JP2012078901A - Server device, page transmission program and page transmission method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a server device which enables a terminal device to efficiently acquire contents distributed over an overlay network without being participated in the overlay network, a page transmission program and a page transmission method.SOLUTION: A server device determines location information to be described on a Web page on the basis of a retrieval result of contents requested from a first terminal device, the location information indicating locations of information processing apparatuses constituting an overlay network. Then, the server device transmits the Web page on which the determined location information is described to the first terminal device.

Description

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

  In recent years, a peer-to-peer distribution system has been known. In a peer-to-peer distribution system, a plurality of content data are distributed and stored in a plurality of node devices in an overlay network composed of a plurality of node devices. Each node device participating in the overlay network can acquire content data from other node devices in the overlay network. Hereinafter, the content data is referred to as “content”.

  In recent years, a system has been proposed that uses such a peer-to-peer distribution system to distribute content that can be distributed from a Web server through an overlay network. In this system, a terminal device including a Web browser participates in the overlay network as a node device. In addition, a unique content ID assigned to the content is described in the web page provided from the web server to the terminal device. For example, as disclosed in Patent Literature 1, the terminal device can search and acquire the location of the content from the overlay network using the content ID described in the Web page.

JP 2007-34630 A

  By the way, in the system described above, in order for the terminal device to acquire content distributed on the overlay network, it is necessary to participate in the overlay network. Therefore, it is necessary to install a predetermined peer-to-peer application program in the terminal device.

  However, some users who use the terminal device do not want to install a peer-to-peer application program on the terminal device and participate in the overlay network.

  The present invention has been made in view of the above points and the like, and a server device and a page transmission capable of efficiently acquiring content distributed on the overlay network without the terminal device participating in the overlay network. It is an object to provide a program and a page transmission method.

  In order to solve the above-described problem, the invention according to claim 1 is configured such that an overlay network is configured by a plurality of information processing apparatuses that can communicate with each other via a network, and content is stored in one or more of the information processing apparatuses. A server device capable of communicating with the information processing device in a distribution system, wherein a receiving unit receives a request for a predetermined content from a first terminal device that does not participate in the overlay network, and is received by the receiving unit. Search means for searching for the location of the information processing apparatus storing the content corresponding to the request in the overlay network, and location information described on a Web page based on a search result by the search means, Determining means for determining the location information indicating the location of the information processing device; A generating unit that generates a Web page in which the location information determined by the determination unit is described; and a transmitting unit that transmits the Web page generated by the generating unit to the first terminal device. It is characterized by.

  According to a second aspect of the present invention, in the server device according to the first aspect, when a plurality of the location information is searched by the search means, the first information is selected from the plurality of the location information. The location information satisfying a condition to be introduced to the terminal device is determined as location information described in the Web page.

  The invention according to claim 3 is the server device according to claim 2, wherein the server device acquires first area information indicating an area where the first terminal device is installed; Second acquisition means for acquiring second area information indicating an area where the information processing apparatus is installed, and the determination means includes the first area information acquired by the first acquisition means and the second acquisition Based on the second area information acquired by the means, the location information of the information processing apparatus installed in an area close to the area where the first terminal apparatus is installed is used as the first terminal apparatus. It is characterized in that it is preferentially determined as the location information that satisfies the conditions to be introduced.

  According to a fourth aspect of the present invention, in the server device according to the second or third aspect, the server device includes an ISP (Internet Service Provider) used for the first terminal device to connect to the network. A third acquisition unit that acquires first ISP information to be displayed; and a fourth acquisition unit that acquires second ISP information indicating an ISP used for the information processing apparatus to connect to the network. The information processing apparatus using the same ISP as the first terminal apparatus based on the first ISP information acquired by the third acquisition means and the second ISP information acquired by the fourth acquisition means. The location information is preferentially determined as the location information that satisfies a condition to be introduced to the first terminal device.

  According to a fifth aspect of the present invention, in the server device according to any one of the second to fourth aspects, the information processing device includes a second terminal device different from the first terminal device. The information processing device is connected via communication means, and the information processing device acquires content to be transmitted to the second terminal device from another information processing device via the overlay network, or the content is sent to the second information processing device. Control means for controlling the operation to be transmitted to the terminal device, wherein the server device obtains operation information indicating whether or not the operation controlled by the control means of the information processing device is being executed. An obtaining unit, and the determining unit obtains the location information of the information processing apparatus in which the operation is not being executed based on the operation information obtained by the fifth obtaining unit. Characterized in that it preferentially determined as satisfying the location information presented to.

  According to a sixth aspect of the present invention, in the server device according to any one of the second to fifth aspects, the server device sets a date or time when the information processing device accesses another information processing device. 6th acquisition means which acquires the access information which shows, The said determination means, based on the access information acquired by the 6th acquisition means, the location information of the information processing apparatus with the old date or time, The location information satisfying the condition to be introduced to the first terminal device is preferentially determined as the location information.

  The invention according to claim 7 manages the location information indicating the location of the information processing device participating in the overlay network in the server device according to any one of claims 1 to 6. Seventh acquisition means for acquiring the location information from a management device, and first determination means for determining whether or not the number of the location information searched by the search means is equal to or less than a predetermined number, When the first determination unit determines that the number of the location information searched by the search unit is equal to or less than a predetermined number, the determination unit determines the location information acquired by the seventh acquisition unit. The location information of an information processing apparatus that does not store the content corresponding to the request is determined as location information described in the Web page.

  According to an eighth aspect of the present invention, in the server device according to any one of the first to sixth aspects, the location information indicating a location of the information processing device participating in the overlay network is managed. A date or time at which the information processing device corresponding to the location information searched by the search means provides the content to another information processing device; Or an eighth acquisition unit that acquires provision information indicating the date or time when the location information was provided to the other information processing apparatus, and the date or time indicated in the provision information acquired by the eighth acquisition unit The second determination means for determining whether or not the number of the information processing devices included in a predetermined period is equal to or greater than a predetermined number, and the second determination means to the eighth acquisition means. If it is determined that the number of the information processing devices whose date or time indicated in the provided information acquired within a predetermined period is greater than or equal to the predetermined number, the determining means The location information of an information processing apparatus that does not store the content corresponding to the request is determined as location information to be described on the Web page, from among the predetermined number of acquired location information. .

  The invention according to claim 9 is a distribution system in which an overlay network is configured by a plurality of information processing devices that can communicate with each other via a network, and content is stored in one or more of the information processing devices. Receiving a request for a predetermined content from a first terminal device not participating in the overlay network in a computer included in a communicable server device; and storing the content corresponding to the received request Searching the location of the information processing apparatus on the overlay network, and determining the location information indicating the location of the information processing apparatus, which is location information described in a Web page, based on the search result Step and the determined location information are described. Generating a Web page, the Web page that the generated, a page transmission program for executing the steps of: transmitting to the first terminal device.

  The invention according to claim 10 is a Web page transmission method in a distribution system in which an overlay network is configured by a plurality of information processing devices capable of communicating with each other via a network, and content is stored in one or more of the information processing devices. A server device receiving a request for a predetermined content from a first terminal device not participating in the overlay network, and the server device receiving the content corresponding to the received request. Searching the location of the information processing apparatus to be stored in the overlay network, and the server apparatus is location information described on a Web page based on the search result, and indicates the location of the information processing apparatus Determining the location information; and the server device, Generating a Web page in which the determined location information is described, and the server device transmitting the generated Web page to the first terminal device. To do.

  According to the invention described in claim 1, 9 or 10, the server device is the location information described in the Web page based on the search result of the content requested from the first terminal device, and the overlay network The location information indicating the location of the information processing apparatus to be configured is determined. Then, the server device transmits a Web page in which the determined location information is described to the first terminal device. Therefore, the first terminal device can efficiently acquire the content distributed on the overlay network by using the location information described in the Web page transmitted from the server device without participating in the overlay network. . According to the second aspect of the present invention, even when location information corresponding to a plurality of information processing devices is searched by the search means, the location information is introduced to the first terminal device. Location information that satisfies the conditions can be provided to the terminal device via the Web page.

  According to the third aspect of the present invention, the location information of the information processing apparatus installed in the area close to the area where the first terminal apparatus that requested the content is installed is preferentially transmitted via the Web page. Can be provided to the first terminal device. Therefore, the first terminal device can quickly acquire content from the introduced information processing device.

  According to the fourth aspect of the present invention, location information of an information processing device that uses the same ISP as the first terminal device that has requested the content is preferentially provided to the first terminal device via the Web page. be able to. Therefore, the first terminal device can quickly acquire content from the introduced information processing device. Moreover, the usage fee by straddling between different ISPs can be reduced.

  According to the fifth aspect of the present invention, location information of an information processing device that is not executing an operation for providing content to the second terminal device is preferentially provided to the first terminal device via the Web page. can do. Therefore, it is possible to avoid the execution of the above operation by the information processing apparatus being hindered.

  According to the sixth aspect of the present invention, location information of an information processing device with an old date when content is provided to another information processing device can be preferentially provided to the first terminal device via the Web page. . Therefore, it is possible to avoid the concentration of access to a specific information processing apparatus.

  According to the seventh aspect of the present invention, when there are few information processing devices that store the content requested by the first terminal device on the overlay network, the number of information processing devices that store the content on the overlay network is increased. be able to.

  According to the eighth aspect of the present invention, when there are few information processing devices that store the content requested by the first terminal device on the overlay network, the number of information processing devices that store the content on the overlay network is increased. be able to.

It is a figure showing an example of outline composition of a contents distribution system concerning this embodiment. (A) is a block diagram showing a schematic configuration example of a Web server WS. (B) is a block diagram showing a schematic configuration example of the management server MS. (C) is a block diagram illustrating a schematic configuration example of the router Rm. It is a sequence diagram which shows the process etc. of each apparatus until a content is provided to the user terminal UT which made the request for content. (A) is a flowchart showing an example of IP address determination processing. (B) is a flowchart showing an example of processing using regional information and ISP information. (A)-(C) is a figure which shows an example of the search result by the search process of the content X. FIG. (D) is a figure which shows an example of the registration information of several nodes Nn other than the content holding node shown by a search result. (E) is a diagram showing a description example of HTML constituting the Web page acquired in step S3.

  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. Content distribution system configuration and operation overview ]
First, with reference to FIG. 1, the structure and operation | movement outline | summary of the content delivery system which concerns on this embodiment are demonstrated. FIG. 1 is a diagram illustrating a schematic configuration example of a content distribution system according to the present embodiment. As shown in FIG. 1, the content distribution system S according to the present embodiment is configured by a Web server WS, a management server MS, a user terminal UT, a router Rm (m = 1, 2, 3... J), and the like. ing. Web server WS, management server MS, user terminal UT, and router Rm are connected to network NW. The network NW is composed of the Internet or the like. The web server WS is a server for configuring a content distribution site. The Web server WS is an example of a server device in the present invention. The management server MS is a server that manages information on node devices Nn participating in an overlay network ON described later. The management server MS is an example of a management device in the present invention. The user terminal UT is an example of a first terminal device in the present invention. The user terminal UT is, for example, a personal computer or a portable device used by the user. A web browser program is installed in the user terminal UT. Note that the router Rm, the user terminal UT, and the like can be connected to the network NW using an IP address assigned by an ISP (Internet Service Provider) server (not shown).

  In addition, as shown in FIG. 1, in the content distribution system S, a base network NLm is constructed for each of a plurality of bases Pm. Examples of the base include a karaoke store, a school, a company, a house, and other facilities. The base network NLm is a private network such as a LAN (Local Area Network). Also, a router Rm and a plurality of base terminals Tm-l (l = 1, 2, 3) are connected to each base network NLm. The router Rm is a relay device that relays IP (Internet Protocol) packets between the network NW and the base network NLm. The router Rm also functions as an edge server that distributes content to the base terminal Tm-l. The base terminal Tm-l is an example of a second terminal device in the present invention. The base terminal Tm-l can reproduce the content distributed from the router Rm. Note that the viewing terminal Tm-l at each site Pm is not limited to communicating with only the router Rm connected to the same site network NLm. For example, the viewing terminal T1-1 at the site P1 can communicate not only with the router R1 connected to the same site network NL1, but also with the router R2, the web server WS, and the like at other sites P2.

  As shown in FIG. 1, in the content distribution system S, the overlay network ON is activated by the participation of a plurality of node devices Nn (n = 1, 2, 3,... K) that can communicate with each other via the network NW. It is configured. The node device is an example of an information processing device in the present invention. The node device is hereinafter referred to as “node”. The overlay network ON is a logical network that forms a virtual link. The overlay network ON is realized by a specific algorithm, for example, an algorithm using a distributed hash table. The distributed hash table is hereinafter referred to as “DHT (Distributed Hash Table)”. Here, participating in the overlay network ON means operating in a state where various messages can be transmitted / received to / from other nodes Nn via the overlay network ON based on a routing table using DHT. Note that a routing table using DHT is known in Japanese Patent Application Laid-Open No. 2006-197400 and the like, and thus detailed description thereof is omitted.

  In this embodiment, the router Rm and the Web server WS participate in the overlay network ON as the node Nn. Therefore, a peer-to-peer program for executing control processing as the node Nn is installed in the router Rm and the Web server WS. Here, the peer-to-peer application program is hereinafter referred to as “P2P program”. Further, the router Rm regularly participates in the overlay network ON as a resident node. Here, “steady participation” means that, for example, when the resident node is not at the time of failure or maintenance, it participates without leaving the overlay network ON. In addition to the router Rm at each site Pm, for example, a P2P program for executing control processing as the node Nn may be installed in a device that is always connected to the network NW at each home. If the P2P program is installed in the user terminal UT, the user terminal UT can participate in the overlay network ON as the node Nn. In this case, the user terminal UT is a general node that does not always participate regularly in the overlay network ON. For example, the user terminal UT participates in the overlay network ON for a predetermined time such as when the user uses the user terminal UT.

  A node ID is assigned to each node Nn participating in the overlay network ON. This node ID is unique identification information for identifying the node Nn from among the nodes Nn participating in the overlay network ON. In addition, various contents with different contents are distributed and stored in the plurality of nodes Nn participating in the overlay network ON. A content ID is assigned to the content stored in the node Nn. The content ID is unique identification information for identifying the content from among a plurality of contents stored in the node Nn when the overlay network is ON. Note that the node ID and the content ID are generated by, for example, a hash function common to the overlay network ON.

  Here, the node Nn that stores the content is hereinafter referred to as a “content holding node”. The location of the content is stored as index information in the node Nn that manages the location of the content. The node Nn that manages the location of the content is hereinafter referred to as a “root node”. The index information includes a set of the node information of the content holding node storing the content and the content ID of the content. The node information includes, for example, the IP address, port number, and node ID of the content holding node. Here, the IP address of the content holding node is an example of location information indicating the location of the content holding node. Note that the root node is determined to be, for example, the node Nn to which the node ID closest to the content ID is assigned. The node ID closest to the content ID is, for example, the node ID with the highest number of upper digits that match.

  A certain node Nn may acquire predetermined content from the content holding node via the overlay network ON. In this case, the node Nn performs a process of searching for the location of the content holding node that stores predetermined content in the overlay network ON. This processing is hereinafter referred to as “content search processing”. Here, the predetermined content is, for example, content selected as an acquisition target by the node Nn. The node Nn that performs content search processing is hereinafter referred to as a “user node”. The content search process is performed based on the content ID of the content. Specifically, the user node generates a content location inquiry message in the content search process. The content location inquiry message is a message for inquiring the location of the content to the root node. The content location inquiry message includes the IP address and port number of the user node that transmits this message, and the content ID of the content. Then, the user node transmits the generated content location inquiry message to the root node by DHT routing. The DHT routing is known in, for example, Japanese Patent Application Laid-Open No. 2007-053662, and detailed description thereof is omitted. The root node that has received the content location inquiry message acquires index information corresponding to the content ID included in the content location inquiry message. Then, the root node returns the acquired index information to the user node. The index information returned in this way includes the IP address of one or more content holding nodes that store the content. Thus, the user node receives the index information from the root node. With this index information, the user node can find the content to be acquired. Then, the user node accesses the content holding node based on the IP address of the content holding node included in the received index information. Then, the user node requests content from the content holding node and acquires this content from the content holding node.

  By the way, as described above, if the P2P program is installed in the user terminal UT, the user terminal UT can participate in the overlay network ON as the node Nn. In this case, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-034630, the user terminal UT can acquire content using a content ID described in a Web page provided from a predetermined Web site. However, some users who use the user terminal UT do not want to install the P2P program in the user terminal UT and participate in the overlay network ON. This is because, for example, there is resistance to installation due to the trouble of installing the P2P program, anxiety that the behavior of the P2P program itself cannot be seen, and the like. Therefore, a method for acquiring content distributed in the overlay network ON without the user terminal UT participating in the overlay network ON will be described below.

  As an example of this method, a method using DNS (Domain Name System) can be considered. In this method, a URL (Uniform Resource Locator) of content distributed by overlay network ON is described in a Web page provided from a predetermined Web site to the user terminal UT. Also, in the DNS server (not shown), correspondence information in which the domain name included in the content URL is associated with the IP address of the content holding node that stores the content is registered. This correspondence information is updated every predetermined time. Then, when the Web browser of the user terminal UT receives the Web page from the Web site, it inquires of the DNS server about the IP address corresponding to the domain name included in the URL described in the Web page. As a result, the Web browser of the user terminal UT acquires the IP address of the content holding node that stores the content when the overlay network is ON. That is, the domain name is converted into an IP address. Then, the Web browser of the user terminal UT can access the content holding node corresponding to the acquired IP address and acquire the content. However, in the method using DNS, it is assumed that there are inquiries from many user terminals UT to the DNS server all at once in a short time. In this case, there is a problem that access is concentrated from a plurality of user terminals UT to the content holding node introduced from the DNS server, and responses are delayed.

  Therefore, the method described below is configured such that the user terminal UT introduces the node Nn from which the user terminal UT obtains content from the Web server WS to the user terminal UT without obtaining an IP address from the DNS server. In this method, the IP address of the node Nn is described in the Web page provided from the Web server WS to the user terminal UT. Therefore, when the Web server WS receives a request for predetermined content from the user terminal UT, the Web server WS performs content search processing corresponding to the request. Then, the Web server WS determines the IP address of the node Nn described in the Web page based on the search result by the content search process.

[ 2. Configuration and function of Web server WS ]
Next, the configuration and functions of the Web server WS will be described with reference to FIG. FIG. 2A is a block diagram illustrating a schematic configuration example of the Web server WS. As shown in FIG. 2A, the Web server WS includes a control unit 11, a storage unit 12, a communication unit 13, and the like. The control unit 11, the storage unit 12, and the communication unit 13 are connected to each other via a bus 14. The Web server WS may be composed of a plurality of servers such as an application server and a database server.

  The storage unit 12 is composed of, for example, a hard disk drive. The storage unit 12 stores an operating system, an HTTP (HyperText Transfer Protocol) server program, a P2P program, and the like. The HTTP server program and the P2P program are examples of the page transmission program of the present invention. The HTTP server program, the P2P program, and the like may be downloaded from a predetermined server connected to the network NW, for example. Alternatively, for example, the HTTP server program and the P2P program may be recorded on a recording medium and read via a drive of the recording medium.

  The storage unit 12 stores a web page. The Web page is composed of a structured document file described in HTML (Hyper Text Markup Language), XML (Extensible Markup Language), or the like. Further, the storage unit 12 stores a routing table using DHT used in overlay network ON. Note that the routing table using DHT is generated by participating in the overlay network ON. The communication unit 13 performs communication control with the management server MS, the user terminal UT, the router Rm, and the like through the network NW.

  The control unit 11 includes a CPU having a calculation function, a working RAM, a ROM, and the like. The control unit 11 is an example of a reception unit, a search unit, a determination unit, a generation unit, a transmission unit, first and second determination units, and first to eighth acquisition units in the present invention. The control unit 11 has a clock function and a timer function. The control unit 11 operates as the HTTP server unit 11a by the execution of the HTTP server program stored in the storage unit 12 or the like by the CPU. By this HTTP server unit 11a, the Web server WS functions as an HTTP server. In addition, the control unit 11 operates as the node processing unit 11b when the CPU executes the P2P program stored in the storage unit 12 or the like. With this node processing unit 11b, the Web server WS also functions as the node Nn. The processing of the HTTP server unit 11a and the node processing unit 11b is executed by a single CPU by multitasking or multicore. Or you may comprise so that the process of the HTTP server part 11a and the node process part 11b may be performed by each CPU with two CPUs.

[ 3. Configuration and function of management server MS ]
Next, the configuration and function of the management server MS will be described with reference to FIG. FIG. 2B is a block diagram illustrating a schematic configuration example of the management server MS. As shown in FIG. 2B, the management server MS includes a control unit 21, a storage unit 22, a communication unit 23, and the like. The control unit 21, the storage unit 22, and the communication unit 23 are connected to each other via a bus 24. The management server MS may be composed of a plurality of servers such as an application server and a database server.

  The storage unit 22 is composed of, for example, a hard disk drive. The storage unit 22 stores an operating system, a server program, and the like. In addition, a management database is constructed in the storage unit 22. In the management database, node information, area information, ISP information, operation information, content holding number information, and the like are registered for each node Nn. The information registered in the management database is hereinafter referred to as “registration information”. The node Nn whose registration information is registered in this management database is, for example, a resident node. However, registration information of the node Nn other than the resident node may be registered in the management database.

  Here, the area information indicates an area where the node Nn is installed. In other words, the region indicates the position of the real world. The regional information is represented by, for example, a continent name, a country name, a prefecture name, a municipality name, or an area name or a point name arbitrarily determined by the system operator. The regional information is determined by the node Nn or the management server MS based on, for example, the longitude / latitude, address, or postal code of the node Nn. Note that the longitude / latitude, address, or postal code is input and stored in the node Nn, for example, by the user at the time of installation of the node Nn. Alternatively, the regional information is determined based on the IP address assigned to the node Nn, for example, when the node Nn or the management server MS uses DNS. In this case, the area information can be determined from alphanumeric characters included in the domain name converted from the IP address by DNS. In addition, for example, when the information indicating the region is not included in the alphanumeric characters included in the domain name, the region information may not be determined from the IP address assigned to the node Nn. In this case, the area information may be determined from an IP address assigned to a router close to the node Nn. The router close to the node Nn is, for example, a router that is relayed first when a packet is transmitted from the node Nn to another node Nn. The IP address of the router close to the node Nn can be acquired by the node Nn executing a known traceroute. Further, the area information may be determined based on a response speed from the node Nn when the node N1 accesses another node Nn, for example. In this case, the regional information of the other node Nn whose response speed is equal to or higher than the predetermined speed becomes the regional information of the node N1.

  The ISP information indicates the ISP used for the node Nn to connect to the network NW. The ISP information is determined based on the IP address assigned to the node Nn, for example, by using the DNS by the node Nn or the management server MS, similarly to the area information. Alternatively, the ISP information is input and stored in the node Nn, for example, by the user at the timing when the node Nn is installed.

  The node information, the regional information, and the ISP information of the node Nn are transmitted from the node Nn and registered in the management database when the node Nn participates in the overlay network ON, for example. Alternatively, the node Nn may be a node Nn installed by the system operator. In this case, the node information, the area information, and the ISP information of the node Nn are registered in the management database from the system operator's terminal, for example.

  The operation information indicates whether or not an operation for providing content to the base terminal Tm-l connected to the same base network NLm as the router Rm is being executed when the node Nn is the router Rm. Indicates. The operation for providing content to the base terminal Tm-l is hereinafter referred to as “base operation”. The base operation includes an operation of acquiring content transmitted from the node Nn to the base terminal Tm-l from the content holding node via the overlay network ON. This base operation may include the above-described content search processing. Further, the base operation includes an operation in which the node Nn transmits content to the base terminal Tm-l via the base network NLm. The operation information includes information such as load information and bandwidth information of the node Nn. The load information indicates a CPU load factor, a memory load factor (%), and the like of the node Nn. The band information indicates a band (bps) that can be allocated for the node Nn to transmit content in response to a content request from the user terminal UT or the like. In other words, the assignable bandwidth is an effective bandwidth of a communication line connected to the communication unit of the node Nn. The effective bandwidth can be calculated by the node Nn accessing a speed measurement server (not shown) or a predetermined node Nn and measuring the data communication speed. Further, the effective bandwidth may be calculated by counting the number of sessions with the communication partner with which communication is performed. The content holding number information indicates the number of contents stored in the node Nn. Further, the operation information and the content holding number information of the node Nn are transmitted from the node Nn and registered in the management database, for example, when the node Nn participates in the overlay network ON and thereafter at a predetermined time interval. The registration information already registered in the management database is updated with the operation information and content holding number information transmitted from the node Nn at predetermined time intervals. Here, the predetermined time interval is, for example, an interval of several seconds.

  When the node Nn withdraws from the overlay network ON, information indicating withdrawal is transmitted from the node Nn to the management server MS. As a result, the node information and the like of the withdrawn node Nn are deleted from the management database. Alternatively, information indicating withdrawal may be registered in the management database in association with the node information of the node Nn that has withdrawn.

  The communication unit 23 performs communication control with the Web server WS, the user terminal UT, the router Rm, or the like through the network NW.

  The control unit 21 includes a CPU having a calculation function, a working RAM, a ROM, and the like. The control unit 21 has a clock function and a timer function. Then, the control unit 21 performs a process of collecting operation information, load information, bandwidth information, content holding number information, and the like from the node Nn by executing a server program stored in the storage unit 22 or the like by the CPU. In addition, the control unit 21 performs processing for registering the collected information in the management database. Furthermore, the control unit 21 performs a process of transmitting registration information registered in the management database to the Web server WS. Note that the registration information registered in the management database is transmitted to the Web server WS, for example, periodically or when a request is received from the Web server WS.

[ 4. Configuration and function of router Rm ]
Next, the configuration and function of the router Rm will be described with reference to FIG. FIG. 2C is a block diagram illustrating a schematic configuration example of the router Rm. As illustrated in FIG. 2C, the router Rm includes a control unit 31, a buffer memory 32, a storage unit 33, a communication unit 34a, a communication unit 34b, and the like. The control unit 31, the buffer memory 32, the storage unit 33, the communication unit 34a, and the communication unit 34b are connected to each other via a bus 35.

  The buffer memory 32 temporarily accumulates content received via the communication unit 34a.

  The storage unit 33 is composed of, for example, a hard disk drive. The storage unit 33 stores an operating system, an IP packet relay processing program, an HTTP server program, a P2P program, and the like. In addition, the storage unit 33 stores a routing table using DHT used for overlay network ON. Note that the routing table using DHT is generated by participating in the overlay network ON. In addition, the content is stored in the content storage area provided in the storage unit 33. In some cases, the content is composed of a plurality of files. In this case, for example, each file is distributed and stored in a plurality of nodes Nn participating in the overlay network ON as one content. For this reason, the storage unit 33 of one node Nn may store one file among a plurality of files constituting the content. For example, it is assumed that the content includes a first moving image file, a second moving image file, and a control file. In this case, the first moving image file is stored in the storage unit 33 of the node N1, for example. Further, the second moving image file is stored in the storage unit 33 of the node N2, for example. Further, the control file is stored in the storage unit 33 of the node N3, for example. A unique content ID is assigned to each file distributed and stored as content.

  The communication unit 34a performs communication control with another router Rm, the Web server WS, the management server MS, the user terminal UT, or the like through the network NW. The communication unit 34b performs communication control with the viewing terminal Tm-l through the base network NLm.

The control unit 31 includes a CPU having a calculation function, a working RAM, a ROM, and the like. The control unit 31 is an example of a control unit that controls the above-described base operation. Further, the control unit 31 operates as the IP packet relay processing unit 31a by the execution of the IP packet relay processing program stored in the storage unit 33 or the like by the CPU. The IP packet relay processing unit 31a performs processing for relaying IP packets from other routers or hosts in the network layer, which is the third layer of the OSI (Open Systems Interconnection) reference model. Since the function of the IP packet relay processing unit 31a is the same as that of a known router or L3 switching hub, detailed description thereof is omitted. Further, the control unit 31 operates as the HTTP server unit 31b by the execution of the HTTP server program stored in the storage unit 33 or the like by the CPU. With this HTTP server unit 31b, the router Rm functions as an HTTP server. Further, the control unit 31 operates as the node processing unit 31c by the execution of the P2P program stored in the storage unit 33 or the like by the CPU. By this node processing unit 31c, the router Rm also functions as a node Nn. The processing of the IP packet relay processing unit 31a, the HTTP server unit 31b, and the node processing unit 31c is executed by a single CPU by multitasking or multicore. Alternatively, the processes of the IP packet relay processing unit 31a, the HTTP server unit 31b, and the node processing unit 31c may be configured to be executed by two or more CPUs.
[ 5. Operation of Content Distribution System S ]
Next, the operation of the content distribution system S according to the present embodiment will be described with reference to FIG. FIG. 3 is a sequence diagram illustrating processing of each device until content is provided to the user terminal UT that has requested the content. In the operation described below, it is assumed that the HTTP server program and the P2P program are activated on the Web server WS. Further, when the P2P program of the Web server WS is activated, the Web server WS participates in the overlay network ON as the node Nn. Further, it is assumed that the HTTP server program and the P2P program are activated in the router Rm. Further, when the P2P program of the Web server WS is activated, the router Rm participates in the overlay network ON as the node Nn.

  In FIG. 3, the Web browser of the user terminal UT accesses the Web server WS using the HTTP protocol. Then, the web browser of the user terminal UT transmits, for example, a request for the content X designated by the user to the web server WS (step S1). This request is, for example, an HTTP request indicating a request for a web page for viewing content.

  On the other hand, when receiving the request from the user terminal UT, the HTTP server unit 11a of the Web server WS acquires a Web page in which the URL of the content X corresponding to the request is described from the storage unit 12 (Step S2). Next, the HTTP server unit 11a extracts the URL of the content X included in the acquired web page (step S3). Next, the HTTP server unit 11a inquires of the node processing unit 11b about the acquisition destination of the content X (step S4). Specifically, the HTTP server unit 11a stores an inquiry command in a predetermined storage area of a RAM accessible by the node processing unit 11b. The URL extracted in step S4 is added to this inquiry command.

  Next, upon receiving an inquiry from the HTTP server unit 11a, the node processing unit 11b of the Web server WS performs a content X search process (step S5). This content X search process is a search process of content X corresponding to the received request. In the content X search process, the node processing unit 11b acquires a content ID corresponding to the URL added to the inquiry command. The content ID can be acquired from, for example, an association table in which the URL of the content X distributed by overlay network ON and the content ID are associated with each other. In this case, the association table is stored in the storage unit 12 in advance. Alternatively, the content ID may be acquired by hashing the URL of the content X with a hash function common to the overlay network ON. Then, the node processing unit 11b transmits a content location inquiry message including the acquired content ID to the root node by DHT routing. As a result, the node processing unit 11b acquires index information as a search result from the root node of the content X as described above. That is, the node processing unit 11b finds the content holding node that stores the content X corresponding to the request from the overlay network ON by the content X search processing.

  In the present embodiment, the index information includes the last provided date information corresponding to the node information of the searched content holding node. The final provision date information is an example of provision information and access information in the present invention. This final provision date information indicates the latest date when the content holding node provided the content X to the user terminal UT. Here, provision of the content X includes (1) the content holding node uploads the content X to the user terminal UT, and (2) the user terminal UT downloads the content X from the content holding node. . Alternatively, the final provision date information may indicate the latest date when the index information including the node information of the content holding node of the content X is provided from the root node to the user terminal UT. Alternatively, the last provided date information may indicate the latest date when the content holding node is accessed from the user terminal UT. In the present embodiment, the date and time are included in the final provision date, but only the time may be used. For example, when the content holding node uploads the content X to the user terminal UT, an upload message is transmitted to the root node of the content X. The upload message is a message indicating that the content X has been uploaded to the user terminal UT. This upload message includes node information of the content holding node and date information indicating the date when the content X was uploaded. As a result, the root node that has received the upload message stores the date information included in this message as the last provided date information in association with the node information of the content holding node that is the transmission source of this message. In addition, the last provision date information of the same content holding node may already be stored. In this case, the last provided date information is updated with the date information included in the upload message. The date indicated in the date information may be a date when the root node receives the upload message.

  The last provision date information may be stored in the Web server WS instead of being stored in the root node. For example, the Web server WS transmits a Web page in which the IP address of the content holding node introduced to the user terminal UT is described to the user terminal UT in Step S10 described later. At this time, the Web server WS uses the date information indicating the date when the Web page is transmitted as the final provision date information, and the content ID of the content X corresponding to the request from the user terminal UT and the content holding node introduced to the user terminal UT The node information is stored in association with each other. Thereby, the node processing unit 11b of the Web server WS can acquire the last provided date information corresponding to the node information of the content holding node searched by the content X search processing. In this case, the last provided date information indicates the latest date among the dates that the content holding node introduced to the user terminal UT considers to upload the content X to the user terminal UT.

  Next, the node processing unit 11b performs determination processing for determining the IP address of the node Nn to be described in the Web page based on the search result by the content X search processing (step S6). FIG. 4A is a flowchart illustrating an example of IP address determination processing. FIG. 5 is a diagram illustrating an example of a search result obtained by the content X search process. Also, in FIG. 5, three search results with different numbers of found content holding nodes are shown in (A) to (C). Also, in each search result shown in FIGS. 5A to 5C, the node information and the last provided date information of the found content holding nodes are arranged in the order of the date indicated in the last provided date information. . Such a search result is stored in a predetermined storage area of the RAM by the node processing unit 11b. Note that the content holding nodes indicated in the search result may include content holding nodes that have not yet uploaded the content X to the user terminal UT. The node information of such a content holding node is not associated with the last provision date information.

  In the IP address determination process shown in FIG. 4A, parameters such as an appropriate number of caches, an appropriate cache holding time, and an appropriate cache introduction time are used. Here, the appropriate number of caches refers to the number of content holding nodes to be held for one content when the overlay network is ON. In addition, the appropriate cache holding time refers to a time during which the content holding node storing one content should hold the content at a minimum when the overlay network is ON. That is, the appropriate cache holding time is a time that should be held at a minimum after the number of content requests exceeds the peak so as not to rapidly reduce the number of content holding nodes that store the content. In addition, the appropriate cache introduction time should be a minimum from the introduction of a content holding node that stores one content to the next introduction of the content holding node that stores the content in the overlay network ON. Say time. Each parameter of the appropriate number of caches, the appropriate cache holding time, and the appropriate cache introduction time is stored in the storage unit 12 and stored in the setting file for the P2P program. When the P2P program is activated, each parameter is read from the setting file into a predetermined storage area of the RAM and set by the node processing unit 11b.

  In the IP address determination process shown in FIG. 4A, the node processing unit 11b compares the number of search results indicated in the index information with the appropriate cache number, and determines whether the number of search results is less than the appropriate cache number. Is determined (step S61). This determination is an example of whether or not the number of location information is equal to or less than a predetermined number. Here, the number of search results is the number of content holding nodes indicated in the index information. If the node processing unit 11b determines that the number of search results is not smaller than the appropriate cache number (step S61: NO), the process proceeds to step S62. In the search result examples shown in FIGS. 5B and 5C, the number of search results is larger than the appropriate number of caches, so the process proceeds to step S62. On the other hand, if the node processing unit 11b determines that the number of search results is less than the appropriate number of caches (step S61: YES), the node processing unit 11b proceeds to step S64. In the search result example shown in FIG. 5A, since the number of search results is smaller than the appropriate cache number, the process proceeds to step S64. When the number of search results is smaller than the appropriate cache number, the content X is insufficient, so the number of content holding nodes needs to be increased. Therefore, in step S65 described later, the IP address of the node Nn not storing the content X is determined as the IP address of the node Nn introduced to the user terminal UT.

  In step S62, the node processing unit 11b calculates the elapsed time from the oldest last provided date among the last provided dates shown in the search result to the current date acquired by the clock function. In the example shown in FIG. 5, the date includes the date and time, but may be only the time. In this case, the elapsed time from the oldest last provided time among the last provided times indicated in the search result to the current time acquired by the clock function is calculated. Next, the node processing unit 11b compares the elapsed time calculated in step S62 with the appropriate cache introduction time, and determines whether or not the elapsed time is shorter than the appropriate cache introduction time (step S63). When the node processing unit 11b determines that the elapsed time is shorter than the appropriate cache introduction time (step S63: YES), the node processing unit 11b proceeds to step S64. In the search result example shown in FIG. 5B, since the elapsed time is shorter than the appropriate cache introduction time, the process proceeds to step S64. When the elapsed time is shorter than the appropriate cache introduction time, it is considered that the requests for the content X are rapidly increasing in a short time. In this case, since the content X is insufficient, it is necessary to increase the number of content holding nodes. Therefore, in step S65 described later, the IP address of the node Nn not storing the content X is determined as the IP address of the node Nn introduced to the user terminal UT.

  In step S63, the node processing unit 11b may be configured to determine whether or not the number of content holding nodes whose final provision date or time is included within a predetermined period is greater than or equal to a predetermined number. Good. Here, the predetermined period is, for example, a period retroactive to the appropriate cache introduction time from the current date and time. The predetermined number is, for example, the appropriate number of caches. If the node processing unit 11b determines that the number of content holding nodes whose final provision date or time is included within a predetermined period is greater than or equal to the predetermined number, the process proceeds to step S64. This is because requests for content X are considered to increase rapidly in a short time. On the other hand, if the node processing unit 11b determines that the number of content holding nodes whose final provision date or time is included within a predetermined period is not equal to or greater than the predetermined number, the process proceeds to step S66.

  On the other hand, when the node processing unit 11b determines that the elapsed time is not shorter than the appropriate cache introduction time (step S63: NO), the process proceeds to step S66. In the example of the search result shown in FIG. 5B, since the elapsed time is longer than the appropriate cache introduction time, the process proceeds to step S66. Note that the content holding node indicated in the search result may include a content holding node that is not associated with the final provision date information. In this case, the process of step S63 is not performed, and the process proceeds to step S66.

  In step S64, the node processing unit 11b acquires registration information registered in the management database from the management server MS and stores it in a predetermined storage area of the RAM.

  Next, the node processing unit 11b extracts registration information of the node Nn that does not store the content X corresponding to the request from the registration information acquired from the management server MS. For example, registration information of a plurality of nodes Nn other than the content holding node indicated in the search result of the content X search process is extracted. FIG. 5D is a diagram illustrating an example of registration information of a plurality of nodes Nn other than the content holding node indicated in the search result. Then, the node processing unit 11b selects one IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT as an IP address described in the Web page, among the IP addresses included in the extracted registration information of each node Nn. Determine (step S65). Here, examples of the method for determining the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT include the following methods (a) to (g).

(A) Determination Using Area Information In the case of a determination method using area information, the node processing unit 11b acquires area information indicating an area where the user terminal UT is installed. The area information of the user terminal UT is hereinafter referred to as “first area information”. In addition, the node processing unit 11b acquires area information indicating an area where the node Nn is installed. The area information of the node Nn is hereinafter referred to as “second area information”. In this case, the second area information is registration information extracted from the registration information acquired from the management server MS, and is acquired from the registration information of each node Nn that does not store the content X. The node ID of the node Nn that does not store the content X in the registration information is not shown in the search result by the content X search process. On the other hand, the first area information is determined based on, for example, an IP address assigned to the user terminal UT. This IP address is included in the request received from the user terminal UT. Further, the first area information may not be determined from the IP address assigned to the user terminal UT. In this case, the first area information may be determined from an IP address assigned to a router close to the user terminal UT. The router close to the user terminal UT is, for example, a router that is relayed first when a packet is transmitted from the user terminal UT to the Web server WS or the like. The IP address of the router close to the user terminal UT can be acquired by the user terminal UT executing a known traceroute. In some cases, the node processing unit 11b can acquire information on longitude / latitude, address, or postal code from the user terminal UT. In this case, the first area information may be determined based on longitude / latitude, address, or zip code. For example, the first area information may be determined based on a response speed from the node Nn when the user terminal UT accesses the node Nn. In this case, the second area information of the node Nn whose response speed is equal to or higher than the predetermined speed becomes the first area information of the user terminal UT.

  Then, the node processing unit 11b satisfies the condition to be introduced to the user terminal UT from the IP address of each node Nn that does not store the content X, based on the acquired first region information and second region information. The IP address of the node Nn is determined. Specifically, the node processing unit 11b compares the area where the user terminal UT is installed with the area where each node Nn not storing the content X is installed. Then, the node processing unit 11b determines the IP address of the node Nn installed in the same area as the user terminal UT as the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT. That is, the IP address of the node Nn installed in the same area as the user terminal UT is determined with priority over the IP addresses of the other nodes Nn. In other words, the IP address of the node Nn installed at the point closest to the point where the user terminal UT is installed is preferentially determined as the IP address that satisfies the condition to be introduced to the user terminal UT. As a result, the IP address of the node Nn that is close to the user terminal UT can be introduced to the user terminal UT. Therefore, the time required for data transmission / reception between the user terminal UT and the node Nn can be shortened. Therefore, the user terminal UT can quickly acquire the content X from the introduced node Nn. It is assumed that there is no node Nn installed in the same area as the user terminal UT. In this case, the node processing unit 11b determines the IP address of the node Nn installed in the area closest to the area where the user terminal UT is installed as the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT. Also good.

(B) Determination Using ISP Information In the case of a determination method using ISP information, the node processing unit 11b acquires ISP information indicating an ISP used for the user terminal UT to connect to the network NW. The ISP information of the user terminal UT is hereinafter referred to as “first ISP information”. In addition, the node processing unit 11b acquires ISP information indicating an ISP used for the node Nn to connect to the network NW. The ISP information of the node Nn is hereinafter referred to as “second ISP information”. In this case, the second ISP information is registration information extracted from the registration information acquired from the management server MS, and is acquired from the registration information of each node Nn that does not store the content X. On the other hand, the first ISP information is determined based on the IP address assigned to the user terminal UT, for example, similarly to the first area information.

  Then, the node processing unit 11b, based on the acquired first ISP information and second ISP information, from among the IP addresses of the nodes Nn that do not store the content X, the node Nn that satisfies the condition to be introduced to the user terminal UT Determine the IP address. Specifically, the node processing unit 11b includes an ISP used for connecting the user terminal UT to the network NW and an ISP used for connecting each node Nn not storing the content X to the network NW. And compare. Then, the node processing unit 11b determines the IP address of the node Nn that uses the same ISP as the user terminal UT as the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT. That is, the IP address of the node Nn that uses the same ISP as the user terminal UT is preferentially determined over the IP addresses of the other nodes Nn. As a result, the IP address of the node Nn that uses the same ISP as the user terminal UT can be introduced to the user terminal UT. Therefore, in data communication between the user terminal UT and the node Nn, occurrence of usage due to straddling between different ISPs can be suppressed. Further, the user terminal UT can quickly acquire the content X from the introduced node Nn. It is assumed that there is no node Nn that uses the same ISP as the user terminal UT. In this case, the node processing unit 11b uses the IP address of the node Nn that satisfies the condition for introducing the IP address of the node Nn that uses the ISP in the service area overlapping or close to the service area of the ISP used by the user terminal UT. It may be determined as an address.

(C) Determination using regional information and ISP information In the case of the determination method using regional information and ISP information, as in the methods (a) and (b) above, the node processing unit 11b includes first regional information, 2nd area information, 1st ISP information, and 2nd ISP information are acquired. Then, the node processing unit 11b performs processing using the area information and ISP information. FIG. 4B is a flowchart illustrating an example of processing using area information and ISP information.

  In the process shown in FIG. 4B, the node processing unit 11b searches for a node Nn that uses the same ISP as the user terminal UT from among the nodes Nn that do not store the content X (step S651). If the node processing unit 11b cannot find a node Nn that uses the same ISP as the user terminal UT (step S651: no discovery), the node processing unit 11b proceeds to step S652. On the other hand, when the node processing unit 11b has found a node Nn that uses the same ISP as the user terminal UT (step S651: found), the node processing unit 11b proceeds to step S653.

  In step S652, the node processing unit 11b searches for the node Nn installed in the same area as the user terminal UT from the nodes Nn that do not store the content X. If the node processing unit 11b cannot find the node Nn installed in the same area as the user terminal UT (step S652: no discovery), the node processing unit 11b proceeds to step S654. On the other hand, when the node processing unit 11b has found a node Nn installed in the same area as the user terminal UT (step S652: found), the process proceeds to step S655.

  In step S654, the node processing unit 11b determines the IP address of the node Nn installed in the area closest to the area where the user terminal UT is installed as the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT. .

  In step S655, the node processing unit 11b determines the IP address of the node Nn installed in the same area as the user terminal UT as the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT.

  In step S653, the node processing unit 11b searches for the node Nn installed in the same area as the user terminal UT from the nodes Nn found in step S651. If the node processing unit 11b cannot find the node Nn installed in the same area as the user terminal UT (step S653: no discovery), the node processing unit 11b proceeds to step S656. On the other hand, when the node processing unit 11b has found a node Nn installed in the same area as the user terminal UT (step S653: found), the node processing unit 11b proceeds to step S657.

  In step S656, the node processing unit 11b introduces the IP address of the node Nn of the same ISP as the user terminal UT and located in the area closest to the area where the user terminal UT is installed to the user terminal UT. Is determined as the IP address of the node Nn that satisfies the condition to be satisfied.

  In step S657, the node processing unit 11b satisfies the condition for introducing the IP address of the node Nn of the same ISP as the user terminal UT and the node Nn installed in the same area as the user terminal UT to the user terminal UT. As the IP address. Thereby, the time required for data transmission / reception between the user terminal UT and the node Nn can be shortened, and the generation of charges due to straddling different ISPs can be suppressed.

(D) Determination Using Operation Information In the determination method using operation information, the node processing unit 11b registers the registration information of each node Nn that does not store the content X from the registration information acquired from the management server MS. To extract. Then, the node processing unit 11b acquires operation information from the extracted registration information. Then, based on the acquired operation information, the node processing unit 11b determines the IP address of the node Nn that is not executing the base operation as the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT. Here, whether or not the base operation is being executed is determined based on, for example, the load factor indicated in the load information included in the operation information. For example, the node Nn whose load factor is equal to or less than a predetermined value is determined as the node Nn that is not executing the base operation. The load factor may be rounded with a certain degree of accuracy depending on the situation. For example, a load factor of less than 50% is treated as 0%. Further, whether or not the base operation is being executed is determined, for example, as a node Nn in which the base operation is not being executed by a node Nn whose bandwidth that can be allocated indicated in the band information included in the operation information is a predetermined value or more. Is done. Note that whether or not the base operation is being performed may be determined based on information other than the load information and the band information.
As described above, the IP address of the node Nn where the base operation is not being executed is determined with priority over the IP addresses of the other nodes Nn. As a result, the IP address of the node Nn that is not currently performing the base operation can be introduced to the user terminal UT. Therefore, it is possible to avoid that the execution of the base operation for providing content such as karaoke data from the router Rm to the base terminal Tm-l at each base Pm is prevented. Then, the user terminal UT can quickly acquire the content X from the introduced node Nn.

(E) Determination Using Content Retention Number Information In the case of the determination method using content retention number information, the node processing unit 11b does not store the content X from the registration information acquired from the management server MS. Nn registration information is extracted. Then, the node processing unit 11b acquires content holding number information from the extracted registration information of each node Nn. Then, the node processing unit 11b uses, as the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT, the IP address of the node Nn in which the number of stored contents indicated in the acquired content holding number information is a predetermined value or less. decide. That is, the IP address of the node Nn in which the number of stored contents is equal to or less than a predetermined value is determined with priority over the IP addresses of other nodes Nn. As a result, the IP address of the node Nn with a relatively small number of stored contents can be introduced to the user terminal UT. The node Nn with a small number of stored contents is less likely to be requested for contents from other user terminals UT or the like. Therefore, the user terminal UT can quickly acquire content from the introduced node Nn.

  The node processing unit 11b determines the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT by using at least one of the area information and the ISP information together with the operation information or the content holding number information. You may comprise. In this case, the node processing unit 11b specifies a node Nn in which the base operation is not being executed based on the operation information from among the nodes Nn that do not store the content X. Alternatively, the node processing unit 11b identifies a node Nn in which the content storage number indicated in the content retention number information is equal to or less than a predetermined value from among the nodes Nn that do not store the content X. Then, the node processing unit 11b determines the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT from any of the identified nodes Nn by any one of the methods (a) to (c).

  In addition, a plurality of IP addresses of the node Nn that satisfy the condition to be introduced to the user terminal UT may be determined by any one of the methods (a) to (c). In this case, the node processing unit 11b uses the IP address of the node Nn whose base operation is not being executed based on the operation information from among the IP addresses of the node Nn determined by any one of the methods (a) to (c). The address may be determined. Here, examples of the node Nn in which the base operation is not being executed based on the operation information include the node Nn with the lowest load factor or the node Nn with the widest bandwidth that can be allocated. Alternatively, among the IP addresses of the node Nn determined by any one of the above methods (a) to (c), the IP address of the node Nn whose stored content number indicated in the content holding number information is equal to or less than a predetermined value May be determined. Here, as an example of the node Nn in which the number of stored contents is equal to or less than a predetermined value, the node Nn having the smallest number of stored contents can be cited.

  The node processing unit 11b may be configured to determine the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT using the operation information and the content holding number information. In this case, the node processing unit 11b specifies a node Nn in which the base operation is not being executed based on the operation information from among the nodes Nn that do not store the content X. Subsequently, the node processing unit 11b further specifies a node Nn whose stored number of contents indicated in the content holding number information is equal to or less than a predetermined value from the specified nodes Nn. Then, the node processing unit 11b determines the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT from among the further specified nodes Nn. Also in this determination, the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT may be determined by any one of the methods (a) to (c).

(F) Determination using other information In addition to the information used in any of the methods (a) to (e) above, for example, the file size of the content, the rank of the user of the user terminal UT, and upload from the node Nn The data amount or the number of lines used by the node Nn may be used.

  For example, the file size of the content requested from the user terminal UT may be as large as a predetermined size or larger. In this case, the node processing unit 11b satisfies the condition for introducing the IP address of the node Nn in which the storage capacity of the content storage area is greater than or equal to a predetermined capacity among the nodes Nn not storing the content X to the user terminal UT. It is determined as the IP address of the node Nn. In this case, information indicating the storage capacity of the content storage area of each node Nn is transmitted from the node Nn to the management server MS and registered in the management database when the node Nn participates in the overlay network ON, for example.

  Further, for example, there are cases where it is desired to change the service level for each rank of the user. In this case, the node processing unit 11b, among each node Nn that does not store the content X, the IP of the node Nn that satisfies the condition for introducing the IP address of the stable node Nn to the user terminal UT of the user with a higher rank. Determine as an address. Here, examples of the stable node Nn include a node Nn that is a resident node and has a load factor load factor indicated by the load information equal to or less than a predetermined value, or a node Nn whose allocated bandwidth is equal to or greater than a predetermined value. It is done. The rank of the user is determined by, for example, the presence / absence of fee payment, the amount thereof, or the purchase history of the product. For example, when the user is a free member, the rank of the user is low. On the other hand, when the user is a paid member, the user rank is high.

  Further, depending on the ISP, there may be a restriction on uploading of content from the node Nn. In this case, the node processing unit 11b determines that the node Nn in which the actually uploaded data amount is smaller than the preset upload limit amount of the ISP to be used, among the nodes Nn that do not store the content X, It is determined as the IP address of the node Nn that satisfies the condition to be introduced to the terminal UT. Here, information indicating the amount of data actually uploaded is transmitted from the node Nn and registered in the management database, for example, when the node Nn participates in the overlay network ON and thereafter at a predetermined time interval.

  In addition, there may be an upper limit on the number of lines that can be used simultaneously by the node Nn. In this case, the node processing unit 11b satisfies the condition for introducing the node Nn whose number of lines being used simultaneously is a predetermined number or less among the nodes Nn that do not store the content X to the user terminal UT. It is determined as the IP address of Nn. Here, information indicating the number of lines used by the node Nn is transmitted from the node Nn and registered in the management database, for example, when the node Nn participates in the overlay network ON and thereafter at a predetermined time interval.

  Note that there is a case where the number of nodes Nn that satisfy the condition to be introduced to the user terminal UT cannot be reduced to one by any one of the methods (a) to (e). In this case, the IP address of one node Nn may be determined using random or other information. Examples of other information include the content file size, the user rank of the user terminal UT, the amount of data uploaded from the node Nn, the number of lines used by the node Nn, and the like.

  Next, in step S66, the node processing unit 11b determines whether or not the number of content holding nodes whose final provision date is included in a period that is back from the current date and time is the appropriate cache number or more. To do. That is, it is determined whether or not the number of search results accessed within the appropriate cache retention time is equal to or greater than the appropriate cache number. If the node processing unit 11b determines that the number is more than the appropriate cache number (step S66: YES), the process proceeds to step S67. In the example of the search result shown in FIG. 5C, the number of caches is equal to or more than appropriate, and the process proceeds to step S67. On the other hand, if the node processing unit 11b determines that the number of caches is not equal to or greater than the appropriate cache number (step S66: NO), the process proceeds to step S68.

  In step S67, the node processing unit 11b selects the IP address of the content holding node with the oldest last provided date among the content holding nodes that include the last provided date within the period that is the appropriate cache holding time from the current date and time. The IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT is determined. In the search result example shown in FIG. The IP addresses of the 12 node N16 are determined. As a result, access to the content holding nodes from a plurality of user terminals UT can be distributed, and access from the user terminals UT can be avoided from being concentrated on specific content holding nodes.

  On the other hand, in step S68, the node processing unit 11b sorts, for example, the node information of the content holding nodes indicated in the search result in descending order by the last provided date. In other words, the dates are sorted in the order of newest. Then, the node processing unit 11b determines the IP address of the content holding node having the appropriate number of caches from the top sorted in descending order as the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT.

  In step S67 and step S68, the method of any one of the above (a) to (f) may be performed before determining the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT. Good. In this case, the node processing unit 11b acquires registration information from the management server MS. Then, the node processing unit 11b extracts the registration information of each node Nn that stores the content X from the registration information acquired from the management server MS. For example, the registration information of the content holding node indicated in the search result by the content X search process is extracted. That is, in this case, the object to be extracted is different from that in step S65. Then, the node processing unit 11b specifies a plurality of content holding nodes from among the extracted content holding nodes using any one of the methods (a) to (f). The process of step S67 or step S68 is performed on the plurality of content holding nodes thus identified. As a result, the IP address of the content holding node that satisfies the condition to be introduced to the user terminal UT is determined.

  Then, the node processing unit 11b responds to the HTTP server unit 11a with the IP address of the node Nn determined in step S6 (step S7). Specifically, the node processing unit 11b stores the determined IP address of the node Nn in a predetermined storage area of a RAM accessible by the HTTP server unit 11a.

  Next, when acquiring the IP address returned from the node processing unit 11b, the HTTP server unit 11a determines whether or not the URL extracted in step S3 is still present (step S8). For example, when the content X is composed of a plurality of files, the URL of each file constituting the content X is extracted from the Web page. When the HTTP server unit 11a determines that the URL extracted in step S3 is still present (step S8: YES), the HTTP server unit 11a returns to step S4 and performs the same processing as described above. On the other hand, if the HTTP server unit 11a determines that there is no URL extracted in step S3 (step S8: NO), the process proceeds to step S9.

  In step S9, the HTTP server unit 11a replaces the domain name included in the URL of the content X described in the Web page acquired in step S2 with the IP address acquired from the node processing unit 11b. Generate a page. FIG. 5E is a diagram showing a description example of HTML constituting the Web page acquired in step S2. In the example shown in FIG. 5E, the domain name “imagesv.jp” in the URL “http://imagesv.jp/image01.jpg” of the content X is changed to the node processing unit 11b by the processing in step S11. The IP address “192.168.90... In this way, a Web page describing the IP address is generated. Here, “image01.jpg” indicates the file name of the content X. When the content X is composed of a plurality of files, the domain name included in the URL corresponding to each file is replaced with the corresponding IP address.

  Next, the HTTP server unit 11a of the Web server WS transmits the Web page generated in Step S9 as a response to the user terminal UT (Step S10).

  Next, the web browser of the user terminal UT receives a web page from the web server WS. Then, the web browser of the user terminal UT accesses the HTTP server unit 31b of the node Nn using the HTTP protocol according to the IP address described in the web page. Then, the Web browser of the user terminal UT transmits a request for the content X to the HTTP server unit 31b of the node Nn (Step S11). This request includes a URL in which the domain name is replaced with the IP address. This URL is “http: //192.168.90... /Image01.jpg” in the example of FIG.

  Next, when receiving the request from the Web browser of the user terminal UT, the HTTP server unit 31b of the node Nn requests the content X corresponding to this request from the node processing unit 31c of the node Nn (step S12).

  Next, the node processing unit 31c determines whether or not the requested content X is stored in the content storage area of the storage unit 31 (step S13). When the node processing unit 31c determines that the content X is not stored in the content storage area (step S13: NO), the process proceeds to step S14. On the other hand, when the node processing unit 31c determines that the content X is stored in the content storage area (step S13: YES), the process proceeds to step S16.

  In step S14, the node processing unit 31c performs a content X search process. As a result, the node processing unit 31c acquires index information from the root node of the content X. Since the content X search process is the same as that in step S5, a description thereof will be omitted. The content ID used in the content X search process is acquired, for example, when the node processing unit 31c inquires of the Web server WS. Alternatively, the content ID is acquired by calculating the hash of the URL before the search process by setting the content ID itself as the hash value of the URL. Alternatively, it may be included in a request transmitted from the Web browser to the HTTP server unit 31b of the node Nn.

  Next, the node processing unit 31c accesses the content holding node according to the IP address of the content holding node included in the index information acquired in step S14. Then, the node processing unit 31c acquires the content X from the content holding node (step S15), and proceeds to step S16. The content X acquired from the content holding node is stored in a content storage area provided in the storage unit 31. The node processing unit 31c that stores the content X in this way performs a publishing process. This publishing process is a process for disclosing that the content is stored to other nodes Nn. In this publishing process, the node processing unit 31c generates a publish message. The publish message includes the content ID of the content X and the node information of the node Nn that stores the content. The node processing unit 31c transmits the generated publish message to the root node of the content by DHT routing. The root node that has received the publish message stores a set of the content ID of the content X and the IP address of the node Nn as index information. Thereby, in the overlay network ON, the content holding node for storing the content X is increased by one.

  In step S16, the node processing unit 31c transfers the requested content X to the HTTP server unit 31b. Specifically, the node processing unit 31c stores the content X in a predetermined storage area of a RAM accessible by the HTTP server unit 31b.

  Next, the HTTP server unit 31b transmits the content X as a response to the user terminal UT (step S17).

  Next, the Web browser of the user terminal UT receives the content X from the HTTP server unit 31b node processing unit 31c of the node Nn. Then, the web browser of the user terminal UT performs a process of displaying or outputting the received content X (step S18).

  As described above, according to the embodiment, the Web server WS determines the IP address of the node Nn that satisfies the condition to be introduced to the user terminal UT, based on the search result of the content requested from the user terminal UT. . Then, the Web server WS transmits a Web page in which the determined IP address is described to the user terminal UT. Therefore, the user terminal UT can efficiently acquire the content distributed by the overlay network ON using the IP address described in the Web page transmitted from the Web server WS without installing the P2P program. .

  In addition, every time there is a request from the user terminal UT, a content search process is performed, and an IP address described in the Web page is determined based on the search result. Therefore, access concentration to a specific node Nn can be reduced.

  Also, there is a case where some content is insufficient in the overlay network ON. In this case, the web page describing the IP address of the node Nn that does not store the requested content is transmitted to the user terminal UT. Therefore, the node Nn not storing the requested content acquires this content from the content holding node via the overlay network ON in order to provide the content to the user terminal UT. As a result, the number of content holding nodes that store the content can be increased.

  By the way, in a conventional client-server system, a Web page transmitted from a Web server to a user terminal has contents such as images, sounds, and videos embedded in a base page. Then, the Web server also transmits content such as images, sounds, and videos embedded in the base page to the user terminal. Since the base page is a text page made of HTML or the like, the amount of data is larger than that of content such as video. In the present embodiment, the Web server WS transmits a base page to the user terminal UT. However, the content provided on the Web page is provided to the user terminal UT by the node Nn, not the Web server WS. Therefore, in the present embodiment, it is possible to reduce the load on the Web server WS.

  In the above embodiment, the Web server WS is configured to include the HTTP server unit 11a and the node processing unit 11b. As another example, the Web server WS may be configured not to include the node processing unit 11b but to include the node processing unit 11b in a device such as the node Nn. In this case, the Web server WS does not participate in the overlay network ON. In this case, the exchange of information between the HTTP server unit 11a of the Web server WS and the node processing unit 11b provided in another apparatus is the same as the process shown in FIG.

  In the above embodiment, the router Rm is described as an example of the information processing apparatus in the present invention. However, the information processing apparatus may be a server connected to the network NW. Further, the information processing apparatus may basically be a device such as a gateway that is regularly connected to the network NW.

  In the above embodiment, the peer-to-peer network using DHT is applied to the overlay network ON. However, the present invention is not limited to this. For example, a system using another overlay network may be applied. As a peer-to-peer system that does not use DHT, for example, there is a hybrid peer-to-peer system.

11, 21, 31 Control unit 12, 22, 33 Storage unit 13, 23, 34a, 34b Communication unit 32 Buffer memory WS Web server MS management server Rm Router UT User terminal Nn Node NW Network ON Overlay network S Content distribution system

Claims (10)

A server device capable of communicating with the information processing device in a distribution system in which an overlay network is configured by a plurality of information processing devices capable of communicating with each other via a network, and content is stored in one or more of the information processing devices,
Receiving means for receiving a request for predetermined content from a first terminal device not participating in the overlay network;
Search means for searching the overlay network for the location of the information processing apparatus that stores the content corresponding to the request received by the receiving means;
Determination means for determining the location information indicating the location of the information processing apparatus, which is location information described in a Web page, based on a search result by the search means;
Generating means for generating a web page in which the location information determined by the determining means is described;
Transmitting means for transmitting the web page generated by the generating means to the first terminal device;
A server device comprising:   The determining means, when a plurality of the location information is searched by the search means, the location information satisfying a condition to be introduced to the first terminal device from the plurality of location information, The server device according to claim 1, wherein the server device is determined as location information described in a Web page. The server device
First acquisition means for acquiring first area information indicating an area where the first terminal device is installed;
Second acquisition means for acquiring second area information indicating an area where the information processing apparatus is installed;
With
The determination means is a distance from the area where the first terminal device is installed based on the first area information acquired by the first acquisition means and the second area information acquired by the second acquisition means. 3. The server according to claim 2, wherein the location information of the information processing device installed in an area close to is preferentially determined as the location information that satisfies a condition to be introduced to the first terminal device. 4. apparatus. The server device
Third acquisition means for acquiring first ISP information indicating an ISP (Internet Service Provider) used for the first terminal device to connect to the network;
Fourth acquisition means for acquiring second ISP information indicating an ISP used for the information processing apparatus to connect to the network;
With
The determination unit uses the same ISP as the first terminal device based on the first ISP information acquired by the third acquisition unit and the second ISP information acquired by the fourth acquisition unit. 4. The server device according to claim 2, wherein the location information of the processing device is preferentially determined as the location information that satisfies a condition to be introduced to the first terminal device. A second terminal device different from the first terminal device is connected to the information processing device via communication means,
The information processing device controls an operation of acquiring content to be transmitted to the second terminal device from another information processing device via the overlay network, or an operation of transmitting the content to the second terminal device. With control means,
The server device includes fifth acquisition means for acquiring operation information indicating whether an operation controlled by the control unit of the information processing apparatus is being executed,
The determination means is based on the operation information acquired by the fifth acquisition means, and the location information that satisfies the condition for introducing the location information of the information processing apparatus in which the operation is not being executed to the first terminal device. The server apparatus according to any one of claims 2 to 4, wherein the server apparatus is determined preferentially as information. The server device includes sixth acquisition means for acquiring access information indicating a date or time when the information processing device accesses another information processing device,
The determining means is based on the access information acquired by the sixth acquiring means, and the location information that satisfies the condition for introducing the location information of the information processing apparatus with the old date or time to the first terminal device. The server apparatus according to any one of claims 2 to 5, wherein the server apparatus determines the information preferentially. Seventh acquisition means for acquiring the location information from a management device that manages the location information indicating the location of the information processing device participating in the overlay network;
First determination means for determining whether or not the number of the location information searched by the search means is equal to or less than a predetermined number,
When the first determination unit determines that the number of the location information searched by the search unit is equal to or less than a predetermined number, the determination unit acquires the location information acquired by the seventh acquisition unit. The location information of an information processing apparatus that does not store the content corresponding to the request is determined as location information described in the Web page. The server device according to claim 1. Seventh acquisition means for acquiring the location information from a management device that manages the location information indicating the location of the information processing device participating in the overlay network;
The date or time when the information processing device corresponding to the location information searched by the search means provided content to another information processing device, or the date or time when the location information was provided to the other information processing device. An eighth acquisition means for acquiring provided information indicating time;
With
Second determination means for determining whether or not the number of the information processing devices whose date or time indicated by the provision information acquired by the eighth acquisition means is included in a predetermined period is equal to or greater than a predetermined number;
When the second determination unit determines that the number of the information processing devices whose date or time indicated in the provision information acquired by the eighth acquisition unit is included in a predetermined period is equal to or greater than a predetermined number And the determination unit stores the location information of the information processing apparatus that does not store the content corresponding to the request among the predetermined number of the location information acquired by the seventh acquisition unit in the Web page. The server apparatus according to any one of claims 1 to 6, wherein the server apparatus is determined as location information to be described. A computer included in a server device capable of communicating with the information processing device in a distribution system in which an overlay network is configured by a plurality of information processing devices capable of communicating with each other via a network and content is stored in one or more of the information processing devices In addition,
Receiving a request for predetermined content from a first terminal device not participating in the overlay network;
Searching the overlay network for the location of the information processing apparatus that stores the content corresponding to the received request;
Determining location information to be described in a Web page based on the search result, the location information indicating the location of the information processing apparatus;
Generating a web page in which the determined location information is described;
Transmitting the generated web page to the first terminal device;
Page transmission program to execute. A web page transmission method in a distribution system in which an overlay network is configured by a plurality of information processing devices that can communicate with each other via a network, and content is stored in one or more of the information processing devices,
A server device receiving a request for predetermined content from a first terminal device not participating in the overlay network;
The server device searches the overlay network for the location of the information processing device that stores the content corresponding to the received request;
The server device, based on the result of the search, determining the location information to be described in a Web page and indicating the location of the information processing device;
The server device generating a Web page in which the determined location information is described;
The server device transmitting the generated web page to the first terminal device;
The page transmission method characterized by including.

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