing the content to be distributed to the management terminal MT. That is, the management server SM transmits a web page for managing content to the management terminal MT.

  The user terminal Tm-n is a terminal device used by a user at the base m. The user terminal Tm-n acquires a Web page from a Web server such as the portal server SP, and displays the acquired Web page on the screen. Further, the user terminal Tm-n acquires and stores content from other user terminals Tm-n, the edge server SEm, or the input server ST. Basically, the user terminal Tm-n can acquire content from the user terminal Tm-n and the edge server SEm installed in any base m. Furthermore, the user terminal Tm-n reproduces content such as moving image data.

  At least one edge server SEm is installed at each base m. The edge server SEm supports content acquisition by the terminal Tm-n connected to the same base m. Specifically, the edge server SEm stores popular content distributed from the input server ST. When the edge server SEm in the same base stores the content, the user terminal Tm-n can acquire the content from the edge server SEm. Basically, the edge server SEm can acquire content from the user terminal Tm-n and the edge server SEm installed at any base m. Further, the edge server SEm stores the acquired content.

[2. Overview of peer-to-peer network]
Next, an overview of a peer-to-peer network in the content distribution system S will be described with reference to FIG.

  FIG. 2 is a diagram illustrating a construction example of the P2P network PW in the content distribution system S according to the present embodiment.

  In the content distribution system S, a peer-to-peer network for content distribution is constructed. This peer-to-peer network is referred to as “P2P network PW”.

  As shown in FIG. 2, the P2P network PW is a logical overlay network built on a network formed by a network NW and a plurality of base networks NLm. The P2P network PW is a network formed by connecting any one of the user terminals Tm-n and the edge server SEm among the user terminals Tm-n and the edge server SEm constituting the content distribution system S. The input server ST may also be connected to the P2P network PW. Each base network NLm is connected to the network NW via the broadband router BR and the firewall FW. Therefore, the port forwarding is set in the broadband router BR and the firewall FW so that the user terminal Tm-n and the edge server SEm can communicate by the peer-to-peer method. 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.

  In the following description, a device connected to the P2P network PW is referred to as a “node”. Devices corresponding to this node are the user terminal Tm-n and the edge server SEm. Alternatively, the user terminal Tm-n, the edge server SEm, and the input server ST correspond to nodes.

  The P2P network PW is realized by a specific algorithm, for example, an algorithm using a DHT (Distributed Hash Table). Each node connected to the content distribution system S is assigned a node ID, which is unique identification information having a predetermined number of digits.

  The node ID is, for example, a value obtained by hashing an IP address, a serial number, or a MAC address (Media Access Control address) individually assigned to each node using a common hash function. The node IDs are arranged in a distributed manner in the ID space. For example, SHA-1 or the like is used as the hash function. The hashed value has a bit length of 160 bits, for example. The node IDs are distributed in the ID space without being distributed. The node ID may be registered for each node by a system administrator, a user, or the like when setting up P2P software for connecting to the P2P network PW. The P2P network PW shown in FIG. 2 shows the ID space of the node ID as a ring. The position of each node shown in the ring-shaped ID space of FIG. 2 corresponds to each node ID.

  Connection to the P2P network PW is performed by a node not connected to the P2P network PW transmitting a participation request message indicating a participation request to the content distribution system to any connected node. Here, participation in the P2P network PW means that a node is connected to the P2P network PW and can acquire content from the P2P network PW. The arbitrary node is, for example, a contact node that is always connected to the P2P network PW. The contact node in the P2P network PW is, for example, the input server ST.

  Each node holds a routing table using DHT. This routing table defines various message transfer destinations on the content distribution system S. Specifically, a plurality of pieces of node information indicating addresses and the like of nodes that are appropriately separated in the ID space are registered in this routing table. This node information includes the node ID, IP address, and port number of the node.

  One node connected to the P2P network PW stores the minimum necessary node information as a routing table. By transferring various messages between the nodes, node information about nodes that do not store node information is acquired.

  Such a routing table using DHT is well known in Japanese Patent Application Laid-Open No. 2006-197400 and the like, and will not be described in detail.

  The P2P network PW stores various content replicas having different contents distributed in a plurality of nodes in a predetermined file format. A replica can be used between the nodes. The original of each content is stored in the input server ST. For example, a content cache area of the edge server SE5 stores a movie content replica with the title XXX. On the other hand, the content cache area of the edge server SE3 stores a replica of the movie content whose title is YYY. In this way, the content is distributed and stored in a plurality of nodes. The content cache area is an area for storing and storing content. For example, the actual content cache area is allocated to a specific hard disk included in the node, or is allocated to a specific partition of the hard disk. The storage capacity of the content cache area of the edge server SEm is larger than the storage capacity of the content cache area of the user terminal Tm-n. As an example, the storage capacity of the content cache area of the edge server SEm is about 10 to 100 times the storage capacity of the content cache area of the user terminal Tm-n. When content cannot be stored in the content cache area, new content is stored. For example, the content is deleted from the content cache area in the oldest order. Whether the content is new or old is determined based on, for example, the use date of the content. Hereinafter, a node in which a 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. This content ID is generated, for example, by hashing the content name + an arbitrary numerical value with a hash function common to the case of obtaining the node ID. Alternatively, the system administrator may give a unique ID value for each content.

  The location of the content that is distributed and stored is stored as index information by a node or the like that manages (stores) the location of the content. Hereinafter, a node that manages (stores) the location of content is referred to as a “root node”. The index information includes a set of node information of the node that stores the content, content ID of the content, and the like. Such a root node is determined to be a node having a node ID closest to the content ID, for example. The node ID closest to the content ID is, for example, the node ID with the highest number of upper digits that match.

  For example, the index information about the content of the movie whose title is XXX is managed by the user terminal T3-1 that is the root node of the content. Further, for example, the index information about the content of the movie whose title is YYY is managed by the user terminal T3-3 that is the root node of the content.

  When a user of a certain node wants to acquire desired content, the node that desires acquisition of the content generates a message. Hereinafter, a node that the user desires to acquire content is referred to as a “user node”. This message is a content location inquiry message including the content ID of the content desired to be acquired, the IP address of the user node, the port number, and the like. The content location inquiry message is a message for searching for a content holding node. The content location inquiry message described above is sent to other nodes according to the DHT routing table acquired by the user node. That is, the user node sends a content location inquiry message toward the root node. As a result, the content location inquiry message finally arrives at the root node by DHT routing using the content ID as a key.

  In each node, attribute information such as content ID of the content is described in the content catalog information. The content attribute information described in the content catalog information includes, for example, a content name, a content ID, a content publication start date and time, a publication end date and time, a valid / invalid flag, and the like. The valid / invalid flag is a flag indicating whether the content is valid or invalid. If this valid / invalid flag indicates invalid, the corresponding content is deleted from the content cache area.

  The content catalog information is distributed from the input server ST to all nodes, for example. The distribution of the content catalog information may be performed by, for example, DHT multicast (multicast message transfer processing) disclosed in Japanese Patent Application Laid-Open No. 2007-053662. Each node may acquire the content catalog information by accessing the input server ST periodically.

  The DHT routing is known in Japanese Patent Application Laid-Open No. 2006-197400 and the like, and thus detailed description thereof is omitted.

  The root node that has received the content location inquiry message obtains index information corresponding to the content ID included therein from the index information cache. The acquired index information is returned to the user node that is the transmission source of the content location inquiry message. The user node that has acquired the index information in this way can download (acquire) the content based on the index information. The user node accesses the content holding node based on the IP address and port number of the content holding node included in the index information. The user node can download the content from the accessed content holding node. The index information may include node information of a plurality of content holding nodes. In this case, the user node selects one content holding node from among the plurality of content holding nodes. The user node can connect to the selected content holding node and download the content.

  Note that the root node transmits a content transmission request message to the content holding node indicated by the IP address and port number included in the index information, whereby the user node transmits the content from the content holding node. Can also be downloaded. In addition, the user node can obtain the index information from a cache node that caches the same index information as the root node until the content location inquiry message reaches the root node.

  When the user node acquires and stores content from the content holding node, the stored user node generates a publish message. This 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 node information of the node device that stores the content. The publish message is sent toward the root node. As a result, the publish message arrives at the root node by DHT routing using the content ID as a key, like the content location inquiry 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. Thus, the user node becomes a new content holding node that holds the content.

[3. Overview of content delivery]
Next, with reference to FIG. 3 to FIG. 5, an outline of the operation of the content distribution system S in the case of distributing content will be described.

[3.1 Priority for content acquisition destination]
As described above, the user terminal Tm-n can acquire content from any user terminal Tm-n and edge server SEm participating in the P2P network PW. However, when content is acquired from the user terminal Tm-n or the edge server SEm connected to the base network NLm other than the base network NLm to which the user terminal Tm-n is connected, the traffic on the communication line Lm increases.

  Therefore, in the content distribution system S, priority is provided to the content acquisition destination. Specific priorities are as follows.

First place: User terminal Tm-n in the same base
2nd: Edge server SEm in the same base
3rd place: Edge server SEm at other sites
4th: User terminal Tm-n at another base
5th place: Input server ST

  The user terminal Tm-n in the same base or the edge server SEm in the same base shown here is the user terminal Tm-n or the edge server SEm connected to the base network NLm to which the user terminal Tm-n that acquires content is connected. It is. Further, the user terminal Tm-n at another base or the edge server SEm at another base is a user terminal Tm-n or edge connected to a base network NLm other than the base network NLm to which the user terminal Tm-n that acquires content is connected. Server SEm. The user terminal Tm-n in the same base is an example of a connection destination node device. The edge server SEm in the same base is an example of a connection destination support device. Further, the edge server SEm at another base is an example of a support device outside the connection destination. In addition, the user terminal Tm-n at another base is an example of a node device outside the connection destination.

  The priority order of the user terminal Tm-n and the edge server SEm in the same base is set higher than the priority order of the user terminal Tm-n and the edge server SEm in another base. The reason is to reduce the traffic of the communication line Lm.

  The priority order of the user terminals Tm-n in the same base is set higher than the priority order of the edge server SEm in the same base. Popular contents are stored in the content cache area of the edge server SEm. That is, content that is highly likely to be downloaded by the user terminal Tm-n is stored in the edge server SEm. Further, the storage capacity of the content cache area of the edge server SEm is larger than the storage capacity of the content cache area of the user terminal Tm-n. For this reason, the edge server SEm is more likely to require content than the user terminal Tm-n. Therefore, in order to reduce the load on the edge server SEm, the priority is set as described above.

  The priority order of the edge server SEm at the other base is set higher than the priority order of the user terminal Tm-n at the other base. Depending on the base m, the base network NLm may be constructed by connecting a plurality of networks via network devices such as router devices. In this case, if a user terminal Tm-n as a content holding node is connected to a network far from the network NW, the content transmitted from the user terminal Tm-n passes through many network devices. . This places a load on these network devices and reduces content acquisition efficiency. Therefore, in order to reduce the load on the network device, the above-described priorities are set. Here, it is assumed that the base network NLm is composed of relay devices such as a plurality of routers. In this case, the edge server SEm or user terminal Tm-n belonging to the base network NLm includes a device that connects to the network NW via a relay device and a device that connects to the network NW without using a relay device. There is. In this case, the load on the relay device can be reduced by connecting the edge server SEm to the network NW without going through the network device. Alternatively, the edge server SEm may be connected to a network relatively close to the network from the network NW among a plurality of devices connected to the base network NLm. To be close to the network means that the number of relay devices to be relayed is small when connecting to the network NW. The network distance from the network NW to a network to which a certain device is connected is the number of networks through which data passes from the network NW to the network to which the device is connected, or the network through which the data passes. The number of devices. The smaller the number of network devices through which data passes, the closer the distance from the network NW.

  The priority of the input server ST is the lowest. The reason is that since the input server ST is a transmission source of all contents, it is necessary to reduce the load on the input server ST as much as possible.

  In order to acquire the content based on the priority order set in this way, when the node storing the content transmits the publish message, the base identification information of the base m where the node itself is installed is transmitted in the publish message. And the node type. The base identification information is identification information of the base m. The node type indicates whether the content holding node is the user terminal Tm-n or the edge server SEm. The root node that has received the publish message stores index information that includes the node information of the content holding node included in the publish message, the content ID of the stored content, the site identification information of the content holding node, the node type, and the like. When the root node receives the content location inquiry message, the root node transmits index information including the base identification information and the node type to the user node. Then, the user node determines a content holding node as a content acquisition destination based on the base identification information and the node type included in the received index information and the priority.

  FIG. 3 is a diagram illustrating an example of contents registered in the index information. Note that the index information shown in FIG. 3 is obtained by integrating the index information of a plurality of contents. Further, in the node information column of FIG. 3, the code of the edge server SEm as the content holding node or the code of the user terminal Tm-n is shown instead of the node information. In the content ID column of FIG. 3, a content name is shown instead of the content ID. In the base identification information column, an office name as an example of the base identification information is shown.

  As shown in FIG. 3, for example, the content whose content name is “Movie 1” is stored in the edge server SE1, the user terminal T1-1, the user terminal T1-2, and the edge server SE3. In this case, the user terminal T1-3 as the user node acquires the content of “movie 1” from the user terminal T1-1 or the user terminal T1-2 having the first priority. When the user node is the user terminal T3-1, the content of “movie 1” is acquired from the edge server SE3 having the second highest priority. When the user node is the user terminal T2-1, the content of “movie 1” is acquired from the edge server SE1 or edge server SE3 having the third highest priority. For example, the content whose content name is “Drama 2” is stored in the user terminal T2-2. In this case, the user terminal T1-1 as a user node acquires the content of “drama 2” from the user terminal T2-2 having the fourth highest priority. The content whose content name is “Movie 3” is not stored in any node. In this case, the user node acquires the content of “movie 3” from the input server ST having the fifth priority.

[3.2 Acquisition of content by user terminal]
FIG. 4 is a conceptual diagram showing an example of how content is distributed in the content distribution system S according to the present embodiment.

  As described above, the user terminal Tm-n uses the user terminal Tm-n in the same site and the edge server SEm in the same site as the content acquisition destination, the user terminal Tm-n in the other site, and the edge of the other site. Select with priority over server SEm. However, if the user terminal Tm-n in the same base or the edge server SEm in the same base does not store the content required by the user terminal Tm-n, the traffic on the communication line Lm does not decrease. Therefore, in the content distribution system S, the popular content is stored in the edge server SEm in which the storage capacity of the content cache area is larger than that of the user terminal Tm-n. The more popular content stored in the edge server SEm, the higher the possibility that the content required by the user terminal Tm-n is stored in the edge server SEm in the same base. Therefore, the user terminal Tm-n can acquire content from the edge server SEm in the same base. Then, when any user terminal Tm-n acquires the content, other user terminals Tm-n in the same site can acquire the content from the user terminal Tm-n acquired first. Therefore, traffic on the communication line Lm can be reduced.

  Specifically, the input server ST periodically distributes popular content to the edge server SEm, and stores the popular content in at least one edge server SEm (FIG. 4 (1)). Also, the input server ST deletes the content that has become unpopular from the edge server SEm. Therefore, the input server ST transmits a deletion command message to the edge server SEm. This deletion command message includes the content ID of the content that has become unpopular. The edge server SEm that has received the delete command message deletes the content that has become unpopular.

  When acquiring content from the edge server SEm at another base or the user terminal Tm-n at another base, the user terminal Tm-n acquires the content by two methods. When the edge server SEm at another base stores the required content, the user terminal Tm-n acquires the content via the edge server SEm in the same base as the first method.

  For example, as shown in FIG. 4, when the content A required by the user terminal T1-2 is stored in the edge server SE5 and the user terminal T4-1, the user terminal T1-2 determines the priority order described above. To acquire the content from the edge server SE5. Specifically, when the user terminal T1-2 receives the index information from the root node of the content A and recognizes that the node storing the content A is a node at another base, the content request message is sent to the edge server SE1. Is transmitted (FIG. 4 (2A)). This content request message includes the content ID of content A. In addition, the content request message includes, for example, the content holding node that is the content request destination, that is, the IP address and port number of the edge server SE5 in this case, as the content request destination information. The content request message is an example of content request information.

  The edge server SE1 that has received the content request message relays the content request message to the edge server SE5 based on the content request destination information included in the content request message (FIG. 4 (3A)). The edge server SE5 that has received the content request message transmits the content A to the edge server SE1 (FIG. 4 (4A)). The edge server SE1 that has received the content A stores the content A (FIG. 4 (5A)). Further, the edge server SE1 transfers the content A to the user terminal T1-2 (FIG. 4 (6A)).

  On the other hand, if the edge server SEm at the other site does not store the required content, but only the user terminal Tm-n at the other site stores, the user terminal Tm-n uses the second method. The content is acquired without going through the edge server SEm in the same base.

  For example, as illustrated in FIG. 4, when the content B required by the user terminal T2-5 is stored only in the user terminal T3-3, the user terminal T2-5 The content request message is transmitted directly (FIG. 4 (2B)). The user terminal T3-3 that has received the content request message transmits the content B directly to the user terminal T2-5 (FIG. 4 (3B)).

  Each popular content is stored in at least one edge server SEm by the distribution by the input server ST. Therefore, content stored in any edge server SEm is considered to be more popular than content not stored in any edge server SEm. Then, when the user terminal Tm-n acquires content stored in the edge server SEm, the content is acquired via the edge server SEm in the same site, so that the acquired content is the edge server SEm in the same site. Also saved. That is, popular content is stored in the edge server SEm. Therefore, as each user terminal Tm-n acquires content, popular content is accumulated in the edge server SEm in the same base. On the other hand, if content that is not popular is accumulated, content that is highly popular has to be deleted in order to secure free space in the content cache area. However, when the user terminal Tm-n acquires content that is not stored in any edge server SEm, the content is acquired without going through the edge server SEm in the same base. Therefore, it is less likely that less popular content is accumulated in the edge server SEm in the same site.

  The edge server SEm receives the content request message addressed to the edge server SEm itself while relaying the content request message transmitted from the user terminal Tm-n in the same site to the edge server SEm in the other site. In some cases, it is necessary to send the requested content. In addition, the edge server SEm relays the content transmitted from the edge server SEm at another site to the user terminal Tm-n in the same site, while receiving the content addressed to the edge server SEm itself. Need to save this content. That is, the edge server SEm needs to determine the destination of the received content request message or content, and change the processing content according to the destination. An example of this determination method will be described below.

  For example, when a user node transmits a content request message, as described above, the IP address and port number of the destination node are included in the content request message as content request destination information.

  The edge server SEm that has received the content request message, when the content request destination information included in the content request message does not match the IP address and port number of the edge server SEm itself, based on the content request destination information. Are relayed to the destination edge server SEm which is a content holding node. At this time, the edge server SEm assigns any unused port number to the received content request message. This port number is different from the port number registered in the routing table as the node information of the edge server SEm itself. The edge server SEm associates the assigned port number with the IP address and port number of the user node and registers them in the relay management table. The IP address and port number of the user node are set as the source address and source port number in the packet header of the received content request message. Then, the edge server SEm relays the content request response message using the assigned port number. That is, the IP address and the assigned port number of the edge server SEm are set in the source address and source port number of the packet header of the relayed content request response message.

  The edge server SEm that has received the content request message whose content request destination information matches the IP address and port number of the edge server SEm itself, the content request response including the requested content to the edge server SEm that has transmitted the content request message. Send a message. In this case, the source address and source port number of the packet header of the received content request message are set in the destination address and destination port number of the packet header of the content request response message.

  The edge server SEm that has received the content request response message stores the content included in the content request response message. Next, the edge server SEm confirms whether or not the port number when the content request response message is received is registered in the relay management table. When this port number is registered in the relay management table, it can be determined that this content request response message is not addressed to the edge server SEm itself. Therefore, the edge server SEm acquires the IP address and port number registered in the relay management table in association with the port number when the content request response message is received. Then, based on the acquired IP address and port number, the edge server SEm relays to the user terminal Tm-n in the same base that is the user node. Then, the edge server SEm deletes the unnecessary port number, the IP address and the port number of the user node from the relay management table.

  On the other hand, when the port number when the content request response message is received is not registered in the relay management table, it can be determined that the content request response message is addressed to the edge server SEm itself. Therefore, the edge server SEm does not relay the content request response message.

[3.3 Determination of contents to be stored in edge server]
The input server ST creates content list information in order to determine the content to be stored in the edge server SEm. The content list information is, for example, information indicating a list of content IDs of published contents and the order of the number of downloads of each content within a predetermined period. That is, the content list information is information indicating the relative popularity of content for each content. The content list information is created every predetermined period.

  FIG. 5 is a diagram illustrating an example of the content of information set in the content list information. FIG. 5 shows an example in which content list information is created every day. For example, assume that the first content list information is created on January 1st. The content list information on January 1 indicates that content A is first, content B is second, and content C is third. The content with the largest number of downloads is the first.

  The maximum number of popular contents stored in the edge server SEm is set in advance. For example, when the maximum number of popular contents is three, the three contents having the ranking of the number of downloads from the first place to the third place become popular contents and are stored in the edge server SEm. That is, according to the ranking on January 1, the contents A, B, and C are stored in the edge server SEm. In the initial stage, the input server ST distributes all the contents A, B, and C to the edge server SEm. For example, an edge server SEm having a relatively low CPU usage rate, an edge server SEm having a relatively large free space in the content cache area, or an edge server SEm having a relatively low frequency of receiving messages from other nodes, The distribution destination edge server SEm may be selected. Information such as the CPU usage rate, the free space in the content cache area, and the message reception frequency is periodically transmitted by the edge server SEm, for example, so that the input server ST can acquire such information. In addition, the number of distribution-destination edge servers SEm may be one or plural. If the popular content is stored in at least one edge server SEm, the popular content is stored in each edge server SEm by the acquisition of the popular content via the edge server SEm by the user terminal Tm-n described above. 5 indicates that the content is a distribution target.

  Next, the ranking has changed on January 2. The first is content A, the second is content G, and the third is content E. Content A continues to be in the top three, but content B and C are out of the top three. Therefore, the input server ST deletes the contents B and C that have become unpopular from the edge server SEm. Therefore, the input server ST transmits a deletion instruction message to the edge server SEm. This deletion instruction message includes the content ID of the content to be deleted, that is, the content IDs of the content B and C in this case. The transmission destination of the deletion instruction message is basically all edge servers SEm. There is a possibility that the contents B and C are stored in the edge server SEm different from the edge server SEm distributed by the input server ST by acquiring the contents via the edge server SEm by the user terminal Tm-n. Because. Note that the transmission destination of the deletion instruction message may be some edge servers SEm. 5 indicates that the content is a deletion target. The edge server SEm that has received the deletion instruction message deletes the content to be deleted from the content cache area when the content B or C of the content to be deleted is stored in the content cache area. The deletion instruction message is an example of deletion request information.

  Thereafter, the edge server SEm distributes the contents E and F that have become popular contents this time to the edge server SEm. Since the content A is already stored in any edge server SEm, it is not necessary to distribute the content A.

  Next, on January 3, the first place is content A, the second place is content H, and the third place is content B. Therefore, the input server deletes the contents E and F, which are no longer popular, from the edge server SEm. Then, the input server ST distributes the contents B and H that have become popular contents this time to the edge server SEm.

  The total number of downloads is calculated based on information transmitted from the user terminal Tm-n to the input server ST. For example, when the user terminal Tm-n acquires the content, the user terminal Tm-n transmits a notification message including the content ID of the acquired content to the input server ST. The input server increases the number of content downloads indicated by the content ID included in the received notification message by one. The input server ST performs ranking based on the number of downloads of each content, for example, at the end of the period, and creates content list information. In addition, the input server ST resets the number of downloads at the end of the period.

[4. Configuration and function of input server ST]
Next, the configuration and function of the input server ST will be described with reference to FIG.

  FIG. 6 is a diagram illustrating a schematic configuration example of the input server ST.

  As shown in FIG. 6, the input server ST includes a control unit 11 as a computer including a CPU having a calculation function, a working RAM, a ROM for storing various data and programs, and the like. In addition, the input server ST includes a storage unit 12 including an HD or the like for storing and storing various data and various programs. Further, the input server ST performs communication control of information with the management server SM and the like through the distribution center network NS, and communication unit 13 for performing communication control of information with the edge server SEm through the network NW and the like. It has. The control unit 11, the storage unit 12, and the communication unit 13 are connected to each other via a bus 14.

  The storage unit 12 stores node IDs, IP addresses, port numbers, and the like of each edge server SEm and each user terminal Tm-n. In addition, setting information is stored in the storage unit 12. This setting information is, for example, information set by a system administrator. For example, the maximum number of popular contents is registered in the setting information. In addition, content list information is stored in the storage unit 12. The storage unit 12 stores content to be distributed. The storage unit 12 stores an operating system, a content distribution control program, an operation management program, a base server management program, and the like. These programs may be downloaded from a predetermined server on the distribution center network NS, for example. Further, these programs may be recorded on a recording medium and read via a drive of the recording medium, for example.

  The control unit 11 functions as a transmission unit and a deletion request information transmission unit in the present invention when the CPU reads and executes a program stored in the storage unit 12 or the like.

[5. Edge server configuration and functions]
Next, the configuration and function of the edge server SEm will be described with reference to FIG.

  FIG. 7 is a diagram illustrating a schematic configuration example of the edge server SEm.

  As shown in FIG. 7, the edge server SEm includes a control unit 21 as a computer including a CPU having a calculation function, a working RAM, a ROM that stores various data and programs, and the like. In addition, the edge server SEm includes a storage unit 22 composed of an HD (hard disk) for storing and storing various data, various programs, and the like, and a buffer memory 23 for temporarily storing received content and the like. . The storage unit 22 is an example of a storage unit. Furthermore, the edge server SEm includes a decoder unit 24 that decodes encoded video data (video information), audio data (audio information), and the like included in the content. Further, the edge server SEm performs a predetermined drawing process on the decoded video data and the like and outputs it as a video signal, and displays a video based on the video signal output from the video processor 25. And a display unit 26 such as a CRT or a liquid crystal display. Further, the edge server SEm converts the decoded audio data into an analog audio signal by D (Digital) / A (Analog) conversion, amplifies it by an amplifier, and outputs it, and this audio processing unit And a speaker 28 that outputs the audio signal output from the sound wave 27 as a sound wave. Furthermore, the edge server SEm controls communication of information with the user terminal Tm-n through the base network NLm, and controls communication of information with other edge servers SEm, input servers ST, etc. through the network NW. The communication part 29 for performing is provided. Furthermore, the edge server SEm includes an input unit (for example, a keyboard, a mouse, a remote controller, an operation panel, or the like) 30 that receives an instruction from a user and gives an instruction signal corresponding to the instruction to the control unit 21. Yes. The control unit 21, the storage unit 22, the buffer memory 23, the decoder unit 24, the communication unit 29, and the input unit 30 are connected to each other via a bus 31. As the edge server SEm, for example, in addition to a dedicated server device, a personal computer or the like can be applied. Note that when the user does not reproduce and use the content on the edge server, the decoder unit 24, the video processing unit 25, the display unit 26, the audio processing unit 27, the speaker 28, and the input unit 30 are unnecessary.

  The storage unit 22 stores a routing table using DHT, index information, content catalog information, a relay management table, and the like. The storage unit 22 stores setting information. In this setting information, for example, information set at the time of setting up P2P software is registered. For example, in the setting information, the IP address and port number of a contact node that is an access destination when participating in the P2P network PW, the IP address and port number of the input server ST, and the like are registered. In the setting information, the base identification information of the base m where the edge server SEm is installed and the node ID assigned to the edge server SEm are registered. A content cache area is allocated to a part of the storage capacity of the storage unit 22. Content is stored in this content cache area. The storage unit 22 stores an operating system, an edge server proxy program, P2P software, and the like. These programs may be downloaded from the input server ST, for example. Further, these programs may be recorded on a recording medium and read via a drive of the recording medium, for example.

  The control unit 21 reads and executes a program stored in the storage unit 22 or the like by the CPU, whereby the first acquisition unit, the content request information receiving unit, the receiving unit, the deletion request information receiving unit, and the deleting unit in the present invention. Function as.

[6. Configuration and functions of user terminal]
Next, the configuration and function of the user terminal Tm-n will be described with reference to FIG.

  FIG. 8 is a diagram illustrating a schematic configuration example of the user terminal Tm-n.

  As shown in FIG. 8, the user terminal Tm-n includes a control unit 41, a storage unit 42, a buffer memory 43, a decoder unit 44, a video processing unit 45, a display unit 46, an audio processing unit 47, a speaker unit 48, and a communication unit. 49, an input unit 50, and a bus 51. The basic configurations and functions of the control unit 41, the storage unit 42, the buffer memory 43, the decoder unit 44, the video processing unit 45, the display unit 46, the audio processing unit 47, the speaker unit 48, the input unit 50, and the bus 51 are as follows. The control unit 21, storage unit 22, buffer memory 23, decoder unit 24, video processing unit 25, display unit 26, audio processing unit 27, speaker unit 28, input unit 30, and bus 31 in the edge server SEm are the same. For example, a personal computer can be applied as the user terminal Tm-n.

  The communication unit 49 controls communication of information with other user terminals Tm-n and the edge server SEm through the base network NLm, and controls communication of information with the portal server SP and the like through the network NW.

  The storage unit 42 stores a routing table using DHT, index information, content catalog information, and the like. The storage unit 42 stores setting information. In this setting information, for example, information set at the time of setting up P2P software is registered. For example, in the setting information, the IP address and port number of a contact node that is an access destination when participating in the P2P network PW, the IP address and port number of the input server ST, and the like are registered. In the setting information, the base identification information of the base m where the user terminal Tm-n is installed, and the node ID assigned to the user terminal Tm-n are registered. In addition, a content cache area is allocated to a part of the storage capacity of the storage unit 42. Content is stored in this content cache area. The storage unit 42 stores an operating system, a user content acquisition program, P2P software, a Web browser program, a player program, and the like. Note that these programs may be downloaded from, for example, the edge server SEm or the portal server SP. Further, these programs may be recorded on a recording medium and read via a drive of the recording medium, for example.

  The control unit 41 reads out and executes a program (including the node program of the present invention) stored in the storage unit 42 or the like by the CPU, whereby the second acquisition unit, the first content request information transmission unit, the first It functions as one content receiving means, second content request information transmitting means, and second content receiving means.

[8. Operation of content distribution system]
Next, the operation of the content distribution system S according to the present embodiment will be described with reference to FIGS.

  FIG. 9 is a flowchart illustrating a processing example of popular content distribution processing in the control unit 11 of the input server ST according to the present embodiment.

  The popular content distribution process shown in FIG. 9 is started periodically, for example. First, the control part 11 acquires the maximum number of popular contents from the setting file memorize | stored in the memory | storage part 12 (step S1). Next, the control unit 11 counts the number of downloads of content during a predetermined period for each content from the log information collected from the user terminal Tm-n (step S2). Next, the control unit 11 creates content list information indicating the content in descending order of the number of downloads based on the total number of downloads (step S3).

  Next, the control unit 11 compares the previously created content list information with the currently created content list information (step S4). Then, the control unit 11 determines whether or not there is a content that is different between the previous time and the current time in the content that is in the top of the number of downloads (step S5). The content in the top of the number of downloads is the content in the rank from the first rank to the rank corresponding to the maximum number of popular contents acquired from the setting file. At this time, if there is a content that is different between the previous time and the current content among the content in the top of the number of downloads (step S5: YES), the control unit 11 uses the previous download number as the deletion request information transmission means. Among the contents that are higher in the list, a delete instruction message for contents not included in the upper rank is transmitted to the edge server SEm (step S6). The control unit 21 may omit the transmission of the content deletion instruction message.

  When the content deletion instruction message is stored in the content cache area, the control unit 21 of the edge server SEm that has received the content deletion instruction message as the deletion request information receiving unit stores the content as a content cache area as the deletion unit. Delete from.

  When the control unit 11 of the input server ST finishes the process of step S6, as the transmission means, the content not included in the previous high rank among the content included in the high download count this time is at least one edge server. Transmit to SEm (step S7).

  The control unit 21 of the edge server SEm that has received the content as the reception unit stores the content in the content cache area.

  The control unit 11 of the input server ST determines that there is no different content between the previous time and the current time in the content that has been downloaded at the top in step S5 (step S5: NO), or the processing in step S7 is completed. If it is, the popular content distribution process is terminated.

  FIG. 10 is a flowchart illustrating a processing example of content acquisition processing in the control unit 41 of the user terminal Tm-n according to the present embodiment.

  The process of FIG. 10 is started when the user terminal Tm-n receives a content inquiry response message from the root node after transmitting a content location inquiry message as a user node. First, the control unit 41 acquires the base identification information of the base m where the user terminal Tm-n itself is installed and the node type of the user terminal Tm-n itself from the setting information stored in the storage unit 42. (Step S21).

  Next, the control unit 41 determines whether or not the combination of the site identification information and the node type that matches the combination of the site identification information and the node type acquired from the setting file is set in the index information included in the content inquiry response message. Is determined (step S22). That is, the control unit 41 determines whether any user terminal Tm-n in the same base stores the content. At this time, when the combination of the site identification information and the node type that matches the combination of the site identification information and the node type acquired from the setting file is set (step S22: YES), the control unit 41 proceeds to step S23. Transition. In step S23, the control unit 41 acquires content from an arbitrary user terminal Tm-n among the user terminals Tm-n in the same site where the node information is included in the index information.

  On the other hand, when the combination of the site identification information and the node type that matches the combination of the site identification information and the node type acquired from the setting file is not set (step S22: NO), the control unit 41 proceeds to step S24. To do. In step S24, the control unit 41 includes, in the index information included in the content inquiry response message, a combination of the base identification information that matches the base identification information acquired from the setting file and the node type indicating the edge server. Determine whether it is set. That is, the control unit 41 determines whether or not the edge server SEm in the same base stores the content. At this time, the control unit 41 sets a combination of the base identification information that matches the base identification information acquired from the setting file and the node type indicating the edge server (step S24: YES). The process proceeds to step S25. In step S25, the control unit 41 acquires content from the edge server SEm in the same site where the node information exists in the index information.

  On the other hand, when the site identification information that matches the site identification information acquired from the setting file is not set (step S24: NO), the control unit 41 selects any of the necessary contents as the second acquisition unit. It is determined whether or not the edge server SEm is stored and acquired from the content holding node via the edge server SEm in the same site, or directly from the content holding node without going through the edge server SEm in the same site. get.

  Specifically, the control unit 41 determines whether or not a node type indicating an edge server is set in the index information included in the content inquiry response message (step S26). That is, the control unit 41 determines whether or not the edge server SEm at another base stores the content. At this time, if the node type indicating the edge server is set (step S26: YES), the control unit 41 is the same from the edge server SEm of the other base where the node information exists in the index information. Content is acquired through the edge server SEm in the site (step S27). Specifically, the control unit 41 transmits, as first content request information transmission means, a content request message addressed to the edge server SEm at another site to the edge server SEm within the same site. The control unit 21 of the edge server SEm edge server SEm in the same base that has received the content request message as the content request information receiving means acquires content from the edge server SEm at another base that is a content holding node as the first acquisition means. . And the control part 21 preserve | saves the acquired content in a content cache area. Further, the control unit 21 relays the acquired content to the user terminal Tm-n that is the transmission source of the content request message as a content transmission unit. The control unit 41 of the user terminal Tm-n receives the content relayed from the edge server SEm in the same site as the first content receiving unit.

  On the other hand, when the node type indicating the edge server is not set (step S26: NO), the control unit 41 determines whether the node type indicating the user terminal is set. (Step S28). That is, the control unit 41 determines whether or not the user terminal Tm-n at another base stores the content. At this time, when the node type indicating the user terminal is set (step S28: YES), the control unit 41 starts from the user terminal Tm-n at the other base where the node information exists in the index information. The content is acquired without going through the edge server SEm in the same base (step S23). Specifically, the control unit 41 transmits a content request message as a second content request information transmission unit to the user terminal Tm-n at another site which is a content holding node. And the control part 41 receives the content transmitted from the user terminal Tm-n of another base as a 2nd content receiving means.

  On the other hand, when the node type indicating the user terminal is not set (step S28: NO), the control unit 41 acquires the content from the input server ST without going through the edge server SEm in the same base. (Step S29).

  When the processing of step S23, S25, S27, or S29 is completed, the control unit 41 stores the acquired content in the content cache area (step S30). Next, the control unit 41 transmits a publish message to the root node (step S31). This publish message includes the node information of the user terminal Tm-n, the content ID of the stored content, the base identification information acquired from the setting file, and the node type. When this process is completed, the control unit 41 ends the content acquisition process.

  As described above, according to the present embodiment, when the user terminal Tm-n acquires content from the edge server SEm at another base or the user terminal Tm-n at another base, the content distribution system S is as follows. To work. First, when the required content is stored in the edge server SEm at another base, the user terminal Tm-n acquires the content via the edge server SEm at the same base. When the content is acquired by the user terminal Tm-n via the edge server SEm at the same site, the edge server SEm stores the content. On the other hand, when the required content is not stored in the edge server SEm at another base, the user terminal Tm-n acquires the content without passing through the edge server SEm at the same base.

  Therefore, when the user terminal Tm-n acquires the popular content stored by the edge server SEm at the other site through the edge server SEm at the same site, the popular content is newly added to the edge at the same site. Stored in the server SEm. The less popular content stored only at the user terminal Tm-n at another base is acquired by the user terminal Tm-n without going through the edge server SEm at the same base. That is, less popular content is not stored in the edge server SEm at the same location. Thereby, it is possible to suppress content that may be less popular from being stored in the edge server SEm.

  Further, when the user terminal Tm-n stores the necessary content in the edge server SEm at another base, it transmits a content request message to the edge server SEm in the same base. The edge server SEm that has received the content request message from the user terminal Tm-n in the same base acquires the content from the edge server SEm at another base as a content holding node. Then, the edge server SEm stores the acquired content. Further, the edge server SEm transmits the acquired content to the user terminal Tm-n in the same site as the transmission source of the content request message.

  Therefore, the edge server SEm can reliably store the popular content acquired by the user terminal Tm-n in the same base.

  In addition, the input server ST transmits popular content to at least one of the edge servers SEm. Then, the edge server SEm that has received the content from the input server ST stores the received content.

  Accordingly, the popular content is stored in any edge server SEm. Therefore, as each user terminal Tm-n acquires content, popular content is reliably stored in the edge server SEm.

  In addition, the input server ST transmits to the edge server SEm a delete instruction message for content that is no longer popular content. Then, the edge server SEm that has received the content deletion instruction message from the input server ST deletes the content that is no longer a popular content from the content cache area.

Therefore, content that was once popular but has now become less popular is deleted from the edge server SEm. Therefore, it is possible to prevent content that has become less popular over time from being accumulated in the edge server SEm.
[9. Modified example]
[9.1 Modification 1]
In the embodiment described above, the input server ST transmits content having a large number of downloads in a predetermined period to the edge server SEm as highly popular content. However, the input server ST may distribute content that has a high degree of popularity instead of distributing content that is already popular.

  Specifically, the input server ST creates a content list information indicating a list of content IDs of published contents as content list information and indicating an increase in the number of downloads of each content. Therefore, the input server ST totals the number of downloads of each content every predetermined period. Then, the number of download increases is calculated from the difference in the number of downloads for each period. The download increase number is a number obtained by subtracting the number of downloads in the previous period from the number of downloads in a certain period. This increase may be positive or negative. Note that content with a large increase in popularity is referred to as “popular content”.

  FIG. 11 is a diagram illustrating an example of the content of information set in the content list information. FIG. 11 shows an example in which content list information is created every day. For example, assume that the first content list information is created on January 1st. The content list information of January 1 indicates that the first number of download increases is content A, the second is content B, and the third is content C. The content with the largest number of download increases is the first.

  When the maximum number of popular contents is 3, the contents A, B, and C become rapidly increasing contents and are stored in the edge server SEm. Therefore, in the initial stage, the input server ST distributes the contents A, B, and C to the edge server SEm.

  Next, the ranking has changed on January 2. The first is content A, the second is content B, and the third is content D. Content A and B are still in the top three, but content C is out of the top three. Therefore, the input server ST deletes from the edge server SEm the content C that has a smaller download increase than the content in the top three.

  After that, the edge server SEm distributes the content D having the latest increase in downloads within the top three to the edge server SEm.

  Next, on January 3, the first place is the content G, the second place is the content F, and the third place is the content D. Therefore, the input server deletes the contents A and C from the edge server SEm that are smaller than ST and the contents with the highest number of downloads within the top three.

  The contents of the popular content distribution process in the control unit 11 of the input server ST are basically the same as the contents of the process shown in FIG. 9 in the first embodiment. However, in this embodiment, the control unit 11 aggregates the number of download increases for each content from the number of downloads in a predetermined period at the time of the previous aggregation and the number of downloads in the predetermined period at the time of the current aggregation as the popularity determination unit (Step S11). S2). The control unit 11 creates content list information indicating the content in descending order of download increase (step S3). And the control part 11 transmits the deletion instruction | indication message of the content which is not in the high rank among the contents which are higher in the previous download increase number to the edge server SEm as deletion request information transmission means (step S6). ). Further, the control unit 11 transmits, as a transmission means, content that is not included in the top rank of the number of download increases this time to at least one edge server SEm (step S7).

  As described above, according to the present modification, the edge server SEm calculates the number of download increases for each content based on the number of content downloads at the time of the previous aggregation and the number of content downloads at the time of the current aggregation. In addition, the edge server SEm transmits to the at least one edge server SEm the content that is in the higher rank in which the calculated increase in downloads is determined by the maximum number of popular contents. Then, the edge server SEm that has received the content from the input server ST stores the received content.

  Accordingly, the rapidly increasing content that is popular is stored in one of the edge servers SEm. This rapidly increasing content is expected to become a popular content in the future. Therefore, as each user terminal Tm-n acquires content, the content that is expected to increase in popularity is reliably stored in the edge server SEm in advance.

  In addition, the input server ST transmits, to the edge server SEm, a deletion instruction message for content that is no longer a rapidly increasing content. Then, the edge server SEm that has received the content deletion instruction message from the input server ST deletes the content that is no longer a rapidly increasing content from the content cache area.

  Therefore, although the way of increasing popularity has been large in the past, at the present time, the way of increasing popularity is slowed down or the content that has become less popular is deleted from the edge server SEm. Content that has become less popular or has become less popular is expected to be no longer popular. Therefore, it is possible to prevent in advance that content that is expected to be no longer popular content over time is accumulated in the edge server SEm.

In the present embodiment, the degree of increase in popularity is determined based on the number of download increases, but the criterion for determining the degree of increase in popularity is not limited to this. For example, a download increase rate may be used. This download increase rate can be obtained by dividing the number of downloads within a predetermined period when this time is totaled by the number of downloads within a predetermined period when the previous time was totaled.
[9.2 Modification 2]
In the embodiment described above, the input server ST deletes the content that has become unpopular from the edge server SEm when distributing the popular content. However, if there is a sufficient free space in the content cache area of the edge server SEm, it is not always necessary to delete it.

  Specifically, when the input server ST selects the edge server SEm to which the popular content is distributed, the input server ST deletes the content whose publication period has expired from the selected edge server SEm. This is because content that has passed the public period is not used. Whether or not the publication period has expired can be determined by comparing the publication end date and time described in the content catalog with the current date and time.

  Next, if there is a free space in the content cache area of the distribution destination edge server SEm that can store the popular content to be distributed, the content is not deleted. In this case, it is not necessary to delete the already stored popular contents in order to store the popular contents to be distributed by the edge server SEm as the distribution destination.

  On the other hand, if the content cache area of the distribution destination edge server SEm does not have enough capacity to store the distribution-target popular content, the input server ST can quickly distribute the content that has become unpopular in the distribution destination. It is deleted from the edge server SEm to secure a free space for storing popular contents. The content that suddenly lost popularity is content that has a high download reduction rate or content that has a large number of download reductions. The download reduction rate can be obtained by dividing the number of downloads within a predetermined period when the previous aggregation is performed by the number of downloads within the predetermined period when the aggregation is performed this time. Further, the number of download reductions can be obtained by subtracting the number of downloads within a predetermined period at the time of the current aggregation from the number of downloads within the predetermined period at the time of the previous aggregation.

  FIG. 12 is a flowchart illustrating a processing example of popular content distribution processing in the control unit 11 of the input server ST according to the second modification of the present embodiment. FIG. 12 shows an example in which the content to be deleted is determined from the download reduction rate.

  First, the control unit 11 acquires the maximum number of popular contents from the setting file stored in the storage unit 12 (step S61). Next, the control unit 11 aggregates the number of content downloads during a predetermined period for each content from the log information collected from the user terminal Tm-n. Further, the control unit 11 aggregates the download reduction rate for each content from the number of downloads at the previous aggregation and the number of downloads at the current aggregation (Step S62). Next, the control unit 11 creates content list information indicating the contents in descending order of the number of downloads and indicating the contents in descending order of the download reduction rate based on the counting result (step S63).

  Next, the control unit 11 compares the previously created content list information with the currently created content list information (step S64). Then, the control unit 11 determines whether there is a content that is different between the previous time and the current time among the content that is in the higher number of downloads (step S65). At this time, the control unit 11 selects the distribution-destination edge server SEm when there is a content that is different between the previous time and the current content among the content in the higher number of download increases (step S65: YES). From the selected edge server SEm, information on a list of stored contents is acquired (step S66). Specifically, the control unit 11 transmits a stored content list request message to the distribution destination edge server SEm. And the control part 11 receives the information of the preservation | save content list information transmitted from edge server SEm of a delivery destination. In this stored content list information, a list of content IDs of content stored in the edge server SEm is described.

  Next, the control unit 11 transmits, to the distribution-destination edge server SEm, a deletion instruction message for contents whose expiration date has expired among the contents stored in the distribution-destination edge server SEm (step S67).

  Next, the control unit 11 calculates the free capacity of the content cache area of the distribution destination edge server SEm (step S68). If the total capacity of the content cache area of each edge server SEm is stored in the storage unit 12 in advance, the total capacity of the content cache area of the distribution destination edge server SEm can be acquired from the storage unit 12. Since all the contents are basically stored in the storage unit 12, the data size of each content can be grasped by referring to the file management information in the storage unit 12. Alternatively, the data size of each content may be described in the content catalog. In any case, the control unit 11 can calculate the total data size of the content in which the content ID is described in the acquired stored content list information. The total data size does not include the data size of the content whose publication period has expired. Then, the control unit 11 subtracts the total capacity of the content cache area of the distribution destination edge server SEm from the total capacity of the content cache area of the distribution destination edge server SEm, thereby reducing the free capacity of the content cache area. calculate.

  Next, the control unit 11 calculates the total data size of the content not included in the previous previous rank as the total data size of the content to be distributed among the content included in the higher number of downloads this time (step S69). .

  Next, the control unit 11 determines whether or not the free space in the content cache area is equal to or larger than the total data size of the content to be distributed (step S70). At this time, when the free capacity of the content cache area is less than the free capacity of the content cache area (step S70: NO), the control unit 11 makes the free capacity of the content cache area equal to or larger than the free capacity of the content cache area. In this way, a content deletion instruction message with a high download reduction rate is transmitted to the distribution-destination edge server SEm (step S71). Specifically, the control unit 11 selects the content with the highest download reduction rate as the content to be deleted in order from the highest download reduction rate. The control unit 11 repeats this selection until the free space in the content cache area becomes equal to or greater than the total data size of the content to be distributed. Then, the control unit 11 transmits a deletion instruction message including the content ID of each selected deletion target content to the distribution destination edge server SEm.

  When the free space in the content cache area is greater than or equal to the free space in the content cache area in step S70 (step S70: YES), or when the processing in step S71 is completed, the control unit 11 Data is transmitted to the distribution-destination edge server SEm (step S72). And the control part 11 when the content which is different in the last and this time in the content which is in the upper rank of download number in step S65 does not exist (step S65: NO), or when the process of step S72 is completed. In this case, the popular content distribution process is terminated.

  As described above, according to this modification, when the input server ST runs out of free space in the content cache area of the distribution-destination edge server SEm, the content having a high download reduction rate or the number of download reductions A content deletion instruction message with a large amount of content is transmitted to the edge server SEm of the distribution destination. As a result, content whose popularity has suddenly dropped is deleted from the distribution-destination edge server SEm.

  Therefore, the usage efficiency of the content cache area of the edge server SEm can be increased. Moreover, although it is not popular, content that is likely to be added to popular content in the future can be left in the edge server SEm.

  In the above embodiment, the priority of the edge server SEm at the other base is set higher than the priority of the user terminal Tm-n at the other base as the content acquisition destination. good. In this case, in the content acquisition process illustrated in FIG. 10, when the user terminal Tm-n stores the necessary content in both the edge server SEm at the other base and the user terminal Tm-n at the other base. The content may be acquired from the edge server SEm at another base, or the content may be acquired from the user terminal Tm-n at another base. However, in this case, the user terminal Tm-n acquires content via the edge server SEm at the same site.

  In the above embodiment, the popularity of content is determined based on the number of downloads of content in a predetermined period, that is, the frequency of download. However, the criterion for determining popularity is limited to this. It is not a thing. For example, the popularity of the content may be determined based on the number of contents used by the user terminal Tm-n during a predetermined period, that is, the frequency of use. The number of contents used includes, for example, the number of times content is reproduced. In this case, for example, when the user terminal Tm-n reproduces the content, the notification message including the content ID of the reproduced content is transmitted to the input server ST. Then, the input server ST counts the number of reproductions.

  Moreover, in the said embodiment, although the peer to peer network using DHT was applied to the overlay network, it is not restricted to this. For example, a system using another peer-to-peer network or an overlay network may be applied. As a peer-to-peer network that does not use DHT, for example, there is a hybrid peer-to-peer network.

11 Control unit 12 Storage unit 13 Communication unit 14 Bus 21, 41 Control unit 22, 42 Storage unit 23, 43 Buffer memory 24, 44 Decoder unit 25, 45 Video processing unit 26, 46 Display unit 27, 47 Audio processing unit 28, 48 Speaker 29, 49 Communication unit 30, 50 Input unit 31, 51 Bus ST Input server SEm Edge server Tm-n User terminal SM Management server SP Portal server MT Management terminal FW Firewall BR Broadband router Lm, LS Communication line NLm Base network NW network NS distribution center network PW P2P network S content distribution system

Claims (10)

An information communication system in which a plurality of contents are transmitted and received between a plurality of node devices,
The information communication system includes:
Multiple internal networks are connected to the external network,
A plurality of node devices connected to the same internal network;
A support device connected to the internal network and supporting content acquisition by the node device;
For each internal network,
An overlay network is constructed that enables transmission and reception of content between each of the node device connected to each of the plurality of internal networks and the support device,
The support device includes:
Content request information receiving means for receiving content request information indicating a request for content from the node device connected to the internal network of the connection destination;
And acquisition means for acquiring the content from the when the content request information has been received, the support device connection destination other not connected to the internal network by the content request information receiving means,
Storage means for storing the content obtained by the acquisition means,
Content transmitting means for transmitting the content acquired by the acquiring means to the node device that has transmitted the content request information;
With
The node device is
Content is acquired from a non-connection support device that is the support device that is not connected to the internal network of the connection destination, or from a non-connection-target node device that is the node device that is not connected to the internal network of the connection destination Determining means for determining whether or not the non-connection-destination support device stores content;
When it is determined by the determination means that the support device outside the connection destination stores the content, the content request information is sent to the connection destination support device that is the support device connected to the internal network of the connection destination. First content request information transmitting means for transmitting;
First content receiving means for receiving content transmitted from the connection destination support device;
A second content request information transmitting unit configured to transmit the content request information to the non-connection-destination node device when the determination unit determines that the non-connection-destination support device does not store content;
Second content receiving means for receiving content transmitted from the non-connected node device;
An information communication system comprising: An information communication system in which a plurality of contents are transmitted and received between a plurality of node devices,
The information communication system includes:
Multiple internal networks are connected to the external network,
A plurality of node devices connected to the same internal network;
A support device connected to the internal network and supporting content acquisition by the node device;
For each internal network,
An overlay network is constructed that enables transmission and reception of content between each of the node device connected to each of the plurality of internal networks and the support device,
The information communication system further comprises a distribution device for distributing content,
The distribution device includes:
Popularity determination means for determining the degree of increase in popularity for each content based on the popularity of the content for each predetermined period or for each content;
Transmission means for transmitting content having a relatively high degree of increase in popularity determined by the popularity determination means to at least one of the support devices;
The support device includes:
First acquisition means for acquiring content from the other support device or the node device;
First control means for storing in the storage means the content acquired by the first acquisition means;
Receiving means for receiving content transmitted from the distribution device;
Second control means for storing the content received by the receiving means in the storage means;
With
The node device is
Content is acquired from a non-connection support device that is the support device that is not connected to the internal network of the connection destination, or from a non-connection-target node device that is the node device that is not connected to the internal network of the connection destination In this case, if the support device outside the connection destination stores the content, the connection destination support device that is the support device connected to the internal network of the connection destination is acquired and the connection destination support device passes through the connection destination support device. An information communication system comprising: a second acquisition unit that acquires and acquires the content without the connection destination support device when the non-connection destination support device does not store the content. The information communication system according to claim 2,
In the transmission unit, when the contents are ranked in descending order of popularity, the content that falls within a predetermined rank from the top is set as content having a relatively high degree of popularity. An information communication system. In the information communication system according to claim 2 or claim 3,
The transmission means sets a content having a high degree of increase in popularity as a content having a high degree of increase in frequency acquired by the node device or a high degree of increase in frequency used by the node device. An information communication system. The information communication system according to any one of claims 2 to 4,
The distribution device includes:
A deletion request information transmitting means for transmitting to the support device deletion request information indicating a request to delete content whose degree of increase in popularity determined by the popularity determination means is not relatively high;
The support device includes:
Delete request information receiving means for receiving the delete request information transmitted from the distribution device;
A deletion unit that deletes the content to be deleted indicated by the deletion request information received by the deletion request information receiving unit from the storage unit;
An information communication system, further comprising: The information communication system according to claim 5, wherein
The deletion request information transmitting means has a relatively high degree of increase in popularity for content that does not fall within a predetermined rank from the top when content is ranked in descending order of popularity increase. An information communication system characterized by being content. In the information communication system according to claim 5 or 6,
The deletion request information transmitting means may increase the popularity of content that does not have a high degree of increase in the frequency acquired by the node device or a high frequency of use by the node device. An information communication system characterized by having no content. An information communication method in an information communication system in which a plurality of contents are transmitted and received between a plurality of node devices,
The information communication system includes:
Multiple internal networks are connected to the external network,
A plurality of node devices connected to the same internal network;
A support device connected to the internal network and supporting content acquisition by the node device;
For each internal network,
The node device is a support device outside the connection destination that is not connected to the internal network of the connection destination, or the node device outside the connection destination that is the node device that is not connected to the internal network of the connection destination A determination step of determining whether or not the connection-destination support device stores the content;
When the node device determines that the non-connection-destination support device stores content in the determination step, the node device connects content request information indicating a content request to the connection-destination internal network. A first content request information transmission step for transmitting to a connection destination support device which is a support device;
A content request information receiving step in which the support device receives content request information indicating a content request from the node device connected to the internal network of the connection destination;
When the support device receives the content request information in the content request information receiving step, an acquisition step of acquiring content from another support device that is not connected to the internal network of the connection destination;
A control step in which the support device stores the content acquired in the acquisition step in a storage unit;
A content transmission step in which the support device transmits the content acquired in the acquisition step to the node device that has transmitted the content request information;
A first content receiving step in which the node device receives content transmitted from the connection destination support device;
Second content request information for transmitting the content request information to the non-connected node device when the node device determines that the non-connected support device does not store content in the determining step Sending process;
A second content receiving step in which the node device receives content transmitted from the non-connected node device;
An information communication method characterized by comprising: An information communication method in an information communication system in which a plurality of contents are transmitted and received between a plurality of node devices,
The information communication system includes:
Multiple internal networks are connected to the external network,
A plurality of node devices connected to the same internal network;
A support device connected to the internal network and supporting content acquisition by the node device;
For each internal network,
An overlay network is constructed that enables transmission and reception of content between each of the node device connected to each of the plurality of internal networks and the support device,
The information communication system further comprises a distribution device for distributing content,
The node device is a support device outside the connection destination that is not connected to the internal network of the connection destination, or the node device outside the connection destination that is the node device that is not connected to the internal network of the connection destination In the case of acquiring content from the connection destination, if the support device outside the connection destination stores the content, the connection destination support device that is the support device connected to the internal network of the connection destination is caused to acquire the connection destination. Obtaining via a support device, and when the support device outside the connection destination does not store the content, an acquisition step of obtaining without the connection destination support device;
A first storage step in which when the content is acquired by the node device via the connection destination support device, the connection destination support device stores the acquired content in a storage unit;
A popularity determination step in which the distribution device determines the degree of increase in popularity for each content based on the popularity of the content for each predetermined period or content.
A transmission step in which the distribution device transmits content having a relatively high degree of increase in popularity determined in the popularity determination step to at least one of the support devices;
A receiving step in which the support device receives content transmitted from the distribution device;
A second storage step in which the support device stores the content received in the reception step in the storage means;
An information communication method characterized by comprising: In an information communication system in which a plurality of contents are transmitted and received between a plurality of node devices,
The information communication system includes:
Multiple internal networks are connected to the external network,
A plurality of node devices connected to the same internal network;
A support device connected to the internal network and supporting content acquisition by the node device;
For each internal network,
An overlay network is constructed that enables transmission and reception of content between each of the node device connected to each of the plurality of internal networks and the support device,
The support device includes:
Content request information receiving means for receiving content request information indicating a request for content from the node device connected to the internal network of the connection destination;
An acquisition unit that acquires content from the other support device that is not connected to the internal network of the connection destination when the content request information is received by the content request information reception unit;
Storage means for storing the content acquired by the acquisition means;
Content transmitting means for transmitting the content acquired by the acquiring means to the node device that has transmitted the content request information;
With
In the computer of the node device,
Content is acquired from a non-connection support device that is the support device that is not connected to the internal network of the connection destination, or from a non-connection-target node device that is the node device that is not connected to the internal network of the connection destination A determination step of determining whether or not the non-connection-destination support device stores content;
If it is determined in the determination step that the support device outside the connection destination stores content, the content request information is sent to the connection destination support device that is the support device connected to the internal network of the connection destination. A first content request information transmitting step for transmitting;
A first content receiving step of receiving content transmitted from the connection destination support device;
A second content request information transmission step of transmitting the content request information to the non-connection-destination node device when the determination step determines that the non-connection-destination support device does not store content;
A second content receiving step of receiving content transmitted from the non-connected node device;
  A program characterized by having executed.

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