JP2012050018A - Distribution system, information processor, information processing program and content inputting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a distribution system capable of dispersively preserving contents distributed from a distribution device which does not belong to an overlay network in the overlay network and efficiently operating them, and to provide an information processor, an information processing program and a content inputting method.SOLUTION: The information processor retrieves a location of a prescribed content preserved in the overlay network. When the prescribed content cannot be detected as a result, the content is acquired from the distribution device preserving the original of the content distributed in the overlay network. The information processor determines whether the acquired content satisfies an input condition for being inputted to the overlay network or not. When the content is determined to satisfy the input condition, the prescribed content is inputted to the overlay network as the content which can be acquired in the overlay network.

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 participating in an overlay network composed of a plurality of node devices. In the overlay network, the node device can acquire content data from other node devices. Hereinafter, the content data is referred to as “content”. In such a peer-to-peer type distribution system, it is possible to reduce load concentration on a server such as a client-server type distribution system. Further, the location of the content distributed and stored in the overlay network can be efficiently searched using a distributed hash table as disclosed in, for example, Patent Document 1.

JP 2006-197400 A

  By the way, for example, content distributed by a client-server distribution system or the like may be newly input into an overlay network in a peer-to-peer distribution system. Here, “content input” means that new content is stored in the node device as content that can be acquired by the overlay network. Further, the content to be input is determined by a request from a provider or a viewer of this content, for example.

  However, for example, in the case of a peer-to-peer distribution system in which node devices frequently participate in or leave the overlay network, the number of node devices that store content in the overlay network may be reduced. In this case, the total storage capacity that is the sum of the storage capacities of all the node devices is reduced. For this reason, when all the contents to be input are input to the overlay network, it may be difficult to operate the peer-to-peer distribution system efficiently by distributing and storing all the contents.

  Accordingly, the present invention has been made in view of the above points and the like, and distribution that can efficiently operate by distributing and storing content distributed from a distribution device that does not belong to the overlay network in the overlay network. It is an object to provide a system, an information processing apparatus, an information processing program, a content input method, and the like.

  In order to solve the above-described problem, the invention according to claim 1 is an overlay network including a plurality of information processing devices that can communicate with each other via a network, and the information processing device receives content from another information processing device. In the distribution system configured to acquire the information, the information processing device searches for the location of the predetermined content stored in the information processing device in the overlay network, and the predetermined content by the search unit. The acquisition unit that acquires the content from a distribution device that stores the original content distributed on the overlay network, and the input that the content acquired by the acquisition unit is input to the overlay network. Judgment to determine whether the condition is met And a control unit that executes control to input the predetermined content to the overlay network as content that can be acquired by the overlay network when the determination unit determines that the input condition is satisfied. It is characterized by providing.

  According to a second aspect of the present invention, in the distribution system according to the first aspect, unique identification information for identifying the content in the overlay network is assigned to the content stored in the information processing apparatus in the overlay network. The search means sends a request including location information that is location information extracted from a web page transmitted from a web server and that indicates the location of the predetermined content stored in the distribution device. Based on the receiving means received from the browser and the location information included in the received request, identification information for identifying the predetermined content from the content stored in the information processing apparatus in the overlay network is generated. Generating means, wherein the search means is the generated controller. Characterized by searching the location of the predetermined content based on the identification information of Ntsu.

  According to a third aspect of the present invention, in the distribution system according to the second aspect, the distribution system includes a management server that manages input of the content, and the control unit is included in the received request. The information is transmitted to the management server, and when the management server receives the location information transmitted from the information processing device, the management server acquires the predetermined content from the distribution device based on the location information. Means, and input means for inputting the predetermined content acquired by the second acquisition means to the overlay network.

  According to a fourth aspect of the present invention, in the distribution system according to the second or third aspect, the location information is a URI (Uniform Resource Identifier) of the predetermined content.

  According to a fifth aspect of the present invention, in the distribution system according to any one of the first to fourth aspects, when the predetermined content is acquired from the distribution device by a client-server method, It is determined that the charging condition is satisfied.

  According to a sixth aspect of the present invention, in the distribution system according to any one of the first to fourth aspects, the information processing apparatus is a third acquisition unit that acquires size information indicating a data size of the predetermined content. And based on the size information acquired by the third acquisition unit, the determination unit determines that the input condition is satisfied when the data size of the predetermined content is equal to or greater than a predetermined data size. It is characterized by doing.

  According to a seventh aspect of the present invention, in the distribution system according to any one of the first to fourth aspects, the information processing apparatus includes a fourth acquisition unit that acquires current date information indicating a current date, and the predetermined information. 5th acquisition means which acquires the publication period information which shows the publication period of this content, The said current date information acquired by the said 4th acquisition means, and the said publication period acquired by the said 5th acquisition means Based on the information, the determination unit determines that the input condition is satisfied when the current date is within a period of disclosure of the predetermined content.

  According to an eighth aspect of the present invention, in the distribution system according to any one of the first to fourth aspects, the information processing apparatus distributes the date on which the predetermined content can be distributed by the distribution apparatus. Further comprising sixth acquisition means for acquiring possible information, and based on the distributable information acquired by the sixth acquisition means, the determination means, when a predetermined period has not elapsed since the date, It is determined that it satisfies.

  According to a ninth aspect of the present invention, in the distribution system according to any one of the first to fourth aspects, the information processing apparatus obtains distribution apparatus information indicating a predetermined distribution apparatus. And based on the distribution device information acquired by the seventh acquisition unit, the determination unit satisfies the input condition when the distribution device that distributes the predetermined content is indicated in the distribution device information. It is characterized by determining.

  According to a tenth aspect of the present invention, in the distribution system according to any one of the first to fourth aspects, the information processing apparatus further includes a measurement unit that measures a distribution speed of the distribution apparatus, and the measurement unit Based on the distribution speed measured by the above, the determination means determines that the input condition is satisfied when the distribution speed of the distribution apparatus is equal to or lower than a predetermined distribution speed.

  The invention according to claim 11 is an overlay network including a plurality of information processing devices that can communicate with each other via a network, and the information processing device is configured to acquire content from another information processing device. The information processing apparatus included in the distribution system, wherein the information processing apparatus searches for a location of predetermined content stored in the information processing apparatus in the overlay network, and the predetermined information is obtained by the search means. When the content cannot be found, an acquisition unit that acquires the content from a distribution device that stores the original content distributed on the overlay network, and the content acquired by the acquisition unit is input to the overlay network. Judgment to determine whether or not the input conditions are met And a control unit that executes control to input the predetermined content to the overlay network as content that can be acquired by the overlay network when the determination unit determines that the input condition is satisfied. It is characterized by providing.

  The invention according to claim 12 is an overlay network composed of a plurality of information processing devices that can communicate with each other via a network, and is configured such that the information processing device acquires content from another information processing device. Searching the computer included in the distribution system for the location of the predetermined content stored in the information processing apparatus in the overlay network, and when the predetermined content is not found, the computer distributes the computer in the overlay network Acquiring the content from a distribution device that stores the original of the content; determining whether the acquired content satisfies an input condition for input to the overlay network; and determining that the input condition is satisfied If the predetermined The content is an information processing program for executing the steps of: performing control for charging to the overlay network as obtainable content by the overlay network.

The invention according to claim 13 is an overlay network composed of a plurality of information processing devices that can communicate with each other via a network, and the information processing device is configured to acquire content from another information processing device. A content input method in a distribution system, wherein the information processing device searches the location of predetermined content stored in the information processing device in the overlay network, and the information processing device Acquiring the content from a distribution device that stores the original content distributed on the overlay network when the predetermined content cannot be found; and the information processing device, wherein the acquired content is: Inject into the overlay network Determining whether input condition is satisfied or not,
When it is determined that the information processing apparatus satisfies the input condition, executing a control for inputting the predetermined content to the overlay network as content that can be acquired by the overlay network; It is characterized by including.

  According to the invention described in claims 1, 11 to 13, predetermined content that is not stored in the information processing apparatus in the overlay network is input to the overlay network only when the input condition to input to the overlay network is satisfied. Therefore, even when the number of information processing apparatuses that store content in the overlay network is reduced, it is possible to efficiently operate the distribution system by distributing and storing content in the overlay network.

  According to the second aspect of the present invention, the content identification information is generated based on the location information included in the Web page. Therefore, the description of the Web page is used to describe the identification information of the content to be input to the overlay network. It is possible to save the trouble of changing.

  According to the third aspect of the present invention, the processing load of the information processing apparatus can be reduced by the content being input by the management server.

  According to the invention described in claim 4, since the content identification information is generated based on the URI of the content included in the Web page, the description of the Web page is used to describe the identification information of the content to be input to the overlay network. It is possible to save the trouble of changing.

  According to the fifth aspect of the present invention, this information can be input to the overlay network by the information processing apparatus that has acquired the predetermined content from the distribution apparatus by the client-server method.

  According to the sixth aspect of the present invention, it is possible to reduce the processing load of the distribution apparatus by inputting content having a data size of a predetermined size or more to the overlay network.

  According to the seventh aspect of the present invention, only contents within the publication period can be input to the overlay network.

  According to the eighth aspect of the present invention, recently released or updated content can be input to the overlay network. Therefore, it can be expected that this content will be used in the overlay network for a long period after the input.

  According to the ninth aspect of the present invention, it is possible to reduce the processing load of a specific distribution device.

  According to the tenth aspect of the present invention, it is possible to reduce the processing load of a distribution device whose distribution speed is a predetermined speed or less.

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 a node Nn. It is a flowchart which shows the acquisition process of the content in the node process part 11c.

  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 includes a plurality of node devices Nn (n = 1, 2, 3,... K) and the like. The node device is hereinafter referred to as “node”. A node is an example of an information processing apparatus according to the present invention. Each node Nn is connected to a network NW composed of the Internet or the like. A plurality of nodes Nm (m = i, ii, iii... Γ), a Web server WS, and a management server MS are connected to the network NW. The web server WS is an example of a distribution device according to the present invention. The management server MS is a server that manages content input. In the content distribution system S, an overlay network ON1 and an overlay network ON2 are formed. The overlay network ON1 is configured by participation of a plurality of nodes Nn that can communicate with each other via the network NW. On the other hand, the overlay network ON2 is configured by participation of a plurality of nodes Nm that can communicate with each other via the network NW. The overlay network ON1 and the overlay network ON2 are logical networks that form virtual links, respectively. The overlay network ON1 and the overlay network ON2 are each realized by a specific algorithm, for example, an algorithm using a distributed hash table. Hereinafter, the distributed hash table is referred to as “DHT (Distributed Hash Table)”. Here, to participate in the overlay network means to operate in a state in which various messages can be transmitted to and received from other nodes Nn via the overlay network based on the routing table using DHT. As a result, the node Nn can send and receive messages to and from other nodes Nn based on the routing table using the DHT for the overlay network ON1. On the other hand, the node Nm can send and receive messages to and from other nodes Nm based on the routing table using the DHT for the overlay network ON2. Thus, the overlay network ON1 and the overlay network ON2 are independent networks. 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.

  A node ID is assigned to each node Nn participating in the overlay network ON1. This node ID is unique identification information for identifying the node Nn from among the nodes Nn participating in the overlay network ON1. On the other hand, a node ID is assigned to each node Nm participating in the overlay network ON2. This node ID is unique identification information for identifying the node Nm from among the nodes Nm participating in the overlay network ON2. Since the mechanisms of the overlay network ON1 and the overlay network ON2 are the same, the following description will be focused on the overlay network ON1.

  Various contents having different contents are distributed and stored in the plurality of nodes Nn participating in the overlay network ON1. Examples of content include moving image content that can be viewed by a user, such as a movie or a program. Further, a content ID is assigned to each content stored in each node Nn in the overlay network ON1. The content ID is unique identification information for identifying the content from the content stored in the node Nn by the overlay network ON1. Note that the node ID and the content ID are generated by, for example, a hash function common to the overlay network ON1.

  Here, the node Nn that stores the content is hereinafter referred to as a “content holding node”. Information indicating 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. For example, the root node is determined to be 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 ON1. In this case, the node Nn first performs a search process for searching for the location of the predetermined content stored in the content holding node in the overlay network ON1. Here, the predetermined content is, for example, content selected as an acquisition target by the node Nn. This predetermined content is hereinafter referred to as “content to be acquired”. The node Nn that performs the search process is hereinafter referred to as a “user node”. The search process is performed based on the content ID of the content to be acquired. Specifically, the user node generates a content location inquiry message in the 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 addresses of one or more content holding nodes that store the content to be acquired. 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.

  On the other hand, the user node may not be able to find the content to be acquired from the overlay network ON1 by the search process. As an example of this case, there is a case where the content to be acquired has not yet been put into the overlay network ON1. In this case, the node information of the content holding node of the content to be acquired is not stored in the root node that has received the content location inquiry message. Therefore, the root node returns a message indicating that there is no content holding node storing the content to be acquired to the user node. When the content to be acquired cannot be found in this way, the user node accesses the Web server WS that stores the content. In the present embodiment, the Web server WS does not belong to the overlay network ON1. Belonging indicates that the Web server WS is participating in the overlay network ON. Then, the user node requests content from the Web server WS and acquires the content from the Web server WS. In this way, when the content acquired from the Web server WS satisfies the input condition for input to the overlay network ON1, this content is input to the overlay network ON1. Accordingly, the content acquired from the Web server WS becomes content that can be acquired by the overlay network ON1. The charging conditions will be described later.

[ 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 1, a storage unit 2, a communication unit 3, and the like. The control unit 1, the storage unit 2, and the communication unit 3 are connected to each other via a bus 4. Note that the Web server WS may include a plurality of servers such as an application server and a database server.

  The storage unit 2 is composed of, for example, a hard disk drive. The storage unit 2 stores an operating system, a server program, and the like. In the content storage area provided in the storage unit 2, content that can be provided to the node Nn is stored in a predetermined file format. The content includes content that has been input to the overlay network ON1 and content that has not been input to the overlay network ON1. Examples of content files include wma files, wmv files, asf files, and the like. The storage unit 2 stores Web pages that can be provided to the node Nn. The Web page is composed of a structured document file described in HTML (Hyper Text Markup Language), XML (Extensible Markup Language), or the like. In addition, an identifier of a player that is software for reproducing content is described in the Web page. Further, location information indicating the location of content that can be provided to the node Nn is described in the Web page. As an example of the location information, there is a URL (Uniform Resource Locator) of content. The URL is an example of a URI. The URI includes a URL that identifies the location of the resource and a URN that identifies the name of the resource. This URL includes the file path of the content. The content file path is information for specifying the position of the content storage area. The Web page may be configured such that the URL of the content metafile is described as location information. The content metafile is a text file for the Web browser to access the content from the Web page. For this reason, the content URL is described in the content metafile. Examples of content metafiles include a wax file, a wvx file, and an asx file. By using such a content metafile, the Web browser activates the player indicated on the Web page and enables streaming playback of the content.

  The communication unit 3 controls communication of information with the node Nn and the like through the network NW.

  The control unit 1 includes a CPU having a calculation function, a working RAM, a ROM, and the like. The control unit 1 reads out and executes a program stored in the storage unit 2 or the like, and performs processing to be described later.

[ 3. Configuration and function of node Nn ]
Next, the configuration and function of the node Nn will be described with reference to FIG. FIG. 2B is a block diagram illustrating a schematic configuration example of the node Nn. As shown in FIG. 2B, the node Nn includes a control unit 11, a storage unit 12, a buffer memory 13, a decoder unit 14, a video processing unit 15, a display unit 16, an audio processing unit 17, a speaker 18, and a communication unit 19. And an input unit 19a and the like. The control unit 11, the storage unit 12, the buffer memory 13, the decoder unit 14, the video processing unit 15, the display unit 16, the audio processing unit 17, the communication unit 19, and the input unit 19a are connected to each other via a bus 19b. Yes. As the node Nn, a personal computer, an STB (Set Top Box), or the like is applicable.

  The storage unit 12 is composed of, for example, a hard disk drive. The storage unit 12 stores an operating system, a web browser program, a player program, a node processing program, and the like. The node processing program or the like may be downloaded from a predetermined server connected to the network NW, for example. Alternatively, the node processing program or the like may be recorded on a recording medium and read via a drive of the recording medium, for example. The storage unit 12 stores content acquired from the content holding node or the Web server WS. The storage unit 12 stores the IP address and port number of the Web server WS. Further, the storage unit 12 of the node Nn participating in the overlay network ON1 stores a routing table using DHT.

  The buffer memory 13 buffers the received content. The decoder unit 14 performs decoding processing such as data expansion and decoding of video data and audio data included in the content. The video processing unit 15 performs a predetermined drawing process on the video data decoded by the decoder unit 14 and reproduces and outputs it as a video signal. The display unit 16 displays a video or the like on the display based on the video signal reproduced and output from the video processing unit 15. The display unit 16 displays the image decoded by the decoder unit 14. The audio processing unit 17 performs D (Digital) / A (Analog) conversion of the audio data decoded by the decoder unit 14 into an analog audio signal, and then amplifies this by an amplifier to reproduce and output. The speaker 18 outputs the audio signal reproduced and output from the audio processing unit 17 as a sound wave. The communication unit 19 controls communication of information with the Web server WS and other nodes Nn 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 search unit, an acquisition unit, a determination unit, a control unit, a reception unit, a generation unit, a measurement unit, and third to seventh acquisition units in the present invention. The control unit 11 has a clock function and a timer function. In addition, the control unit 11 operates as the Web browser 11a when the CPU executes the Web browser program stored in the storage unit 12 or the like. The web page acquired from the web server WS by the web browser 11a is displayed on the display. Further, the control unit 11 operates as the player 11b when the CPU executes the player program stored in the storage unit 12 or the like. The player 11b controls the decoder unit 14 and the like to reproduce the content. Further, the control unit 11 operates as the node processing unit 11c when the CPU executes a node processing program stored in the storage unit 12 or the like. The node processing unit 11c performs transmission / reception of various messages via the overlay network ON1, processing according to the received message, and the like. Furthermore, the node processing unit 11c has a relay function for relaying between the Web browser 11a and the Web server WS. With this relay function, a request from the Web browser 11a is transferred to the Web server WS via the node processing unit 11c. Also, with this relay function, the response from the Web server WS is transferred to the Web browser 11a via the node processing unit 11c.

  Note that the processing of the Web browser 11a and the node processing unit 11c is executed by one CPU by multitasking or multicore. Alternatively, the processing of the web browser 11a and the node processing unit 11c may be configured to be executed by two CPUs using two CPUs.

[4. Operation of Content Distribution System S]
Next, the operation of the content distribution system S according to the present embodiment will be described.

(4.1 Content input operation)
First, content input operation will be described with reference to FIG. FIG. 3 is a flowchart showing content acquisition processing in the node processing unit 11c. As a premise of the operation described below, it is assumed that the node Nn participates in the overlay network ON1. Further, it is assumed that the Web page received from the Web server WS by the Web browser 11a is displayed on the display unit 16 of the node Nn. This web page is a page for viewing content selected as an acquisition target by the user via the input unit 19a, for example. In addition, this Web page includes, for example, the URL of the content or the URL of the metafile of the content.

  The process illustrated in FIG. 3 is started when a user issues a content reproduction instruction via the input unit 19a in a state where a Web page is displayed, for example. In response to this reproduction instruction, the Web browser 11a transmits a request for the content to be acquired to the node processing unit 11c. Alternatively, a request for content to be acquired may be transmitted to the node processing unit 11c on the condition that the Web browser 11a has received a Web page. This request is an HTTP (HyperText Transfer Protocol) request. The content request includes the URL of the content extracted from the Web page. Note that the Web page may include the URL of the content metafile. In this case, the Web browser 11a first acquires the content metafile and extracts the URL of the content from the metafile. Then, the web browser 11a transmits a request including the URL of the extracted content to the node processing unit 11c.

  First, the node processing unit 11c receives a content request transmitted from the Web browser 11a (step S1).

  Next, the node processing unit 11c generates a content ID of the content based on the URL of the content included in the received request (Step S2). Here, the content ID is generated, for example, by hashing the content URL with the same hash function as that for generating the node ID. In this case, the hash value of the content URL is the content ID. The content ID may be configured such that a combination of content URL and content keyword information is hashed by the hash function. Since the content ID is generated based on the content URL as described above, it is not necessary to change the description of the Web page in order to describe the content ID of the content to be input to the overlay network ON1. That is, a content provider or the like may create a Web page on the assumption that content is distributed using a client-server distribution system. Therefore, specialized knowledge for publishing content on the overlay network ON1 is not required.

  The node processing unit 11c may be configured to acquire a content ID corresponding to the content URL from a predetermined server such as the management server MS. In this case, the node processing unit 11c transmits the URL of the content to a predetermined server. Then, the predetermined server generates a content ID based on the URL received from the node processing unit 11c and returns the content ID to the node processing unit 11c. Alternatively, the predetermined server acquires the content ID stored in association with the URL received from the node processing unit 11c and returns it to the node processing unit 11c. The node processing unit 11c may include the URL of the content metafile in the received request. In this case, the content ID of the content may be generated based on the URL of the content metafile.

  Next, as described above, the node processing unit 11c executes search processing for searching for the location of the content to be acquired based on the content ID generated in step S2 (step S3).

  Next, the node processing unit 11c determines whether or not the content to be acquired has been found from the overlay network ON1 by the search process in step S3 (step S4). For example, the node processing unit 11c can find the content to be acquired based on the index information transmitted from the root node in response to the content location inquiry message. When the node processing unit 11c has found the content to be acquired (step S4: YES), the node processing unit 11c proceeds to step S5. On the other hand, when the node processing unit 11c cannot find the content to be acquired (step S4: NO), the node processing unit 11c proceeds to step S10.

  In step S5, the node processing unit 11c acquires content from the content holding node indicated by the index information received from the root node by the search process. The content acquired in this way is buffered in the buffer memory 13.

  Next, the node processing unit 11c transfers the content acquired from the content holding node to the web browser 11a (step S6). Here, the Web browser 11a activates the player 11b corresponding to the player identifier described in the Web page. Then, the content transferred from the node processing unit 11c is reproduced by the player 11b. The node processing unit 11c and the web browser 11a may be configured with the same CPU. In this case, “transfer of the content from the node processing unit 11c to the Web browser 11a” is performed by the node processing unit 11c storing the content in a storage area of a RAM accessible to the Web browser 11a. Next, the node processing unit 11c determines whether or not acquisition of content from the content holding node has been completed (step S7). If the node processing unit 11c determines that the content acquisition has not been completed (step S7: NO), the node processing unit 11c returns to step S5. On the other hand, if the node processing unit 11c determines that the content acquisition has been completed (step S7: YES), the node processing unit 11c proceeds to step S8.

  In step S8, the node processing unit 11c stores the acquired content in the storage unit 12. Then, the node processing unit 11c performs publishing processing of the stored content (Step S9), and ends the processing illustrated in FIG. 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 11c generates a publish message. The publish message includes the content ID of the content and the node information of the node Nn that stores the content. Then, the node processing unit 11c 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 and the IP address of the node Nn in the storage unit 12 as index information.

  On the other hand, in step S10, the node processing unit 11c transfers the request received from the web browser 11a in step S1 to the web server WS. As a result, the content is distributed from the Web server WS. Then, the node processing unit 11c acquires content distributed from the Web server WS (step S11). Note that the processing in steps S12 and S13 is the same as the processing in steps S6 and S7. If the node processing unit 11c determines that the content acquisition has not been completed (step S13: NO), the node processing unit 11c returns to step S11. On the other hand, if the node processing unit 11c determines that the content acquisition has been completed (step S13: YES), the node processing unit 11c proceeds to step S14.

  By the way, as another example of the steps S10 and S11, the node processing unit 11c may be configured to acquire content from the node Nm constituting the overlay network ON2. In this case, the node Nn stores in advance the IP address and port number of the node Ni participating in the overlay network ON2, for example. The IP address and port number of any node Nm participating in the overlay network ON2 may be acquired from a predetermined server. Then, the node Nn accesses the node Ni according to, for example, the IP address and port number of the node Ni, and transmits a content request message. This content request message is a message for requesting content from the node Ni. The content request message includes, for example, the URL of the content included in the request received in step S1. Then, the node Ni generates the content ID of the content based on the URL included in the content request message. This content ID is generated, for example, by hashing the URL with a hash function common to the overlay network ON2. If the number system of content IDs is the same in the overlay network ON1 and the overlay network ON2, the content ID generated in step S2 may be included in the content request message. For example, when a common hash function is used in the overlay network ON1 and the overlay network ON2, the content ID numbering system is the same. Then, the node Ni performs a search process for searching for the location of the content based on the content ID. When the content is found from the overlay network ON2 by the search process, the node Ni acquires the content from the content holding node that stores the content. Then, the node Ni transmits the acquired content to the node Nn that transmitted the content request message.

  Next, in step S14, the node processing unit 11c determines whether or not the content acquired in step S11 satisfies the input condition for inputting to the overlay network ON1. Here, examples of the charging conditions include the following (a) to (f).

  (A) The content is acquired by the client-server method from the distribution device that stores the original content distributed by the overlay network ON1. The Web server WS that distributes content in step S11 corresponds to a distribution device that stores the original content distributed on the overlay network ON1. Therefore, in this case, the node processing unit 11c determines that the input condition is satisfied. Note that, as described above, content may be acquired from the node Nm participating in the overlay network ON2 in step S11. In this case, the node Nm corresponds to a distribution apparatus that stores the original content distributed by the overlay network ON1. By using the input condition (a), this content is input to the overlay network ON1 by the node Nn that first acquires the predetermined content from the Web server WS or the like. Therefore, it is possible to reduce time and effort for content providers and publishers to input content to the overlay network ON1 in advance.

  (B) The data size of the content is not less than a predetermined data size. In this case, the node processing unit 11c acquires information indicating the data size of the content acquired in step S11 from, for example, the operating system. The data size of content is also called a file size. Then, the node processing unit 11c determines whether or not the content data size is equal to or larger than a predetermined data size. The node processing unit 11c determines that the input condition is satisfied when the data size of the content is equal to or larger than a predetermined data size. Here, the “predetermined data size” is defined in advance by a node processing program, for example. By using the input condition (b), it is possible to input content having a data size equal to or larger than a predetermined size to the overlay network ON1. Therefore, for example, the processing load of the Web server WS can be reduced.

  (C) The current date is within the content publication period. In this case, the node processing unit 11 c acquires current date information indicating the current date from the clock function of the control unit 11. This current date may also include time. Furthermore, the node processing unit 11c acquires, from the Web server WS, for example, public period information indicating the public period of the content acquired in step S11. Then, the node processing unit 11c determines whether or not the current date is within the content publication period based on the current date information and the publication period information. The node processing unit 11c determines that the input condition is satisfied when the current date is within the content disclosure period. Here, the content publication period is a period during which the Web server WS can be distributed to the node Nn. In other words, the use of content is restricted within this publication period. By using the input condition (c), it is possible to input only contents within the public period to the overlay network ON1.

  (D) The predetermined period has not elapsed since the date when the content can be distributed. In this case, the node processing unit 11c acquires distributable information indicating the date on which the content acquired in step S11 can be distributed, for example, by the Web server WS, from the Web server WS, for example. This date may also include time. Then, the node processing unit 11c determines based on the distributable information whether a predetermined period has elapsed from the date when the distributable becomes possible. The node processing unit 11c determines that the input condition is satisfied when a predetermined period has not elapsed since the date when the distribution became possible. Here, the “predetermined period” is defined in advance by a node processing program, for example. By using the input condition (d), the recently released or updated content can be input to the overlay network ON1. For this reason, it can be expected that this content will be used in the overlay network ON1 for a long period after the input.

  (E) Content has been acquired from a distribution device registered in the distribution device list. In this case, the node processing unit 11c acquires the distribution device list from, for example, a system administrator's terminal (not shown). In this distribution device list, for example, distribution device information indicating distribution devices determined in advance by a system administrator is registered. As an example of the distribution apparatus determined in advance, there is a Web server that the system administrator wants to reduce the processing load on the CPU. Further, the distribution apparatus information includes, for example, the domain name and IP address of the distribution apparatus. Then, the node processing unit 11c determines, based on the distribution device information registered in the distribution device list, whether, for example, the Web server WS that has distributed the content acquired in step S11 is indicated in the distribution device information. The node processing unit 11c determines that the input condition is satisfied when, for example, the Web server WS is indicated in the distribution device information. By using the input condition (e), the processing load of, for example, the Web server WS registered in the distribution apparatus list can be reduced.

  (F) Content has been acquired from a distribution device whose content distribution speed is a predetermined speed or less. In this case, the node processing unit 11c measures the distribution speed of, for example, the Web server WS that has distributed the content acquired in step S11. For example, the bit rate (bps) of content from the Web server WS is measured as the distribution speed. Then, the node processing unit 11c determines, for example, whether the distribution speed of the Web page WS is equal to or lower than a predetermined distribution speed based on the measured distribution speed. For example, the node processing unit 11c determines that the input condition is satisfied when the distribution speed of the Web server WS is equal to or lower than a predetermined distribution speed. Here, the “predetermined delivery speed” is defined in advance by a node processing program, for example. By using the input condition (f), it is possible to reduce the processing load of the Web server WS, for example, whose delivery speed is as low as a predetermined speed or less.

  Note that any two or more combinations of the above (a) to (f) may be used as the input condition. For example, the node processing unit 11c determines that the input condition is satisfied when the data size of the content is equal to or larger than the predetermined data size and the predetermined period has not elapsed since the date when the distribution became possible. According to such a configuration, it is possible to further reduce the processing load of the Web server WS.

  If the node processing unit 11c determines in step S14 that the input condition is satisfied (step S14: YES), the process proceeds to step S15. On the other hand, when the node processing unit 11c determines that the input condition is not satisfied (step S14: NO), the process illustrated in FIG. 3 ends.

  In step S15, the node processing unit 11c stores the acquired content in the storage unit 12. Then, the node processing unit 11c performs publishing processing of the stored content (Step S16).

  Next, the node processing unit 11c executes input control for inputting the content acquired in step S11 to the overlay network ON1 (step S17), and ends the process illustrated in FIG. In this input control, first, the node processing unit 11c acquires the IP addresses and port numbers of a predetermined number of nodes Nn as content input destinations from the IP addresses and port numbers stored in the storage unit 12. For example, the IP address and port number of the node Nn that is the content input destination are acquired from the IP address and port number registered in the routing table using DHT and the index information. Further, history information of message transmission / reception performed by the node processing unit 11c with another node Nn via the overlay network ON1 may be stored in the storage unit 12. When the history information includes the IP address and port number of another node Nn, the IP address and port number of the node Nn that is the content input destination may be acquired from the history information. Then, the node processing unit 11c accesses the node Nn corresponding to each acquired IP address and port number, and transmits a content storage request message. This content storage request message is a message for requesting storage of content. The node Nn that has received the content storage request message returns a content storage permission message, for example, when there is an empty area for storing content in the storage unit 12 of the node Nn. This content input permission message is a message permitting storage of content. On the other hand, the node Nn that has received the content storage request message returns a content storage rejection message when there is no free space for storing the content in the storage unit 12 of the node Nn, for example. This content storage rejection message is a message for rejecting content storage. When the node processing unit 11c receives the content storage permission message, the node processing unit 11c transmits the content to the node Nn that has transmitted the content storage permission message.

  Thus, the node Nn that has received the content stores the content in the storage unit 12 and becomes a content holding node. Then, the content holding node that stores the content performs publishing processing of the content. The content input as described above is content that can be acquired by the overlay network ON1. In addition, you may comprise so that the process of said step S17 may be performed before the process of said step S15 and S16.

  As described above, according to the above-described embodiment, content not stored in the node Nn in the overlay network ON1 is input to the overlay network ON1 only when the input condition to input to the overlay network ON1 is satisfied. Therefore, even when the number of nodes Nn that store content in the overlay network ON1 is reduced, content distributed from distribution devices that do not belong to the overlay network ON1 is distributed and stored in the overlay network ON1 and content is efficiently stored. The distribution system S can be operated.

  In addition, after the content is input to the overlay network ON1, it is possible to reduce the processing load of a distribution device such as the Web server WS that distributes the content. Furthermore, a distribution device such as the Web server WS can be efficiently used as a content pool. Here, the content pool refers to a device that can always respond to a request for acquiring content in the overlay network ON1, for example. In the overlay network according to the conventional method, it is necessary to install a dedicated device as a content pool. However, in this embodiment, a distribution device such as the Web server WS can play the role. Therefore, in this embodiment, since it is not necessary to install a dedicated device as in the conventional method, the system can be made more efficient.

  Here, another example of the input control in step S17 will be described. In this case, in step S17, the node processing unit 11c transmits the URL of the content included in the request received in step S1 to the management server MS. When the management server MS receives the URL of the content transmitted from the node Nn, the management server MS acquires the content corresponding to the content URL from the Web server WS. That is, in this case, the management server MS includes a second acquisition unit that acquires content from the Web server WS based on the URL. Note that the management server MS may be configured to acquire content from the node Nm that constitutes the overlay network ON2, as in the method described in the other example of step S11. Then, the management server MS inputs the acquired content to the overlay network ON1. In other words, in this case, the management server MS includes an input unit that inputs the acquired content to the overlay network ON1. For example, the management server MS acquires the IP addresses and port numbers of a predetermined number of nodes Nn as content input destinations from the IP addresses and port numbers stored in the storage unit 12. Then, the management server MS accesses the node Nn corresponding to each acquired IP address and port number, and transmits a content storage request message. The subsequent operation is the same as when the node processing unit 11c transmits a content storage request message.

  In this way, the processing load on the node Nn can be reduced by the content input by the management server MS. Further, when the management server MS inputs content, the possibility that the power is turned off during the input is lower than that of the node Nn. Therefore, it is possible to input content to the overlay network ON1 more reliably than when the node Nn inputs.

  Further, when the management server MS inputs contents, the input contents can be collectively managed by the management server MS. For this reason, it is possible to avoid putting duplicate contents into the overlay network ON1.

  Further, when the node Nn is performing streaming playback while acquiring content from the Web server WS, special playback such as seek playback or skip playback may be performed according to a user instruction. In this case, the data portion of the content during a period such as seek playback or skip playback is not acquired by the node Nn. That is, the node Nn may not be able to acquire complete content from the web server WS. On the other hand, since special playback of content is not performed in the management server MS, complete content can be acquired from the Web server WS. Therefore, the management server MS can input complete content to the overlay network ON 1.

  Further, when the management server MS receives URLs of content from a plurality of nodes Nn at the same time, the management server MS can control the amount of content input according to the load status of the network NW and the node Nn.

  In the above-described embodiment, the node processing unit 11c may be configured to execute the input control for inputting the content to the overlay network ON1 without determining the input condition in step S14.

(4.2 Content deletion operation)
Next, the operation of deleting the content input to the overlay network ON1 by the process shown in FIG. 3 will be described. For example, it is desirable that content whose publication period has expired on the Web server WS or content that has been deleted by an operator's instruction is also deleted from the overlay network ON1. Examples of a method for deleting such content include the following methods (g) to (i).

(G) Method 1 for deleting content
In the case of this method 1, the content holding node stores date information indicating the date when the content is stored in the storage unit 12 in association with the content ID. This date may also include time. The content holding node periodically determines whether or not a predetermined period has elapsed from the date indicated by the stored date information. The predetermined period is set to about 5 days, for example. When the content holding node determines that the predetermined period has elapsed from the date indicated by the date information, the content holding node deletes the content corresponding to the content ID associated with the date information from the storage unit 12. According to the method 1, the content input to the overlay network ON1 by the process shown in FIG. 3 can be surely deleted later. In this method 1, even during the content publication period, everything may be deleted from the overlay network ON1. In this case, the node Nn that subsequently acquires this content is reintroduced into the overlay network ON1 in the process of step S17 shown in FIG.

(H) Method 2 for deleting content
In the case of Method 2, the content holding node transmits a message for inquiring whether or not the stored content can be acquired to the Web server WS every predetermined period. The predetermined period is set to about one day, for example. When the content holding node receives a message indicating that the content cannot be acquired from the Web server WS, the content holding node deletes the content from the storage unit 12. According to the method 2, the content input to the overlay network ON1 by the process shown in FIG. 3 can be deleted in accordance with the content publication period on the Web server WS, for example.

(I) Method 3 for deleting content
In the case of this method 3, each time the content root node receives a content location inquiry message transmitted from the user node, the reception date and time of this message is stored in the storage unit 12. Further, the content root node calculates a time interval between the reception date and time when the content location inquiry message is received and the reception date and time of the content location inquiry message received last time. Then, the root node of the content determines whether or not the calculated time interval is longer than a predetermined period. The predetermined period is set to about 7 days, for example. When it is determined that the calculated time interval is longer than the predetermined period, the content root node transmits a content deletion instruction message to all content holding nodes that store the content. This content deletion instruction message is a message for instructing the content holding node to delete the content. The content deletion instruction message includes the content ID of the content to be deleted. In this way, the content holding node that has received the content deletion instruction message deletes the content to be deleted from the storage unit 12. According to this method 3, for example, content that has become unpopular after being put into the overlay network ON1 can be surely deleted.

  By the way, in the methods (g) to (i) described above, when there are a plurality of contents to be deleted, the data size of each content is compared, and the contents with a small data size are preferentially deleted. Good. As a result, content with a large data size is acquired from the overlay network ON1, so that the processing load on the Web server WS can be reduced.

  In the above embodiment, the node Nn includes the web browser 11a, the player 11b, and the node processing unit 11c. As another example, one or more viewing terminals may be connected to the node Nn via, for example, a LAN (Local Area Network). In this case, the node processing unit 11c is provided in the node Nn. On the other hand, the viewing terminal includes a web browser 11a and a player 11b. That is, the node Nn functions as an edge server that acquires content in response to a request from the viewing terminal and provides the content to the viewing terminal. In other words, the node Nn functions as a proxy server that acquires content from the overlay network ON1 or the like instead of the viewing terminal. In this case, the function of the node processing unit 11c of the node Nn may be configured to be incorporated in a relay device such as a router.

  Moreover, in the said embodiment, although the peer to peer network using DHT was applied to the overlay network, it is not restricted to this. For example, a system using another 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.

DESCRIPTION OF SYMBOLS 1,11 Control part 2,12 Storage part 3,19 Communication part 13 Buffer memory WS Web server MS management server Nn, Nm node NW network ON1, ON2 Overlay network S Content delivery system

Claims (13)

In an overlay network composed of a plurality of information processing devices that can communicate with each other via a network, the information processing device is configured to acquire content from other information processing devices,
The information processing apparatus includes:
Search means for searching for the location of predetermined content stored in the information processing apparatus in the overlay network;
An acquisition unit that acquires the content from a distribution device that stores an original of the content distributed on the overlay network when the predetermined content cannot be found by the search unit;
A determination unit that determines whether or not the content acquired by the acquisition unit satisfies an input condition for input to the overlay network;
Control means for executing control to input the predetermined content into the overlay network as content obtainable by the overlay network when the determination means determines that the input condition is satisfied;
A distribution system comprising: The content stored in the information processing apparatus in the overlay network is given unique identification information for identifying the content in the overlay network,
The search means receives, from a web browser, a request including location information that is location information extracted from a web page transmitted from a web server and indicates the location of the predetermined content stored in the distribution device. Receiving means;
Generating means for generating identification information for identifying the predetermined content from content stored in an information processing apparatus in the overlay network based on the location information included in the received request;
With
The distribution system according to claim 1, wherein the search unit searches for the location of the predetermined content based on the generated identification information of the content. The distribution system includes a management server that manages the input of the content,
The control means transmits location information included in the received request to the management server,
The management server
Second acquisition means for acquiring the predetermined content from the distribution device based on the location information when the location information transmitted from the information processing device is received;
An input unit that inputs the predetermined content acquired by the second acquisition unit into the overlay network;
The distribution system according to claim 2, further comprising:   4. The distribution system according to claim 2, wherein the location information is a URI (Uniform Resource Identifier) of the predetermined content.   5. The determination unit according to claim 1, wherein the determination unit determines that the input condition is satisfied when the predetermined content is acquired from the distribution apparatus by a client-server method. 6. Distribution system. The information processing apparatus further includes third acquisition means for acquiring size information indicating a data size of the predetermined content,
Based on the size information acquired by the third acquisition unit, the determination unit determines that the input condition is satisfied when the data size of the predetermined content is equal to or larger than a predetermined data size. The delivery system according to any one of claims 1 to 4. The information processing apparatus includes: fourth acquisition means for acquiring current date information indicating a current date;
Fifth acquisition means for acquiring disclosure period information indicating a disclosure period of the predetermined content;
Further comprising
Based on the current date information acquired by the fourth acquisition unit and the publication period information acquired by the fifth acquisition unit, the determination unit determines that the current date is within the disclosure period of the predetermined content. 5, the distribution system according to claim 1, wherein the distribution system determines that the input condition is satisfied. The information processing apparatus further includes sixth acquisition means for acquiring distributable information indicating a date on which the predetermined content can be distributed by the distribution apparatus,
2. The determination unit, based on the distributable information acquired by the sixth acquisition unit, determines that the input condition is satisfied when a predetermined period has not elapsed since the date. 5. The distribution system according to any one of items 4 to 4. The information processing apparatus further includes seventh acquisition means for acquiring distribution device information indicating a predetermined distribution device,
Based on the distribution device information acquired by the seventh acquisition unit, the determination unit determines that the input condition is satisfied when the distribution device that has distributed the predetermined content is indicated in the distribution device information. The distribution system according to any one of claims 1 to 4, wherein: The information processing apparatus further includes a measurement unit that measures a distribution speed of the distribution apparatus,
The determination means, based on the distribution speed measured by the measurement means, determines that the input condition is satisfied when the distribution speed of the distribution device is equal to or lower than a predetermined distribution speed. Item 5. The distribution system according to any one of Items 1 to 4. The information processing apparatus included in a distribution system configured to acquire content from another information processing apparatus in an overlay network including a plurality of information processing apparatuses capable of communicating with each other via a network Because
The information processing apparatus includes:
Search means for searching for the location of predetermined content stored in the information processing apparatus in the overlay network;
An acquisition unit that acquires the content from a distribution device that stores an original of the content distributed on the overlay network when the predetermined content cannot be found by the search unit;
A determination unit that determines whether or not the content acquired by the acquisition unit satisfies an input condition for input to the overlay network;
Control means for executing control to input the predetermined content into the overlay network as content obtainable by the overlay network when the determination means determines that the input condition is satisfied;
An information processing apparatus comprising: In an overlay network composed of a plurality of information processing devices that can communicate with each other via a network, a computer included in a distribution system configured such that the information processing device acquires content from other information processing devices,
Searching for the location of the predetermined content stored in the information processing apparatus in the overlay network;
Acquiring the content from a distribution device that stores the original content distributed on the overlay network when the predetermined content cannot be found;
Determining whether the acquired content satisfies an input condition for input to the overlay network; and
If it is determined that the input condition is satisfied, executing the control to input the predetermined content to the overlay network as content that can be acquired by the overlay network;
Information processing program to execute. A content input method in a distribution system configured such that an information processing device acquires content from another information processing device in an overlay network composed of a plurality of information processing devices capable of communicating with each other via a network,
The content input method is:
The information processing device searching for the location of predetermined content stored in the information processing device in the overlay network;
Acquiring the content from a distribution device that stores an original of the content distributed on the overlay network when the information processing device fails to find the predetermined content;
The information processing apparatus determines whether or not the acquired content satisfies an input condition to input to the overlay network;
When the information processing apparatus determines that the input condition is satisfied, executing a control for inputting the predetermined content into the overlay network as content obtainable by the overlay network;
A content input method comprising:

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