JP2008033406A - NODE DEVICE, INFORMATION PROCESSING PROGRAM, CONTENT DISTRIBUTION METHOD, AND CONTENT DISTRIBUTION SYSTEM - Google Patents

Abstract

A burden on an apparatus for distributing content and a burden on a communication path of a network system are further reduced.
A plurality of first content data are distributed and stored in a plurality of node devices, and one node device communicates first content data stored by itself in response to a request from another node device. The node device 1 participating in the distributed content storage system S1 that is transmitted via the means, and the plurality of node devices 32 are connected in a tree shape via the communication means while forming a plurality of hierarchies. Distribution sources participating in the tree-type distribution system S2 in which the second content data distributed from the distribution-source node device 31 is sequentially transferred from the upper-level node device 32 to the lower-level node device 32. The first content data is acquired from the node device 1 and the acquired first content data is used as the second content data. To deliver to the node device 32.
[Selection] Figure 9

Description

  The present invention relates to a technical field such as a peer-to-peer (P2P) type content distribution system and method including a plurality of node devices connected to each other via communication means.

In recent years, with the spread of broadband, content distribution services such as VOD (video on demand) have been provided. A technology called peer-to-peer has attracted attention as a new form that replaces the server-client system, which is the mainstream form of current content distribution. As a peer-to-peer information communication system, a tree-type network format (for example, see Patent Document 1) is known.
JP 2006-33514 A

  As a tree-type content distribution service, a mode is conceivable in which a broadcast station device that first distributes content and plays the role of a broadcast station stores the content in a database of the device itself. Then, according to the program of the broadcast program, the broadcast station apparatus prepares the content to be distributed from the database and distributes it. At this time, if the content to be distributed increases, the database held by the broadcast station apparatus also increases. In addition to distributing content as a broadcast station, when transmitting content from the database to another node device, communication concentrates on the broadcast station device, and each communication may be delayed.

  Therefore, an object of the present invention is to provide a content distribution system and method that further reduce the burden on the content broadcasting station device and the burden on the communication path of the network system.

  In order to solve the above problem, the invention according to claim 1 is a distributed content storage system formed by participation of a plurality of node devices, wherein a plurality of first content data is distributed and stored in the plurality of node devices. And one of the node devices participates in a distributed content storage system in which the first content data stored by itself is transmitted via communication means in response to a request from the other node device. The node device, and a tree-type distribution system formed by participation of a plurality of node devices, wherein the plurality of node devices are connected in a tree shape via communication means while forming a plurality of hierarchies, The second content data distributed from the distribution source node device is sequentially transferred from the upper layer node device to the lower layer node device. A node device of the distribution source participating in the tree-type distribution system, wherein the first content data is acquired from the node device storing the first content data in the distributed content storage system; A node comprising: content data acquisition means; and second content data distribution means for distributing the acquired first content data as the second content data to the other node devices in the tree-type distribution system. Device.

  According to this, since the distribution source node device does not need to store the second content data to be distributed in advance in a database or the like, a large amount of content data is stored in the database in advance, and communication concentrates on the node device. Is prevented. Therefore, the burden on the node device itself and the communication path, that is, the burden on the entire content distribution system is reduced. Further, the distribution source node device functioning in this manner does not need to increase the second content data storage database to be distributed, and can prevent the distribution content database from being expensive. Furthermore, if the distribution source node device has such a configuration, a normal node device can function as a broadcast station device without separately providing a broadcast station device in the tree-type distribution system.

  In order to solve the above-mentioned problem, the invention according to claim 2 is the node device according to claim 1, wherein the first content data acquisition means transmits the first content data transmitted by a streaming method. The second content data distribution means is a node device that distributes the second content data to the other node devices in a streaming manner.

  According to this, by performing transmission / reception of data by the streaming method, the node device can transmit the second content data corresponding to the first content data even while the first content data is being received. it can. Therefore, the second content data can be transmitted in the tree-type distribution system without waiting until all the data is received, and the data can be quickly distributed.

  In order to solve the above-described problem, the invention according to claim 3 is the node device according to claim 1 or 2, wherein the node device further stores the received first content data. A node device characterized by comprising:

  According to this, since the node device can store the first content data, when the second content data corresponding to the same first content data is distributed again, it is necessary to start by acquiring the first content data again. In addition, the burden on the communication path can be reduced.

  In order to solve the above-described problem, the invention according to claim 4 is the node device according to claim 3, wherein the node device further acquires the first content data when the first content data is acquired. A storage determining unit configured to determine whether or not the content data is stored in the recording medium, and the recording medium newly stores the first content data when the storage determining unit determines that the content data is stored; Is a node device characterized by

  According to this, the node device can determine whether or not to newly record the first content data according to the necessity of the first content data, the remaining storage capacity of the recording medium of the node device, and the like. Therefore, the received first content data can be stored as necessary without imposing a burden on the node device.

  In order to solve the above problem, the invention according to claim 5 is the node device according to claim 3 or 4, wherein the node device further adds the first content data to the recording medium. When stored, the public information indicating that the first content data is stored in the other node device is directed to the node device that manages the location of the first content data in the distributed content storage system. Public information transmitting means for transmitting, request receiving means for receiving transmission request information for requesting transmission of the first content data from another node device, and the request receiving means from the other node device for the transmission request When the information is received, the first content data for transmitting the first content data stored in the recording medium according to the transmission request information. A transmission unit, a node device, characterized in that it comprises a.

  According to this, by disclosing to the other node device that the distribution source node device stores the first content data, the other node device receives the first content from the distribution source node device. Data can be acquired. Therefore, in addition to the node device (for example, the content node) that originally stored the first content node, the other node device can acquire the first content data from the distribution source node device. In addition to improving the convenience of the user, the burden of communication for transmitting the first content data to the other node device in the node device that originally stored the first content node is reduced.

  In order to solve the above problem, the invention according to claim 6 is the node device according to claim 5, wherein the node device further stores the first content data in the recording medium. The public information transmission means for determining whether or not to transmit the public information, and the public information transmission means transmits the public information when the public determination means determines to transmit the public information. It is a node device characterized by doing.

  According to this, the node device can determine whether or not to transmit the public information according to the necessity of copying the first content data in the content distributed storage system, the communication status of the node device, and the like. For this reason, when it is determined that the public information is not transmitted, the transmission request information is not received from another node device, so that it is possible to prevent an increase in communication burden on the node device.

  In order to solve the above problem, the invention according to claim 7 is the node device according to any one of claims 1 to 6, wherein the node device further includes the second content data distribution unit. The search information for searching the location of the node device storing the first content data corresponding to the second content data to be distributed by managing the location of the first content data in the distributed content storage system When receiving node information indicating the location of the first content data from the management source node device and the search means for transmitting to the management source node device, the node device corresponding to the node information Request transmission means for transmitting transmission request information for requesting transmission of the first content data, and the first content data acquisition means Is a node device and acquires the first content data from the node device of the destination of the transmission request information.

  According to this, when the node device transmits the search information, the location of the first content data (such as the IP address of another node device storing the first content data) can be known, and from the other node device The first content data can be acquired. Therefore, it is not necessary for the node device to always store the location of the first content data, and the burden of storing in the node device is reduced.

  In order to solve the above-described problem, an invention according to claim 8 is the node device according to any one of claims 1 to 7, wherein the node device further acquires the acquired first content data. Is converted into a format for distribution in a tree-type distribution system and converted into the second content data, and the second content data distribution unit converts the second content after being converted by the conversion unit. A node device that distributes data to the other node devices.

  According to this, the node device can distribute the second content data in a format suitable for the tree distribution system by converting the data, and the downstream node device is burdened by the lack of the data format. Is prevented.

  In order to solve the above-described problem, the invention according to claim 9 is the node device according to claim 8, wherein the conversion means is at least one of video, image, and audio included in the first content data. The node device is characterized in that the second content data is deteriorated.

  According to this, the node device is converted in the tree-type distribution system and distributes the second content data having a lower quality than the regular first content data, and the regular first content is distributed in the content distributed storage system. Data can be saved. Then, a viewer who likes viewing the second content data in each node device of the tree-type distribution system can acquire the regular first content data again in the content distributed storage system.

  In order to solve the above problem, the invention according to claim 10 is the node device according to claim 8 or 9, wherein the conversion means partially thins out the video included in the first content data. Selecting a part of the video included in the first content data; reducing the size of the video or image included in the first content data; degrading the image quality of the video or image included in the first content data; And a node device that performs at least one of the following: degrading the sound quality of the sound included in the first content data.

  According to this, in addition to the above points, the first content data is specifically converted and distributed as second content data, thereby reducing the capacity of data transmitted and received by the downstream node device. It is also possible to reduce the burden on the node device.

  In order to solve the above-mentioned problem, the invention according to claim 11 is the node device according to any one of claims 1 to 10, wherein the first content data acquired by the first content data acquisition means. Further includes content determination means for determining whether or not it corresponds to content data distributed in the tree-type distribution system, and the first content data acquired by the content determination means by the first content data acquisition means is the tree. When it is determined that it corresponds to content data to be distributed in the type distribution system, the second content data distribution unit uses the acquired first content data as the second content data as another node device in the tree type distribution system. The node device is characterized in that it is distributed to the network.

  According to this, when a normal node device functions as a node device that is a distribution source of the tree-type distribution system, the content determination unit determines that the acquired first content data is based on the desire of the node device (user). It is possible to determine whether it has been acquired or acquired for distribution in the tree-type distribution system. At this time, the node device can distribute only the content data acquired for distribution in the tree distribution system as the second content data.

  In order to solve the above problem, an invention according to claim 12 is an information processing program that causes a computer to function as the node device according to any one of claims 1 to 11.

  In order to solve the above problem, the invention according to claim 13 is a content distributed storage system formed by participation of a plurality of node devices, wherein a plurality of first content data is distributed and stored in a plurality of the node devices. One node device participates in a distributed content storage system that transmits the first content data stored by itself in response to a request from the other node device via a communication means. The node device, and a tree-type distribution system formed by participation of a plurality of node devices, wherein the plurality of node devices are connected in a tree shape via communication means while forming a plurality of hierarchies, The second content data distributed from the distribution source node device is sequentially transferred from the upper layer node device to the lower layer node device. The content distribution method in the distribution source node device participating in the tree-type distribution system, wherein the first content data from the node device storing the first content data in the content distributed storage system And a step of distributing the acquired first content data as the second content data to the other node devices in the tree distribution system.

  In order to solve the above problem, the invention according to claim 14 is a content distributed storage system formed by participation of a plurality of node devices, wherein a plurality of first content data are distributed and stored in the plurality of node devices. A distributed content storage system in which one of the node devices transmits the first content data stored in response to a request from the other node device via a communication unit; and A tree-type distribution system formed by participation of node devices, wherein the plurality of node devices are connected in a tree shape via communication means while forming a plurality of hierarchies, and distributed from a distribution-source node device. (2) A tree-type distribution system in which content data is sequentially transferred from the node device in the upper layer to the node device in the lower layer. The node device participating in the content distributed storage system and the distribution source node device participating in the tree type distribution system in the content distributed storage system In the tree distribution system, a first content data acquisition unit that acquires the first content data from the node device that stores the first content data, and the acquired first content data as the second content data. And a second content data distribution means for distributing to the other node device.

  According to the present invention, the distribution source node device has the first content data receiving unit and the second content data transmission unit in particular, so that the load on the node device itself and the communication path, that is, the load on the entire content distribution system. Is reduced.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the best embodiment of the invention will be described with reference to the drawings. The embodiment described below is an embodiment when the present invention is applied to a content distribution system including a distributed content storage system and a tree-type distribution system using DHT. In the present invention, the content data transmitted / received in the content distributed storage system is the first content data, and the content data transmitted / received in the tree type distribution system is the second content data. Each of the inventions such as the content distribution system of the present invention is not limited to the embodiments described below, and can be implemented with appropriate modifications within the scope of the technical idea of the present invention.

[1. Outline of content distribution system]
First, a schematic configuration and the like of the content distribution system S will be described with reference to FIG.

  FIG. 1 is a diagram illustrating an example of a connection mode of each node device in the content distribution system S according to the present embodiment.

  As shown in the lower frame 101 of FIG. 1, IX (Internet eXchange) 3, ISP (Internet Service Provider) 4, DSL (Digital Subscriber Line) line operator (device) 5, FTTH (Fiber To The Home) line A network (real-world network) 8 such as the Internet is constructed by a business operator (device) 6 and a communication line (for example, a telephone line or an optical cable) 7.

  The content distribution system S is configured to include a plurality of node devices 1a, 1b, 1c,... 1x, 1y, 1z,. Network system. Each node device 1a, 1b, 1c... 1x, 1y, 1z... Is assigned a unique manufacturing number and IP (Internet Protocol) address as information indicating the node device. The production number and the IP address are not duplicated among the plurality of node devices 1. In the following description, when any one of the node devices 1a, 1b, 1c... 1x, 1y, 1z.

[2. Configuration of distributed content storage system]
Next, the configuration and the like of the content distributed storage system S1 included in the content distribution system S will be described.

[2.1. Outline of DHT]
Hereinafter, an algorithm using a distributed hash table (hereinafter referred to as DHT (Distributed Hash Table)) according to the content distributed storage system S1 of the present embodiment will be described.

  In the content distribution system S described above, when the node devices 1 exchange information with each other, they must know the IP address as the node information of each other.

  For example, in a system for sharing content with each other, it is a simple technique for each node device 1 participating in the network 8 to know the IP addresses of all the node devices 1 participating in the network 8. However, when the number of terminals becomes as large as tens of thousands and hundreds of thousands, it is not realistic to remember the IP addresses of all the node devices 1. When the power of any node device is turned on or off, the IP address of the arbitrary node device stored in each node device 1 is frequently updated, which makes operation difficult.

  Therefore, in one node device 1, only the minimum necessary IP address of the node device 1 among all the node devices 1 participating in the network 8 is remembered (stored), and the IP address is set. For node devices 1 that are not known (not stored), a system has been devised in which information is transferred between the node devices 1 and sent to each other.

  As an example of such a system, an overlay network 9 as shown in the upper frame 100 of FIG. 1 is constructed by an algorithm using DHT. That is, the overlay network 9 means a network that forms a virtual link formed by using the existing network 8.

  In the present embodiment, an overlay network 9 constructed by an algorithm using DHT is premised, and the node device 1 arranged on the overlay network 9 participates in the content distributed storage system S1 (in other words, the overlay network 9). The node device 1 participating in 9). Note that the participation in the content distribution storage system S1 is performed by a node device that has not yet participated sending a participation request to an arbitrary node device 1 that has already participated.

  The node ID of each node device 1 participating in the content distributed storage system S1 is assigned a unique (unique) number for each node device. This number needs to have a number of bits that can accommodate the maximum number of operating node devices. For example, if a 128-bit number is used, 2 ^ 128 = 340 × 10 ^ 36 node devices can be operated.

  More specifically, the node ID of each node device 1 is obtained by hashing a unique value for each node device such as the IP address or manufacturing number of each node device using a common hash function (hash algorithm). It is a hash value and is distributed and distributed in one ID space without any deviation. Thus, the node ID obtained (hashed) by the common hash function has a very low probability of having the same value if the IP address or the manufacturing number is different. Since the hash function is publicly known, detailed description thereof is omitted. In the present embodiment, a node ID is a value obtained by hashing an IP address (global IP address) with a common hash function.

  The plurality of node devices 1 participating in the distributed content storage system S1 have first content data (for example, data such as movies and music) distributed from one node device 1 to another node device 1. Although stored (saved) in a distributed manner, a unique number (hereinafter referred to as a content ID) is assigned to the first content data for each content data.

  The content ID has the same length as the node ID (for example, 128 bits). For example, when a keyword such as a content name (content title) or content outline information (synopsis) obtains the node ID. And the node ID that is hashed by a common hash function (that is, placed in the same ID space as the hash value of the IP address of the node device 1) and closest to the hash value (for example, the higher-order digits match more). The node device 1 having the information stores (saves) the first content data or holds link information (IP address of the content holding node) to the node device that holds the content data. As a result, the first content data can be distributed on the content distributed storage system S1 without any bias. In addition, even if it is different 1st content data, the case where it becomes the same keyword (for example, name of content) is assumed, but since it will become the same hash value in this case, in order to avoid this, hash The keyword to be converted may be, for example, a combination of a content name and copyright information (for example, performer name, director name, original author name, singer name, composer name, or songwriter name).

  Thus, since the node ID and content ID assigned to each node device 1 and each first content data are generated by a common hash function, as shown in FIG. It can be thought of as being scattered and present. This figure shows a node ID and content ID assigned in 32 bits. In the figure, a black dot indicates a node ID, a black diamond indicates a content ID, and the ID increases counterclockwise.

  Next, which node device 1 stores which first content data is stored is determined under a certain rule. In the present embodiment, the rule is that “a node device that manages content data having a certain content ID is a node device 1 having a node ID close to that content ID”. Here, the definition of “close” does not exceed the content ID and the difference between the content ID and the node ID is the smallest. In practice, each node device manages each first content data. It is only necessary to be consistent when allocating to 1. In the example shown in the figure, based on this definition, the content IDa is managed by the node device 1 having the node IDa, the content IDb is managed by the node device 1 having the node IDb, and the content IDc is the node IDc. It is managed by the node device 1 having it.

  Here, “management” does not mean that the first content data is stored (held), but “knows in which node device 1 the first content data is stored. Say. That is, in FIG. 2, the node device 1 having the node IDa knows in which node device 1 the first content data having the content IDa is stored, and the node device 1 and the node IDc having the node IDb are stored. Similarly, the node device 1 having the same knows in which node device 1 the first content data having the content IDb and the first content data having the content IDc are stored. Thus, a node device that knows in which node device 1 certain first content data is stored is called a root node of the first content data. That is, the node device 1 having the node IDa is the root node of the first content data having the content IDa, and the node device 1 having the node IDb is the root node of the first content data having the content IDb, The node device 1 having the node IDc is the root node of the first content data having the content IDc. The node device 1 that holds (stores) the first content data is referred to as a content node.

[2.2. Create routing table]
Here, an example of a method for creating a routing table used in DHT will be described with reference to FIG.

  FIG. 3 is a diagram illustrating an example of how a routing table is created by DHT.

  First, as shown in FIG. 3A, the ID space is divided into several areas. Actually, about 16 divisions are often used, but in order to simplify the explanation, here, four divisions are used, and ID is represented by a quaternary number having a bit length of 16 bits. An example in which the node device 1N has a node ID “10230210” and creates a routing table for the node device 1N will be described.

(Level 1 routing)
First, if the ID space is divided into four, each area is represented by four areas with different maximum digits “0XXXXXXX”, “1XXXXXXX”, “2XXXXXXX”, “3XXXXXXX” (where X is a natural number from 0 to 3, The same). Since the node ID of the node device 1N itself is “10230210”, the node device 1N exists in the area “1XXXXXXX” in the lower left in the figure. Then, the node device 1N appropriately selects the node device 1 existing in an area other than the area where the node device exists (that is, the “1XXXXXXX” area), and stores the IP address of the node ID in the level 1 table. . FIG. 4A shows an example of a level 1 table. Since the second column indicates the node device 1N itself, it is not necessary to store the IP address.

(Level 2 routing)
Next, as shown in FIG. 3B, among the areas divided into four by the above routing, the area where the user exists is further divided into four, and four areas “10XXXXXX”, “11XXXXXX”, “12XXXXXX”, “13XXXXXX” ". Then, similarly to the above, the node device 1 existing in an area other than the area in which it exists is appropriately selected, and the IP address of the node ID is stored in the level 2 table. FIG. 4B is an example of a level 2 table. Since the first column indicates the node device 1N itself, it is not necessary to store the IP address.

(Level 3 routing)
Further, as shown in FIG. 3C, among the areas divided into four by the above routing, the area where the user exists is further divided into four, and further four areas “100XXXXX”, “101XXXXX”, “102XXXXX”, “103XXXXX” And divide. Then, similarly to the above, the node device 1 existing in an area other than the area where it exists is appropriately selected, and the IP address of the node ID is stored in the level 1 table. FIG. 4C is an example of a level 3 table. Since the third column shows the node device 1N itself, it is not necessary to store the IP address, and the second column and the fourth column are blank because there is no node device in the area.

  In this way, all the 16-bit IDs can be covered by creating the routing table as shown in FIG. As the level goes up, white space becomes more noticeable in the table.

  All the node devices 1 each create and own the routing table created according to the method described above.

[2.3. First Content Data Search Method and Acquisition Method]
Next, an example of a search method and an acquisition method of the node device 1 that is the storage source of the first content data will be described with reference to FIG. This is performed by a first content data acquisition unit, a search unit, a request transmission unit, a request reception unit, and a first content data transmission unit in the node device 1 to be described later.

  FIG. 5 is a diagram illustrating an example of a state where the node device 1 storing the first content data is searched by DHT and a state where the first content data is acquired.

  Here, the node device 1-1 having the node ID “12003030” (hereinafter, the node device that searches for the first content data and requests reception of the first content data is referred to as “request node”). A procedure for searching for the first content data having the ID “31330012” will be described.

  The request node refers to the level 1 table of the routing table held by itself, and retrieves search information (hereinafter, referred to as the location of the content) to the node device having the node ID in the same area as the content ID “31330012”. “Search information” (search information for searching a node device storing desired first content data) of the present invention is referred to as “query”). That is, since the content ID “31330012” is the area of “3XXXXXXX”, the node device 1 belonging to the area of “3XXXXXXX” knows the IP address (that is, the IP address is stored in the routing table held by itself). A query is transmitted to the node device 1-2 in which the address is stored. Thus, the query includes a content ID that is unique identification information corresponding to the content.

  According to the example shown in FIG. 5, since the IP address of the node device 1-2 with the node ID “30100000” is stored in the routing table of the request node, the request node has the node ID “30100000”. A query is transmitted to the node device 1-2.

  Next, the node device 1-2 that has received the query refers to the level 2 table of the routing table held by the node device 1-2 itself, and the node device 1-2 belongs to the area “31XXXXXX”. The query is transferred to the node device 1-3 (node ID “31012001”) that knows the IP address.

  In this way, the transfer of the query proceeds in such a manner that the digits of the content ID are adapted in order from the top, and finally the node device 1-5 that manages the first content data, that is, the root node (content distribution in the present invention) When it arrives at the node device of the management source that manages the location of the first content data in the storage system, the root node has the content index “31330012” included in the query managed by itself. Information is searched from information (described later), and node information such as the IP address of the node device 1 that owns the first content data is returned to the request node.

  Thus, the request node (node device 1-1) receives the location of the first content data with the content ID “31330012” from the root node (node device 1-5), that is, the content node storing the data ( The node device 1-6) receives the IP address and knows it. The request node transmits transmission request information requesting transmission of the first content data to the content node searched in this way, and acquires (downloads) the first content data from the content node. .

  In addition, when the content node receives transmission request information requesting transmission of the first content data from the request node and receives transmission request information from the request node, the content node transmits the first content data according to the transmission request information. To do.

  Although not shown, the root node that has received the query transmitted by the request node instructs the content node that stores the corresponding first content data to distribute the first content data to the request node. Information may be sent. In this case, the content node can acquire desired first content data from the content node without transmitting the transmission request information.

[2.4. Method for publishing first content data]
In the content distributed storage system S1 having such a configuration, for example, a certain node device (referred to as the node device 1-6 described above) sends new first content data to another node device 1 on the content distributed storage system S1. A method for publishing so that the location can be understood will be described with reference to FIG. This is performed by public information transmitting means in the node device 1 described later. This node device 1-6 becomes a content node for storing the first content data.

  As shown in FIG. 6, first, new first content data is input to the node device 1-6 from the content input server 26 that manages the type and number of the first content data input to the content distributed storage system S1. Is done.

  The node device 1-6 that has become the content node in this manner obtains the content ID; 31330012 from the content title or the like, toward the node device having the same node ID as the content ID (whether or not this node device actually exists). This is not known at this point.) Public information indicating that the own node device stores the first content data (hereinafter, the public information of the present invention is referred to as a content public message) is transmitted. Then, this content disclosure message is also transferred one after another according to the routing table in the same manner as the above query, and when it is transferred to the node device 1 having the node ID closest to the content ID included in the content disclosure message, When the node device 1 determines that there is no other destination node device, the node device 1 determines that the node device 1 itself should be the root node of the first content data, and the content ID, auxiliary information (title, genre) Etc., copyright information such as a director name) and the IP address of the content node are stored as content index information.

  Note that the number of content nodes is not limited to one, and there may be another node device 1 (hereinafter also referred to as a replica node) that stores the same first content data and makes it public. Also in this case, when the second and subsequent replica nodes transmit the public message in the same manner, the same root node manages the location of the first content data.

  Furthermore, the node device in the middle of the route to the root node may hold the content index information stored in the root node as a cache. A node device that holds the content index information as a cache is called a cache node. This enables the cache node to return the IP address of the content node to the request node that inquired about the location of the content when the query is transferred to the cache node sooner before the root node receives the query. become. It should be noted that the number of cache nodes, whether or not all of the node devices 1 to which the public message is transferred are set as cache nodes, and the like can be freely determined in the content distributed storage system S1.

  In addition, when the first content data stored in the content node is deleted by an instruction from the content input server 26, the content deletion message is transmitted in the same manner and transferred to the root node one after another. The root node or cache node that has received the message deletes various information of the node device 1 that has transmitted the content deletion message from the content nodes of the first content data from the content index information.

[2.5. How to participate in a distributed content storage system]
Next, a method of participating in the distributed content storage system S1 of the node device will be described with reference to FIG.

  As shown in FIG. 7, the content distributed storage system S1 includes a contact node introduction server 25. As shown in the lower frame 101 of FIG. 1, when a node device 1 communicating with another node device 1 via a network participates in the distributed content storage system S1, first, the contact node introduction server 25 is used. A contact node introduction request message is transmitted. Upon receiving the contact node introduction request message, the contact node introduction server 25 first receives an IP address of a node device (hereinafter referred to as a contact node) with which the node device 1 (hereinafter referred to as a participating node) participating in the system S1 will first communicate. The contact node information such as is returned to the participating node.

  Next, the participating node transmits a participation message to the contact node based on the received contact node information, and the contact node that has received the participation message sends the participation message to the first level of the routing table (see FIG. 4D). The table information in which the node ID of the level 1 level) and the IP address are associated with each other is transmitted.

  Next, the contact node obtains a node ID (corresponding to the white circle in the upper right in FIG. 7) obtained from the IP address of the participating node, and sends a participation message to the node device 1 having the node ID closest to the content ID. Forward. Information indicating that the next stage (second stage) table information of the stage (first stage) table information transmitted by the contact node should be transmitted to the participating node is added to the participation message. This participation message is also transferred one after another according to the routing table in the same manner as the above query, and the transfer is stopped when it is transferred to the node device 1 having the node ID closest to the node ID included in the participation message. It is done.

  In addition, each node device 1 that has received the transferred participation message sends a predetermined level of table information (level 2 and subsequent levels in FIG. 4D) to the participating node in accordance with the instructions included in the participation message. Send. When transferring this participation message, the table information of the next level (for example, the third level) of the table information (for example, the second level) transmitted by the node device 1 should be transmitted to the participating node. Add information to that effect.

  Thus, the participating node can receive the table information of each level of the routing table from each node device that has received the participation message, and can create and store the routing table.

[3. Configuration of tree-type distribution system]
Next, the configuration and the like of the tree distribution system S2 included in the content distribution system S according to the present embodiment will be described with reference to FIG.

  FIG. 8 is an explanatory diagram illustrating an example of a connection mode of each device in the tree distribution system S2 according to the present embodiment. In the example of FIG. 8, a communication connection mode between devices in the tree-type distribution system S2 (for example, a connection relationship between which device and which device has established communication) is shown. In the present embodiment, the second content data (hereinafter also referred to as “broadcast content data”) distributed from the broadcast station device (representing the node device of the distribution source in the present invention) 31 is a buffer memory provided in the node device 32a. The second content data is reproduced while being temporarily stored. In addition, the second content data is transmitted to another node device 32c or the like while temporarily storing the second content data in a buffer memory provided in the node device 32a. The distribution of the second content data in the broadcast station apparatus 31 is performed by the second content data distribution means.

  As shown in FIG. 8, the tree-type distribution system S2 includes a broadcast station apparatus 31 that is a distribution source of second content data such as streaming data, and a plurality of nodes that receive content distributed from the broadcast station apparatus 31. .., 32m, and is a peer-to-peer (P2P) type network system.

  In addition, the tree-type distribution system S2 has a plurality of communication paths 33a, 33b, 33c,... Based on each IP address while a plurality of node devices 32a to 32m form a plurality of hierarchies with the broadcasting station device 31 as the highest level. ..., connected in a tree shape through 33m.

  Then, the second content data distributed by the broadcasting station device 31 is sequentially transferred from the upper layer node devices 32a and 32b to the lower layer node devices 32c to 32m. In the following description, when any one of the node devices 32a to 32m is shown, it may be called the node device 32 for convenience.

  Note that the distribution server 1 and the plurality of node devices 32a to 32m are similar to the description of the content distribution system S with reference to FIG. 1, such as IX (Internet eXchange) 3, ISP (Internet Service Provider) 4, DSL. (Digital Subscriber Line) network operator (device) 5, FTTH (Fiber To The Home) line operator (device) 6, communication line (eg, telephone line, optical cable, etc.) 7, etc. As described above, a unique node ID and IP address are allocated to the broadcasting station device 31 and each of the node devices 32a to 32m.

  Further, the connection destination introduction server 35 stores the device information of the node device connected to the highest layer for each provider information indicating which network connection service provider the node device 32 is connected to the network. is doing. Therefore, for example, when a new node device 32i desires to participate in the tree-type distribution system S2, that is, when it desires to distribute the second content data distributed by the broadcasting station device 31, it is connected to itself. In order to be informed of the node device 32 that is a candidate for the upper layer node device 32 to be transmitted, a connection destination candidate request Sc is transmitted to the connection destination introduction server 35 as shown by a one-dot chain line in the figure. Then, based on the provider information indicating the network connection service provider to which the node device 32 is connected, the connection destination introduction server 35 selects another node device as the upper layer node device 32 to which the node device 32 should be connected. 32d is selected, and the device information (including the IP address) of the node device 32d is transmitted as a connection destination candidate notification to the node device 32 as indicated by a two-dot chain line in the figure.

  Based on the device information included in the connection destination candidate notification (Nk {}), the node device 32i transmits to the upper layer node device 32 (the node device 32d in the example shown in FIG. 8) to be connected. On the other hand, as shown by the dotted line in the figure, the connection request information Sr including its own device information is transmitted to make a connection request, and the node device 32d that receives this requests should transfer the second content data to the node device 32i. If it is determined, the connection between the node device 32i and the node device 32d via the communication path 33i can be established.

[4. Overview of Content Distribution System of this Embodiment]
Next, an outline and the like of the content distribution system S according to the present embodiment will be described with reference to FIGS. 9 to 11. As shown in FIG. 9, the content distribution system S of the present embodiment includes a content distribution storage system S1 and a tree distribution system S2, and in addition to the node devices 1 and 32 participating in each, the content distribution storage system S1 A contact node introduction server 25, a connection destination introduction server 35 of the tree distribution system S2, and a content input server 26 operating in both systems S1 and S2.

  In the content distribution system S including the content distributed storage system S1 and the tree type distribution system S2, the node device 1 functions as the broadcasting station device 31 in the tree type distribution system S2, and the first content in the content distributed storage system S1. The first content data is acquired from the node device 1 (content node) storing the data, and the acquired first content data is distributed as the second content data to the other node devices 32 in the tree type distribution system S2. It is a feature. This is performed by a first content data acquisition unit and a second content data distribution unit in the node device 1 to be described later.

  Therefore, the node device 1 functioning as a broadcasting station does not need to always store each second content data to be distributed, acquires the first content data corresponding to the second content data at a necessary timing, and is unnecessary. If there is, it can be deleted after delivery. Therefore, the node device 1 does not need to prepare a recording medium with a large capacity for storing the second content data, and functions as the broadcasting station device 31 even in the normal node device 1 as described above. It becomes possible.

  When the node device 1 obtains the desired first content data, it will be described with reference to FIG. 5, and as shown in FIG. 9, the node device 1 is the content corresponding to the desired first content data. A query is transmitted toward the node device 1 (root node) having the node ID closest to the ID. When the query is transferred and received by the root node of the first content data, the root node transmits the location information (IP address or the like) of the content node storing the first content data to the node device 1. When the node device 1 knows the location of the content node, the node device 1 transmits transmission request information for requesting the content to the content node. The content node that has received the transmission request information transmits the first content data to the node device 1.

  The node device 1 that has received the first content data from the content node will be described with reference to FIG. 8, and as shown in FIG. 9, the first content data is used as the second content data in the tree distribution system S2. It is distributed to the other node devices 32a and 32b. The node devices 32a and 32b reproduce the second content data, and the second content data received by the downstream node devices 32c, 32d, 32e, and 32f according to the distribution destination (topology) determined in the tree. Transfer each one. Each node device 32 that has received the second content data operates in the same manner, and the node devices 32g, 32h, 32i, 32j, 32k, 32l, and 32m that are the most downstream and have no transmission destination reproduce the second content data. , Erase data without transferring as it is.

  At this time, the node device 1 can acquire the first content data transmitted by the streaming method, and can distribute the second content data to the other node devices 32 by the streaming method. In this case, the node device 1 can transmit the second content data corresponding to the first content data from the portion that has received the first content data even while the first content data is being received. Therefore, the second content data can be transmitted in the tree-type distribution system without waiting until all the data is received, and the second content data can be quickly distributed.

  As shown in FIG. 10, the broadcast station apparatus 31 includes a broadcast program file (see FIG. 10A) that lists which second content data is broadcast in what order at what time, as a content input server. 26 (see FIG. 10B). In this embodiment, the broadcast program file is a list of broadcast time, content ID of the second content data for which the broadcast order is determined, and acquisition timing of the second content data.

  In accordance with this broadcast program file, the broadcast station apparatus 31 sends the corresponding first content data to the content distributed storage system S1 at the designated 7:50 for the second content data of the content ID: 10000001 that starts broadcasting at 8:00. A query for acquisition is transmitted, and the first content data is acquired. Subsequently, for the second content data of the content ID: 10000002 to be broadcast next, a query for acquiring the corresponding first content data in the content distributed storage system S1 is transmitted to acquire the first content data. Furthermore, for the second content data with the content ID 10001000 to be broadcast next, when the second content data with the first content ID 10001000 is broadcast, the corresponding first content data is transferred to the content distributed storage system S1. A query for acquisition is transmitted, and the first content data is acquired. In this way, the broadcast station apparatus 31 can sequentially acquire the first content data corresponding to the second content data to be broadcast in the content distributed storage system S1, and delete unnecessary ones after the broadcast.

  On the other hand, the broadcast station apparatus 31 starts broadcasting the content whose broadcast time is determined as the second content data using the first content data of the acquired content ID: 10000001 when the broadcast time is 8:00. If the order is determined like the second content data with ID: 10000001 and the second content data with content ID: 10000002, the first content data with the acquired content ID: 10000002 is obtained at that timing. Broadcasting is started as second content data.

  In addition, although the acquisition timing of each 2nd content data was shown in the broadcast program file shown to FIG. 10 (A), the acquisition timing is not shown in the broadcast program file, and the node apparatus used as the broadcast station apparatus 31 1, the acquisition timing may be set in time for the content distribution time.

(Storage and release of the acquired first content data)
The broadcast station apparatus 31 can delete the acquired first content data, but can also store it in a recording medium. It can also be determined whether or not the first content data acquired by the storage determination unit is stored in the recording medium. Whether or not to store the first content data can be determined according to the user's desire to save the node device 1 that is the broadcast station device 31, the degree of free space in the hard disk of the broadcast station device 31, and the like. The standard is not particularly limited.

  The broadcast station apparatus 31 can also transmit a content release message for the first content data stored in the recording medium by the public information transmission unit and function as a content node, and can the content determination message be transmitted by the public determination unit? It can also be determined whether or not. Whether or not to transmit the content release message can be determined according to the necessity of copying the first content data in the content distributed storage system S1, the communication status of the node device 1 itself, the usage rate of the hard disk, and the like.

  Whether to store in a recording medium, conditions for transmitting a public message, and the like can be determined according to broadcast station setting information transmitted from the content input server 26 as shown in FIG. 11, for example. In FIG. 11, the presence or absence of storage on a recording medium is described as HD (hard disk) storage. In addition, as a content release condition, it is described that the usage rate of nothing or HD (hard disk) is less than **%. If there is no content publishing condition, it will not be released if there is no HD storage, and will be released if there is HD storage. When the content publishing condition is that the usage rate of HD is less than **%, if the usage rate of the hard disk is within that range and HD storage is available, the content is released.

  In FIG. 11, on the premise that there are a plurality of broadcast station apparatuses 31 (channels), whether to store in a recording medium for each channel, that is, for each broadcast station apparatus 31, conditions for transmitting a public message, However, the present invention is not limited to this, and may be determined for each content data to be broadcast. Moreover, these may be determined according to the policy of the broadcasting station apparatus 31 itself.

(Conversion from first content data to second content data)
The broadcast station apparatus 31 can also distribute the data as it is when distributing the first content data as the second content data, but for distributing the acquired first content data in the tree-type distribution system S2. It is possible to distribute the converted second content data by converting the format into second content data. By converting the data, it is possible to transmit the data in a format suitable for the tree type distribution system S2, and it is possible to prevent the node device 32 from being burdened by the lack of the data format.

  As one of the conversion methods, at least one of video, image, and audio included in the first content data can be deteriorated into the second content data. In this case, in the tree-type distribution system S2, the converted second content data having a lower quality than the regular first content data is distributed for content introduction. In the content distributed storage system S1, the regular first Content data can be saved. Then, a viewer who likes to view the second content data in each node device 32 of the tree distribution system S2 can acquire the regular first content data again in the content distribution storage system S1.

  As a specific conversion method, the video included in the first content data is partially thinned, a part of the video included in the first content data is selected, or the size of the video or image included in the first content data. At least one of reducing the image quality, degrading the image quality of the video or image included in the first content data, or degrading the sound quality of the audio included in the first content data can be performed.

  When the video included in the first content data is partially thinned, the video may be thinned so that one minute of video is deleted every few minutes, or a portion that is a content point like a digest Other methods may be deleted so that the specific method is not limited. When selecting a part of the video contained in the first content data, only the first 5 minutes can be selected, the first and last 3 minutes can be selected, etc. Which part of the video is selected The length is not particularly limited. When the size of the video or image included in the first content data is reduced, the size of the normal video or image is set to 70%, or the display unit such as a display is set to 80%. There is no particular limitation on how much the image is reduced and what is used as a reference. When degrading the image quality of the video or image included in the first content data, the entire video or image or the edge portion can be mosaicked, and how much the image quality is degraded is particularly limited. Not. When the sound quality of the sound included in the first content data is deteriorated, the sound quality can be roughened, noise can be mixed, etc., and how much the sound quality is deteriorated is not particularly limited. The conversion of these data usually reduces the data capacity.

  Note that the conversion method is not limited to the above, and conversion that increases the data capacity, such as conversion by adding video or other data that is a privilege to the first content data to form second content data. May be performed.

  Further, when the second content data is distributed, the second content data can be played back at an appropriate speed in the downstream node device 32 at a speed at least faster than the playback speed, that is, the second sending speed is also set. It is preferable to distribute content data. Also, additional information indicating conditions (including rate control information described later) is added to the second content data so that the second content data is transferred with the transmission speed adjusted so as to meet predetermined conditions. Is preferred.

  Whether or not to convert data can be determined according to broadcast station setting information transmitted from the content input server 26 as shown in FIG. 11, for example. In FIG. 11, only the description of sound quality degradation, screen size reduction, and only one minute is shown, but in practice, how much sound quality is degraded, how much screen size is reduced, and video It also contains information on which part of the to choose for 1 minute. In FIG. 11, on the assumption that there are a plurality of broadcast station apparatuses 31 (channels), the presence / absence of conversion of content data and how to convert it are determined for each channel, that is, for each broadcast station apparatus 31. However, the present invention is not limited to this, and may be determined for each content data to be broadcast. These may be determined according to the policy of the broadcasting station apparatus 31 itself.

(Node equipment to be a broadcasting station equipment)
In the present embodiment, the node device 1 that functions as the broadcasting station device 31 is determined by the connection destination introduction server 35. As a specific method, a node device 1 that functions as the broadcasting station device 31 is recruited at a site or the like on the network 8, and the node device 1 that can function as the broadcasting station device 31 performs registration. Then, in the connection destination introduction server 35, when a new broadcast station device 31 is required because it is desired to provide a new channel or a broadcast station device 31 capable of broadcasting in the same manner as an existing channel. The connection destination introduction server 35 selects the required number of node devices 1 from the registered node devices 1, transmits a broadcast station start request message to the node devices 1, and transmits the node device 1 to the broadcast station device 31. To function as. The node device 1 that has received the broadcast station start request message acquires the broadcast program file from the content input server 26, starts broadcasting as the broadcast station device 31, and the connection destination introduction server 35 includes the node device 1 Registration to function as the broadcasting station device 31 is performed.

  On the other hand, in the connection destination introduction server 35, since there are few viewers (downstream node devices 32) of a predetermined channel, the channel itself is stopped, or the flow is integrated into the broadcasting station device 31 of another same channel. When the broadcast station device 31 is no longer needed, the connection destination introduction server 35 transmits a broadcast station stop request message to the node device 1 as the broadcast station device 31, and the broadcast station device of the node device 1 31 function is stopped. The node device 1 that has received the broadcast station stop request message deletes the owned broadcast program file, stops broadcasting, and the connection destination introduction server 35 has the function of the broadcast station device 31 in the node device 1. Register that it has stopped (cancel broadcast station registration). Before transmitting the broadcast station stop request message, the connection destination introduction server 35 transmits another broadcast station device 31 or a node device downstream thereof to each node device 32 connected downstream of the node device 1. The message may be transmitted so as to connect to the broadcast station device 32, and the broadcast station stop message may be transmitted after the node device 32 downstream of the broadcast station device 31 disappears.

  For the node device 1 registered to function as the broadcasting station device 31 at the site or the like, when the connection destination introduction server 35 transmits a broadcasting station start message, the message cannot be transmitted (registered address). Is wrong, or the node device 1 is not connected to the network), the connection destination introduction server 35 may delete the registration to the site or the like.

  In this way, by determining the node device 1 that the connection destination introduction server 35 functions as a broadcast station device, the broadcast manager having the connection destination introduction server 35 prepares the number of broadcast station devices 31 corresponding to the demand. The distribution of the second content data in the tree-type distribution system S2 can be managed.

(Timing for distributing the second content data, etc.)
Further, the node device 1 as the broadcast station device 31 acquires the broadcast program file from the content input server 26 as described above, and broadcasts (distributes the second content data) along the broadcast program file. The second content data determined by the input server 26 may be transmitted in that order or timing. Therefore, the node device 1 does not need to determine the order and timing for distributing the second content data, and the burden does not increase. In the present embodiment, the broadcast program file will be described as an example, but the present invention is not limited to this. For example, in accordance with the timing at which the node device 1 as the broadcast station device 31 distributes the second content data, the content input server 26 says “Next, distribute the content with the content ID: *****”. An instruction is transmitted to the node device 1, and the node device 1 transmits a query for the content in the content distributed storage system S1 at the timing when this instruction is received, acquires first content data, and the tree-type distribution system S2 You may distribute.

[5. Configuration of each device constituting content distribution system]
With reference to FIGS. 12 to 15, configurations of the node devices 1 and 32, the contact node introduction server 25, the connection destination introduction server 35, and the content input server 26 constituting the content distribution system S will be described.

[5.1. Node device configuration]
First, with reference to FIG. 12, the configuration and function of the node devices 1 and 32 (both are the same and will be referred to as the node device 1 in the following description) will be described. The configuration of each node device 1 is the same. FIG. 12 is a diagram illustrating a schematic configuration example of the node device 1.

  As shown in FIG. 12, each node device 1 includes a CPU 11 having an arithmetic function, a ring buffer memory 121 for temporarily storing received content data, an operating system 122, a stream control program 123, and an encoding included in the content data. Screen control program 124 that decodes (decompresses or decodes) video data (video information) and the like, topology control program 125, and encoded audio data (audio information) included in content data (data A music decoder 126 and a broadcast content control program 127 (decompressing and decoding, etc.), a main storage device 12 composed of a working RAM, a ROM for storing various data and programs, etc. Controls the connection between the hard disk device 13 as a recording medium composed of HD or the like for storing and storing (stores) the dex information, the DHT, the program, etc., and peripheral devices such as the hard disk device 13 and the input unit, and information A peripheral device control chip 14 for transmitting the video, a video chip 15 for performing a predetermined drawing process on the decoded video data and the like and outputting it as a video signal, and displaying a video based on the video signal output from the video chip 15 A built-in display 16 such as a CRT or a liquid crystal display; a sound source chip 17 for converting the decoded audio data into an analog audio signal after D (Digital) / A (Analog) conversion and amplifying it by an amplifier; and the sound source Built-in monitor that outputs audio signals output from chip 17 as sound waves Infrared port as an input unit that receives input from the speaker 18 and the external remote controller 23 and receives an instruction from the user and gives an instruction signal corresponding to the instruction to the CPU 11 (in addition, for example, a keyboard 19) and a network interface 21 for controlling communication of information with other node devices 1 via the network 8 via the router 24 and the like. The CPU 11, the main storage device 12, the peripheral device control chip 14, the video chip 15, the sound source chip 17, and the network interface 21 are connected to each other via a system bus 22. The network interface 21 is connected to an external router 24 and the like via the network 8. The infrared port 19 receives an instruction signal from the user-input remote controller 23 and transmits the signal to the peripheral device control chip 14.

  The CPU 11 performs overall control of the node device 1 by executing various programs stored in the main storage device 12 and the like, and according to an instruction signal from an input unit such as the remote controller 23. The content data registration process is performed. The node device 1 functions as a broadcast station device 31, a node device that transmits (transfers) information, a node device that receives information, and the like according to a program to be executed. In addition, the CPU 11 of the node device 1 includes a first content data acquisition unit, a second content data distribution unit, a storage determination unit, a public information transmission unit, a request reception unit (content request), a first content data transmission unit, It functions as a disclosure determination unit, a search unit (query), a request transmission unit (content request), a conversion unit, and a content determination unit.

[5.2. Configuration of contact node introduction server]
Next, the configuration and function of the contact node introduction server 25 will be described with reference to FIG. FIG. 13 is a diagram illustrating a schematic configuration example of the contact node introduction server 25.

  As shown in FIG. 13, the contact node introduction server 25 includes a CPU 251 having an arithmetic function, a terminal management program 2521, an operating system 2522, a contact node introduction program 2523, etc., and stores work RAM, various data and programs. A main storage device 252 including a ROM, a hard disk device 253 including an HD for storing and storing a terminal management database, a program, and the like, and peripheral devices such as the hard disk device 253 and an input unit A peripheral device control chip 254 that controls connection and transmits information; a video chip 255 that outputs a video signal to display images such as characters and figures necessary as a GUI (graphical user interface) of the operating system 2522; The video chip A display 2561 such as a CRT or a liquid crystal display that displays an image based on the video signal output from 55, and an input unit that receives an instruction from the user and provides an instruction signal corresponding to the instruction to the CPU 251 via the peripheral device control chip 254 And a network interface 257 for controlling communication of information with the other node devices 1 via the router 259 and the like through the network 8, and a CPU 251 and a main memory. The device 252, the peripheral device control chip 254, the video chip 255, and the network interface 257 are connected to each other via a system bus 258. The video chip 255 is connected to an external display 2561, and the peripheral device control chip 254 is connected to an external keyboard 2562 and a mouse 2563. The network interface 257 is connected to an external router 259 and the like via the network 8.

  The CPU 251 performs overall control of the entire contact node introduction server 25 by executing various programs stored in the main storage device 252 and the like. Specifically, the CPU 251 can change the conditions in the terminal management program or the policy in the contact node introduction program in accordance with an instruction signal from the input unit such as the keyboard 2562 or the mouse 2563. In response to the contact node introduction request message from the participating node device 1 received through the network 8 or the network interface 257, the CPU 251 determines the contact node using the contact node introduction program 2523, and the location information of the contact node ( IP address etc.) is returned as contact node information.

[5.3. Connection destination server configuration, etc.]
Next, the configuration and function of the connection destination introduction server 35 will be described with reference to FIG. FIG. 14 is a diagram illustrating a schematic configuration example of the connection destination introduction server 35.

  As shown in FIG. 14, the connection destination introduction server 35 includes a CPU 351 having a calculation function, a terminal management program 3521, an operating system 3522, a topology control program 3523, a connection destination introduction program 3524, and the like. And a main storage device 352 composed of a ROM or the like for storing programs, a hard disk device 353 composed of an HD or the like for storing (storing) a topology database, a terminal management database, a program, etc., a hard disk device 353, Peripheral device control chip 354 that controls connection with peripheral devices such as an input unit and transmits information, and a video signal for displaying images such as characters and figures necessary as a GUI (graphical user interface) of operating system 3522 Output A video chip 355, a display 3561 such as a CRT or a liquid crystal display for displaying video based on the video signal output from the video chip 355, an instruction signal according to the instruction received from the user, and a peripheral device control chip 354 A keyboard 3562 and a mouse 3563 as input units to be provided to the CPU 351, and a network interface 357 for controlling communication of information with the other node devices 1 and the like via the network 8 via the router 359 and the like. The CPU 351, the main storage device 352, the peripheral device control chip 354, the video chip 355, and the network interface 357 are connected to each other via a system bus 358. The video chip 355 is connected to an external display 3561, and the peripheral device control chip 354 is connected to an external keyboard 3562 and a mouse 3563. The network interface 357 is connected to an external router 359 and the like via the network 8.

  The CPU 351 performs overall control of the entire connection destination introduction server 35 by executing various programs stored in the main storage device 352 and the like. Specifically, the CPU 351 changes conditions or the like in the terminal management program or changes a policy or the like in the topology control program or the connection destination introduction program in response to an instruction signal from the input unit such as the keyboard 3562 or the mouse 3563. Can do. Further, the CPU 351 determines a connection destination candidate using the topology control program 3523 and the connection destination introduction program 3524 in response to the connection destination candidate request Sc received from the node device 32 via the network 8 or the network interface 357, and connects to the connection destination candidate. A candidate notification Nk {} is returned.

[5.4. Content input server configuration]
Next, the configuration and function of the content input server 26 will be described with reference to FIG. FIG. 15 is a diagram illustrating a schematic configuration example of the content input server 26.

  As shown in FIG. 15, the content input server 26 includes a CPU 261 having a calculation function, a catalog management program 2621, an operating system 2622, a content control program 2623, and the like, a working RAM, a ROM for storing various data and programs, and the like. A main storage device 262 made up of, a hard disk device 263 made up of an HD etc. for storing and storing broadcast program files, catalog lists, contents, programs, etc., and peripherals such as the hard disk device 263 and the input unit Peripheral device control chip 264 that controls connection with devices and transmits information, and a video chip that outputs video signals to display images such as characters and figures necessary as a GUI (graphical user interface) of operating system 2622 26 A display 2661 such as a CRT or a liquid crystal display that displays an image based on the video signal output from the video chip 265, and an instruction signal according to the instruction received from the user via the peripheral device control chip 264 A keyboard 2662 and a mouse 2663 as input units to be provided to the CPU 261, and a network interface 267 for performing communication control of information with the other node devices 1 and the like via the network 8 via the router 269 and the like. The CPU 261, main storage device 262, peripheral device control chip 264, video chip 265, and network interface 267 are connected to each other via a system bus 268. The video chip 265 is connected to an external display 2661, and the peripheral device control chip 264 is connected to an external keyboard 2662 and a mouse 2663. The network interface 267 is connected to an external router 269 and the like via the network 8.

  The CPU 261 executes the various programs stored in the main storage device 262 and the like, thereby performing overall control of the content input server 26 as a whole. Specifically, the CPU 261 can change conditions or the like in the catalog management program or change a policy or the like in the content control program in accordance with an instruction signal from an input unit such as the keyboard 2662 or the mouse 2663. Further, the CPU 261 transmits broadcast station setting information and a broadcast program file to the broadcast station apparatus 31 through the network 8 and the network interface 267, and transmits catalog list information in response to the received catalog list request from the node apparatus 1. Or the content distributed and stored in the content distributed storage system S1 is transmitted (input) to the desired node device 1.

  In the catalog list, the above-described auxiliary information of the first content data is a list, but in addition to this, a content ID may be associated. In the node device 1, when the catalog list is acquired, content may be specified from the catalog list, a content ID may be generated each time a query is transmitted, and a content ID corresponding to the content specified from the catalog list may be transmitted. You may get it.

  In addition, regarding the broadcast program file described above, the content input server 26 stores a broadcast program file for each channel. Further, the content input server 26 possesses the above-mentioned broadcast station setting information, and adds the broadcast station setting information corresponding to the channel when transmitting the broadcast program file to the node device 1 functioning as a broadcast station. Can be sent. These broadcast program files and broadcast station setting information are created according to the settings of the broadcast manager.

[6. Operation in content distribution system of this embodiment]
Next, the operation of each device in the content distribution system S of the present embodiment will be described with reference to FIGS.

[6.1. Operation of node equipment]
First, the operation of the node device 1 according to the present embodiment will be described with reference to FIGS. 16 mainly shows the operation when participating in the tree distribution system S2, and FIG. 17 mainly shows the operation when participating in the content distributed storage system S1, and FIG. FIG. 19 mainly shows the operation in the case where the acquired first content data, which is a feature of the present invention, is distributed as second content data (broadcast content data) in the tree-type distribution system S2. In FIG. The operation when functioning as the station apparatus 31 is shown. 20 shows the system participation process at step S3, FIG. 21 shows the input content reception process at step S26, FIG. 22 shows the content search process at step S45, and FIG. 23 shows step S61. The content data acquisition process is shown.

  When the CPU 11 of the node device 1 recognizes that the power of the node device 1 is turned on by the user input remote controller 23 or the like, the CPU 11 starts the processing (start).

  When the processing is started, the CPU 11 initializes various settings such as the program of the node device 1 (step S1), and transmits a notification of participation in the tree distribution system S2 to the connection destination introduction server 35 (step S2). . Next, the CPU 11 performs a participation process in the content distributed storage system S1 (step S3). The participation process in the content distributed storage system S1 in step S3 will be described later with reference to FIG.

  Next, the CPU 11 determines whether or not there is a channel selection instruction from the user from the user-input remote control 23 or the like (step S4). When there is a channel selection instruction from the user (step S4; YES), the CPU 11 determines whether there is a node device 1 (upstream node device 1) connected to the upstream side (step S5). When there is the upstream node device 1 (step S5; YES), the CPU 11 transmits information indicating that the current upstream node device 1 is requested to stop transmission of broadcast content data (broadcast content stream) (step S6). . Next, the CPU 11 transmits, to the connection destination introduction server 35, a connection destination candidate request Sc for requesting a candidate for the node device 1 to be a connection destination in order to view the broadcast of the selected channel (broadcast station device) ( Step S7). In Step S5, when there is no upstream node device 1 (Step S5; NO), the process proceeds to Step S7 without going through Step S6.

  Next, the CPU 11 determines whether or not the power is off (step S8). If the power is not off (step S8; NO), the CPU 11 returns to step S4.

  In step S4, when there is no channel selection instruction from the user (step S4; NO), the CPU 11 determines whether or not the candidate of the upstream node device 1 that is the connection destination is received from the connection destination introduction server 35. (Step S9). When the candidate for the upstream node device 1 is received from the connection destination introduction server 35 with respect to step S7 described above (step S9; YES), the CPU 11 selects the upstream node from the acquired candidates for the upstream node device 1. One device 1 is selected (step S10). Next, the CPU 11 is connected as the node device 1 (downstream node device 1) connected downstream of the selected upstream node device 1 (step S11), and requests that the selected upstream node device 1 start distribution of broadcast content data. Is transmitted (step S12). Next, the CPU 11 transmits a report on participation in the tree topology to the connection destination introduction server 35 (step S13), and returns to step S8.

  In step S9, when the candidate for the upstream node device 1 is not received from the connection destination introduction server 35 (step S9; NO), the CPU 11 determines whether or not the broadcast content data packet is received from the upstream node device 1. Is determined (step S14). When the broadcast content data packet is received from the upstream node device 1 (step S14; YES), the CPU 11 sequentially transfers the packet to the downstream node device 1 (step S15). At this time, the received broadcast content data packets are sequentially stored in the ring buffer 121, and then the CPU 11 obtains the packets from the ring buffer 121 and reproduces the broadcast content data (step S16), and returns to step S8. .

  In step S14, when the broadcast content data packet is not received from the upstream node device 1 (step S14; NO), the CPU 11 sends a broadcast content data transmission start request or transmission stop request from the node device 1 serving as the downstream node device. Is determined (step S17). When the broadcast content data transmission start request or the transmission stop request is received (step S17; YES), the CPU 11 starts or stops the transmission of the broadcast content data according to the request (step S18). Return to S8.

  If it is determined in step S17 that a broadcast content data transmission start request or transmission stop request has not been received (step S17; NO), the processing moves to FIG. 17, and the CPU 11 determines whether or not a content disclosure message has been received. (Step S19). When the content release message is received (step S19; YES), the CPU 11 registers location information such as the content ID and IP address of the first content data as content index information (step S20). Next, the CPU 11 determines whether or not the node device itself is a root node with respect to the content release message (step S21). If the node itself is not the root node (step S21; NO), the CPU 11 transfers the received message (in this case, the content disclosure message) to the next node device 1 (step S22), and returns to step S8. If the node itself is the root node (step S21; YES), the process returns to step S8 without transferring the message received as it is (content disclosure message here).

  In step S19, when the content release message has not been received (step S19; NO), the CPU 11 determines whether or not a content deletion message has been received (step S23). When the content deletion message is received (step S23; YES), the CPU 11 determines from the content index information that the first content data corresponding to the content deletion message is stored in the content index information. The location information and the like of the content node of the first content data is deleted (step S24), and the process proceeds to step S21. Return to Step 8.

  In step S23, when the content deletion message is not received (step S23; NO), the CPU 11 determines whether or not the input content data is received from the content input server 26 (step S25). When the input content data is received from the content input server 26 (step S25; YES), the CPU 11 performs input content reception processing (step S26) and returns to step S8. The input content reception process will be described later with reference to FIG.

  In step S25, when the input content data is not received from the content input server 26 (step S25; NO), the CPU 11 as the request receiving unit requests the content transmission from the other node device 1 for the first content data. It is determined whether information has been received (step S27). When the content transmission request information is received (step S27; YES), the CPU 11 as the first content data transmission means distributes the corresponding first content data to the requested node device 1 (step S28), and step Return to S8. At this time, it is assumed that the first content data includes rate control information, and a distribution rate at which the first content data is distributed as broadcast content data is determined according to the rate control information. Note that this rate control information is different for each content. Although it may not be described in the steps described later, rate control information is also included in the transmitted second content data.

  If the content transmission request information has not been received in step S27 (step S27; NO), the process proceeds to FIG. 18, where the node device 1 is the distribution source node device in the present invention, and the broadcast station device in the present embodiment. It functions as 31. The CPU 11 as the first content data acquisition means determines whether or not the first content data packet for broadcast content data has been received as a result of the broadcast content data acquisition process in step S61 described later (step S29). When the broadcast content data packet is received (step S29; YES), the CPU 11 as the storage determination means determines whether or not the broadcast content data is stored in the HD (hard disk) in the hard disk device 13 (step S29). S30). Whether or not to save the broadcast content data, whether to convert data to be described later, or whether to release the saved content, conditions set by the user of the node device 1 or the like, It depends on the above-mentioned broadcast station setting information (see FIG. 11), information set for each broadcast content data, and the like. When the node device 1 functions as a broadcasting station device with the channel number “3” in FIG. 11, it is determined to store the broadcast content data.

  When the broadcast content data is stored in the hard disk (step S30; YES), the CPU 11 sequentially stores the received broadcast content data packets in the hard disk (the recording medium in the present invention) (step S31). Next, the CPU 11 determines whether or not all the packets for one broadcast content data are prepared (step S32), and when all the packets for the broadcast content data are not prepared (step S32; NO), it will be described later. Proceed to step S37. Until all the broadcast content data is obtained, step S32; NO, S37 to S40, S8; NO, S4; NO, S9; NO, S14; NO, S17; NO, S19; NO, S23; NO, S27; NO, S29; YES, S30; YES, S31 are repeated, and when the broadcast content data is prepared, a public message is transmitted as necessary, as will be described later.

  In step S32, when all the broadcast content data packets have been prepared (step S32; YES), the CPU 11 as the disclosure determination unit determines whether or not to release the stored content data as the first content data ( Step S33). When the node device 1 functions as a broadcasting station device having the channel number “3” in FIG. When the saved content data is disclosed as the first content data (step S33; YES), the CPU 11 uses the content ID of the saved first content data and its location information (such as the IP address of the own node device) as the content. Registration in the index information (step S34). Next, the CPU 11 as the public information transmitting means determines whether or not the node device 1 itself becomes a root node when considering the content ID of the first content data (step S35). When the node device 1 itself is not the root node (step S35; NO), the CPU 11 as the public information transmitting means sends the content public message about the stored first content data to the other node devices 1 (to the root node). (Step S36), and the process proceeds to step S37. On the other hand, if the node device 1 itself is a root node in step S35 (step S35; YES) and if the stored content data is not disclosed as the first content data in step S33 described above (step S33; NO) ), The process proceeds to step S37 without performing the process.

  The CPU 11 starts a packet generation process for broadcast content data (step S37). Next, the CPU 11 determines whether or not the broadcast content data is to be converted (step S38). When the broadcast content data is to be converted (step S38; YES), the CPU 11 as the conversion means broadcasts by a predetermined method. The content data is converted (step S39), and the CPU 11 as the second content data distribution means starts transmitting the broadcast content data packet converted to the downstream node device 1 (step S40). When the node device 1 functions as a broadcasting station device having the channel number “3” in FIG. 11, the broadcast content data is converted into predetermined one-minute data and transmitted. When the broadcast content data is not converted in step S38 (step S38; NO), the CPU 11 as the second content data distribution unit uses the acquired packet of the first content data as it is as the broadcast content data as a downstream node device. 1 starts transmission (distribution) (step S40). In step S40, conversion such as adjusting the transmission speed, starting the broadcast after waiting for the broadcast content data to be broadcast, or adding the above-described additional information can be performed.

  When the broadcast content data is not stored in the hard disk in step S30 (step S30; NO), the CPU 11 temporarily stores the first content data packet in the ring buffer 121 and converts the broadcast content data. Whether or not (step S41). When the broadcast content data is to be converted (step S41; YES), the CPU 11 as the conversion means converts the broadcast content data by a predetermined method (step S42), and the broadcast content data packet converted to the downstream node device 1 is converted. Is started (step S43). In step S41, when the broadcast content data is not converted (step S41; NO), the CPU 11 as the second content data distribution unit directly uses the acquired first content data as the broadcast content data to the downstream node device 1. Transmit (step S43). Next, the process returns to step S8. Steps S41 to S43 are the same as steps S38 to S40 described above.

  When the broadcast content data packet is not received in step S29 (step S29; NO), the CPU 11 determines whether or not a content search message (query) has been received (step S44). When the query is received (step S44; YES), the CPU 11 performs a content search process (step S45) and returns to step S8. The content search process in step S45 will be described later with reference to FIG.

  In step S44, if no query has been received (step S44; NO), the CPU 11 has received content node information (location information such as the IP address of the content node) as a result of the content search processing in S45. Is determined (step S46). When the content node information is received (step S46; YES), the CPU 11 as the request transmission unit transmits the content transmission request information to the content node (step S47).

  In step S46, when the content node information is not received (step S46; NO), the process proceeds to FIG. 19, and the CPU 11 determines whether or not a participation message to the content distributed storage system S1 is received (step S46). S48). When the participation message is received (step S48; YES), the participation message includes location information of the node device (participating node device) that is the transmission source of the participation message and information on the stage to be transmitted from the table information. Therefore, the CPU 11 transmits information on the corresponding stage from the table information possessed to the participating node device (step S49). Next, the CPU 11 determines whether or not the node device 1 itself is the root node of the node ID of the participating node (step S50). When the node device 1 itself is not the root node (step S50; NO), the CPU 11 transfers the participation message to the next node device (step S51), and returns to step S8. If the node device 1 itself is the root node (step S50; YES), the process returns to step S8 without transferring the participation message.

  If the participation message has not been received in step S48 (step S48; NO), it is determined whether a broadcast station start request message has been received from the connection destination introduction server 35 (step S52). When the broadcast station start request message is received (step S52; YES), the CPU 11 acquires a broadcast program file indicating the content to be broadcast, its order, time zone, and the like from the content input server 26, and the broadcast program file. Broadcasting is started along (step S53). Next, the CPU 11 registers to the connection destination introduction server 35 to function as a broadcasting station device (step S54), and returns to step S8.

  In step S52, when the broadcast station start request message has not been received (step S52; NO), the CPU 11 determines whether or not a broadcast station stop request message has been received from the connection destination introduction server 35 (step S55). ). When the broadcast station stop request message is received (step S55; YES), the CPU 11 deletes the broadcast program file used for the current broadcast and stops the broadcast (step S56). Next, the CPU 11 registers to the connection destination introduction server 35 that the function serving as the broadcasting station device is canceled (step S57), and returns to step S8.

  If the broadcast station stop request message has not been received in step S55 (step S55; NO), the CPU 11 has already established or already established a connection from the other node device 1 to the downstream in the tree distribution system S2. It is determined whether or not there is a request for disconnection to disconnect (step S58). When there is a request for connection establishment or connection disconnection from another node device 1 (step S58; YES), the CPU 11 establishes a connection with another node device 1 or disconnects the connection according to the request. (Step S59), the process returns to Step S8. When a connection is established with another node device 1 in step S59, broadcasting is started subsequently, and preparations for transmitting broadcast content data are made.

  In step S58, when there is no connection establishment or connection disconnection request from another node device 1 (step S58; NO), the CPU 11 determines the broadcast content data based on the broadcast program file (see FIG. 10A). It is determined whether or not it is time to acquire (step S60). When it is time to acquire broadcast content data (step S60; YES), the CPU 11 performs a broadcast content acquisition process (step S61) and returns to step S8. The broadcast content acquisition process in step S61 will be described later with reference to FIG.

  Here, when the power is turned off in step S8, it is determined that the power is off (step S8; YES), and the processing in the node device 1 is ended (end). 16 to FIG. 19, connectors 1 to 6 are used for the portions to which the flowcharts are connected.

  Next, the participation process in the content distributed storage system S1 in step S3 will be described with reference to FIG.

  When the participation process to the content distributed storage system S1 starts (start: step S3), the CPU 11 of the node device 1 transmits a contact node introduction request message to the contact node introduction server 25 (step S71). Next, the CPU 11 acquires contact node information from the contact node introduction server 25 (step S72), and transmits a participation message to the contact node (step S73). Next, the CPU 11 receives table information from the contact node and each node device 1 to which the participation message has been transferred (step S74).

  Next, the CPU 11 updates the possessed routing table based on the received table information (step S75), and requests the catalog list from the content input server 26 (step S76). Next, the CPU 11 receives the catalog list from the content input server 26 (step S77), and returns to the original step S3 in FIG. 16 (return). During such participation processing, the node device 1 functions as a participating node.

  Next, the input content reception process in step S26 will be described with reference to FIG.

  When the input content reception process is started (start: step S26), the CPU 11 of the node device 1 stores the received first content data in the HD of the hard disk device 13 (step S81). Next, the CPU 11 registers the content ID of the stored first content data and the location information thereof (such as the IP address of the own node device) in the content index information (step S82). Next, the CPU 11 determines whether or not the node device 1 itself becomes a root node when considering the content ID of the first content data (step S83). When the node device 1 itself is not the root node (step S83; NO), the CPU 11 transmits a content release message for the saved first content data to another node device 1 (toward the root node) ( In step S84, the process returns to step S26 in FIG. 17 (return). On the other hand, if the node device 1 itself is a root node (step S83; YES), the process returns to step S26 in FIG. The node device 1 that has performed such input content reception processing functions as a content node.

  Next, the content search process in step S45 will be described with reference to FIG.

  When the content search process starts (Start: Step S45), the CPU 11 of the node device 1 acquires the content ID of the first content data searched from the content search message (query) (Step S91). Next, the CPU 11 determines whether or not the content ID exists in the content index information possessed (step S92). When the content ID exists in the content index information (step S92; YES), the CPU 11 acquires content node information corresponding to the content ID from the content index information (step S93), and uses the content node information as the content. The search message is transmitted to the source node device (step S94). On the other hand, in step S92, when the content ID does not exist in the content index information (step S92; NO), the content search message is transferred to another node device 1 (step S95). When these steps S94 and S95 are completed, the process returns to the original step S45 in FIG. 18 (return).

  Next, the broadcast content data acquisition process in step S61 will be described with reference to FIG.

  When the broadcast content data acquisition process starts (start: step S61), the CPU 11 of the node device 1 acquires the content ID of the broadcast content data from the broadcast program file (step S101), and stores the content data corresponding to the content ID. It is determined whether or not (step S102). If the corresponding content data is not stored (step S102; NO), it is determined whether or not the content ID exists in the content index information possessed (step S103). If the content ID information is present in the possessed content index information (step S103; YES), the content node information is acquired from the content index information (step S104), and the CPU 11 as the request transmission means sends the content node information to the content node. Transmission request information is transmitted (step S105). On the other hand, in step S103, when the content ID does not exist in the content index information (step S103; NO), the CPU 11 as the search means transmits a content search message with the content ID added to the other node device 1. (Step S106). When these steps S105 and S106 are completed, the process returns from step S61 in FIG. 19 to step S8 in FIG. 16 (return). If the corresponding content data is stored in step S102 (step S102; YES), it is not necessary to acquire the content data, so the same processing as steps S41, S42, and S43 is performed without performing the above processing. The transmission of the broadcast content packet to the downstream node device is started, and the process returns from step S61 in FIG. 19 to step S8 in FIG. 16 (return).

[6.2. Operation of contact node introduction server]
Next, with reference to FIG. 24, the operation of the contact node introduction server 25 of this embodiment will be described.

  When the CPU 251 of the contact node introduction server 25 recognizes that the contact node introduction service is started by an external instruction via the network interface 257 or an input from the input unit such as the keyboard 2562, the process is started ( start).

  When the process is started, the CPU 251 initializes various settings such as the program of the contact node introduction server 25 (step S111), and determines whether there is a contact node introduction request message from the node device 1 (step S112). ). If there is a contact node introduction request message (step S112; YES), the CPU 251 sends node information (location information such as an IP address) of the candidate contact node to the node device 1 that is the source of the contact node introduction request message. Transmit (step S113), and proceed to step S114. If there is no contact node introduction request message in step S112, the process proceeds to step S114 without passing through step S113. Next, the CPU 251 determines whether or not to end the contact node introduction server service, based on input from the keyboard 2562 or the like, an instruction via the network interface 257, or the like (step S114). If the contact node introduction server service is not terminated (step S114; NO), the process returns to step S112. If the contact node introduction server service is terminated (step S114; YES), the process is terminated (end).

[6.3. Connection destination server operation]
Next, the operation of the connection destination introduction server 35 of this embodiment will be described with reference to FIG.

  When the CPU 351 of the connection destination introduction server 35 recognizes that the connection destination introduction service is started by an external instruction via the network interface 357 or an input from an input unit such as the keyboard 3562 or the like, the CPU 351 starts the processing ( start).

  When the process is started, the CPU 351 initializes various settings such as the program of the connection destination introduction server 35 (step S121), and determines whether or not there is a participation notification from the node device 1 (step S122). If there is a participation notification (step S122; YES), the CPU 351 registers the location information of the node device that is the transmission source of the participation notification in the terminal management database (step S123), and whether or not to end the connection destination introduction server service. Alternatively, the determination is made based on an input from the keyboard 3562 or the like, an instruction via the network interface 357, or the like (step S124). If the contact node introduction server service is not terminated (step S124; NO), the process returns to step S122.

  In step S122, when there is no participation notification (step S122; NO), the CPU 351 determines whether there is a registration request or a cancellation request from the broadcast station apparatus (step S125). When there is a broadcast station apparatus registration request or cancellation request (step S125; YES), the CPU 351 registers or cancels the location information of the broadcast station apparatus in the terminal management database in response to the request (step S126). ). Next, the CPU 351 registers or cancels the channel information of the broadcasting station device in the topology database (step S127), and returns to step S124.

  In step S125, when there is no broadcast station device registration request or cancellation request (step S125; NO), the CPU 351 determines whether or not there is a connection destination introduction request Sc from the node device 1 (step S128). When there is a connection destination introduction request Sc (step S128; YES), the CPU 351 acquires the location information of the node device 1 that is a connection destination candidate from the topology database (step S129), and connects the connection destination to the requesting node device. The location information of the node device 1 that is a candidate for the connection is transmitted as a connection destination candidate notification Nk {} (step S130), and the process returns to step S124.

  In step S128, when there is no connection destination introduction request Sc (step S128; NO), the CPU 351 receives a broadcast station opening request from the broadcast manager's terminal device (not shown) or the input unit such as the keyboard 3562. It is determined whether or not (step S131). If there is a broadcast station establishment request (step S131; YES), the CPU 351 selects the node device 1 to be the broadcast station device 31 from the terminal management database (step S132), and requests the selected node device 1 to start a broadcast station. The message is transmitted (step S133), and the process returns to step S124. Although not shown in FIG. 25, when there is a request from the broadcast manager to stop the broadcast station, the broadcast station stop is similarly applied to the node device functioning as the broadcast station device 31. Send a request message.

  In step S131, when there is no broadcast station establishment request (step S131; NO), the CPU 351 determines whether there is a topology participation report from the node device 1 (step S134). When there is a topology participation report from the node device 1 (step S134; YES), the CPU 351 registers information on the topology change due to the node device 1 participating in the topology in the topology database (step S135). The process returns to step S124. In step S134, when there is no topology participation report from the node device 1 (step S134; NO), the process returns to step S124.

  Here, when the contact node introduction server service is terminated in step S124 (step S124; YES), the process is terminated (end).

[6.4. Operation of content input server]
Next, the operation of the content input server 26 of this embodiment will be described with reference to FIG.

  When the CPU 261 of the content input server 26 recognizes that the connection destination introduction service is to be started by an instruction from the outside via the network interface 267 or an input from the input unit such as the keyboard 2662, the processing starts (Start). ).

  When the process is started, the CPU 261 initializes various settings such as the program of the content input server 26 (step S141), and determines whether or not there is a content input instruction from the administrator device of the content distributed storage system S1. Judgment is made (step S142). When there is a content input instruction (step S142; YES), the CPU 261 updates the management table of the content ID corresponding to the new first content data to be input (step S143), and the new first in the catalog list. Information on the content data is updated (step S144), and the new first content data is distributed to one or a plurality of node devices 1 determined at random in the content distributed storage system S1 (step S145). Next, the CPU 261 determines whether or not to end the content input server service, based on an input from the keyboard 2662 or the like, an instruction via the network interface 267, or the like (step S146). If the content input server service is not terminated (step S146; NO), the process returns to step S142.

  If there is no content input instruction in step S142 (step S142; NO), the CPU 261 determines whether there is a catalog list transmission request from the node device 1 (step S147). If there is a catalog list transmission request (step S147; YES), the CPU 261 transmits the catalog list information to the node device 1 that has transmitted the catalog list transmission request (step S148), and the process returns to step S146.

  If there is no catalog list transmission request in step S147 (step S147; NO), the CPU 261 determines whether or not there is a broadcast program file transmission request from the node apparatus 1 functioning as the broadcast station apparatus 31 (step S147; NO). Step S149). If there is a broadcast program file transmission request (step S149; YES), the CPU 261 transmits the broadcast program file to the node device 1 that is the transmission source of the broadcast program file transmission request (step S150), and returns to step S146. . In step S149, when there is no broadcast program file transmission request from the node device 1 (step S149; NO), the process returns to step S146.

  Here, in step S146, when the content input server service is ended (step S146; YES), the process is ended (end).

[7. Variant]
Although the above-mentioned embodiment was described as an example of the present invention, the present invention is not limited to this, and for example, the following modifications can be made.

[7.1. First variant]
In the above-described embodiment, the node device 1 has been described as functioning as the broadcast station device 31. However, the content distribution system S may include the broadcast station device 31 for the broadcast station separately from the normal node device 1. Good. Such a broadcasting station apparatus 31 also needs to participate in the content distribution storage system S1. The content distribution system S having the broadcasting station device 31 will be described below.

  The configuration and function of the broadcast station apparatus 31 will be described with reference to FIG. FIG. 27 is a diagram illustrating a schematic configuration example of the broadcast station device 31.

  As shown in FIG. 27, the broadcast station apparatus 31 includes a CPU 311 having an arithmetic function, a ring buffer memory 3121 that temporarily stores received first content data, an operating system 3122, a stream control program 3123, and content data. A screen control program 3124 that decodes encoded video data (video information), etc. (data decompression, decoding, etc.), a topology control program 3125, and encoded audio data (audio information) included in content data (decodes) A main storage device 312 comprising a music decoder 3126 and a broadcast content control program 3127 (data decompression, decoding, etc.), a working RAM, a ROM storing various data and programs, and the first content A hard disk device 313 as a recording medium composed of an HD for storing and storing data, content index information, the DHT and programs, etc., and peripheral devices such as the hard disk device 313 and an input unit. A peripheral device control chip 314 that controls and transmits information; a video chip 3151 that performs a predetermined drawing process on the decoded video data and the like and outputs the video signal; and a video signal output from the video chip 3151 A display 3161 such as a CRT or a liquid crystal display for displaying an image based on the image, and a sound source chip 3152 for converting the decoded audio data into an analog audio signal by D (Digital) / A (Analog) conversion and then amplifying it with an amplifier and outputting it. Output from the sound source chip 3152 A speaker 3162 that outputs an audio signal as a sound wave, and a keyboard 3163 and a mouse 3164 as input units that receive an instruction from the user and give an instruction signal corresponding to the instruction to the CPU 311 (in addition, for example, an operation remote controller, An operation panel or the like) and a network interface 317 for performing communication control of information with the other node devices 1 and the like via the router 319 and the like through the network 8, and a CPU 311 and a main memory The device 312, the peripheral device control chip 314, the video chip 3151, the sound source chip 3152, and the network interface 317 are connected to each other via a system bus 318. The network interface 317 is connected to an external router 319 or the like via the network 8.

  The CPU 311 performs overall control of the broadcasting station apparatus 31 by executing various programs stored in the main storage device 312 and the like, and responds to instruction signals from an input unit such as a keyboard 3163. Thus, content data registration processing and the like are performed. Further, the CPU 311 of the broadcast station apparatus 31 includes a first content data acquisition unit, a second content data distribution unit, a storage determination unit, a public information transmission unit, a request reception unit (content request), and a first content data transmission unit according to the present invention. , Function as public determination means, search means (query), request transmission means (content request), conversion means. It is assumed that the broadcast station apparatus 31 has received a broadcast program file indicating the order, time, content ID, and the like of broadcast content data to be distributed from the content input server 26.

  Next, the operation of the broadcast station apparatus 31 will be described with reference to FIG.

  When the CPU 311 of the broadcasting station apparatus 31 recognizes that the broadcasting station apparatus 31 itself has been turned on by a power switch (not shown) or the like, the CPU 311 starts the processing (start).

  When the process is started, the CPU 311 initializes various settings such as the program of the broadcast station apparatus 31 (step S161), and transmits a notification of participation in the tree type distribution system S2 to the connection destination introduction server 35 (step S162). ). Next, the CPU 311 performs a participation process in the content distributed storage system S1 (step S163). Note that the process of participating in the distributed content storage system S1 in step S163 is the same as the description of step S3 described above with reference to FIG.

  Next, the CPU 311 determines whether there is a request to start or stop broadcasting from the keyboard 3163 or the like by an operation of the broadcast manager or the like (step S164). When there is a request to start or stop broadcasting (step S164; YES), the CPU 311 starts or stops content packet generation processing according to the content of the request (step S165). Next, the CPU 311 determines whether or not the broadcast content data is to be converted (step S166). When the broadcast content data is to be converted (step S166; YES), the CPU 311 as the conversion means broadcasts by a predetermined method. The content data is converted (step S167), and the process proceeds to step S168. If the broadcast content data is not converted in step S166, the process directly proceeds to step S168.

  Next, the CPU 311 determines whether or not the power is turned off (step S168). If the power is not turned off (step S168; NO), the process returns to step S164.

  In step S164, when there is no broadcast start or broadcast stop request (step S164; NO), the CPU 311 establishes connection or disconnects the existing connection from the node device 1 to the downstream in the tree distribution system S2. It is determined whether or not there is a connection disconnection request (step S169). When there is a request for connection establishment or connection disconnection from another node device 1 (step S169; YES), the CPU 311 establishes a connection with another node device 1 or disconnects the connection according to the request (step S169; YES) Next, the distribution of the broadcast content to the node device is started or stopped (step S171), and the process returns to step S168.

  In step S169, if there is no connection establishment or disconnection request from the node device 1 (step S169; NO), the CPU 311 determines whether or not it is time to acquire broadcast content data based on the broadcast program file. Judgment is made (step S172). When it is time to acquire broadcast content data (step S172; YES), the CPU 311 performs broadcast content acquisition processing (step S173), and returns to step S168. Note that the broadcast content acquisition process of step S173 is the same as the description of step S61 described above with reference to FIG.

  Here, when the power is turned off in step S168, it is determined that the power is off (step S168; YES), and the processing in the broadcast station apparatus 31 is ended (END).

  In the present embodiment, it has been described that the acquired first content data is not stored in the hard disk, the content disclosure message is not transmitted for the stored first content data, and the like.

  The broadcast station apparatus 31 mainly participates in the distribution of the second content data in the tree-type distribution system S2, and thus participates in the distributed content storage system S1, but in the system S1, the other node apparatuses 1 It can be set so as not to be stored in the DHT routing table or to be stored by the first content data stored in the content distributed storage system S1 from the content input server 26. In the content distributed storage system S1, when the broadcast station apparatus 31 receives messages and information such as a query, a content disclosure message, and a participation message, processing such as transfer is performed in the same manner as a normal node apparatus.

  Here, in the content distribution system S, there are as many broadcast station devices 31 as the number of broadcast channels, and the broadcast station device 31 of the present embodiment and the normal node device 1 function as the broadcast station device 31. It may be mixed.

[7.2. Second variant]
In the above-described embodiment, when a content packet in the content distributed storage system S1 is received in step S29 in the operation of the node device 1, the content is handled as broadcast content to be distributed (broadcast) in the tree-type distribution system S2. However, the present invention is not limited to this.

  In the second modification, when the node device 1 receives the packet of the first content data, it is determined whether the first content data is content data acquired based on its own request or content data acquired for broadcasting. If it is content data acquired based on its own request, it is stored in the HD of the hard disk device 13 and the content data is reproduced and broadcast for broadcast. Broadcast as content data in the tree-type distribution system S2.

  The operation of the node device 1 according to this modification will be described with reference to FIG. FIG. 29 is a modified example of the flowchart of FIG. 18, and step S similar to FIG. 18 is omitted.

  If the content transmission request information has not been received in step S27 in FIG. 17 (step S27; NO), the process moves to FIG. 29, and the CPU 11 determines whether or not a content packet has been received (step S181). . If no content packet has been received (step S181; NO), the process proceeds to step S44 (not shown in FIG. 29).

  On the other hand, when the content packet is received (step S181; YES), the CPU 11 as the content determination unit distributes the first content data acquired by the CPU 11 as the first content data acquisition unit, that is, the content packet is distributed in a tree form. It is determined whether or not the content data distributed in the system S2 is supported (step S182). Specifically, the CPU 11 determines whether the received content packet is a content packet received as a result of the broadcast content data acquisition process in step S61, or whether the received content packet is included in the broadcast program file. When the content packet is for broadcasting (step S182; YES), the process proceeds to step S30 described above, and processing for broadcasting the content packet is performed (not shown in FIG. 29). At this time, the node device 1 functions as a distribution source node device in the present invention and the broadcast station device 31 in the embodiment, and the CPU 11 functions as a second content data distribution unit.

  In step S182, the received content packet is not a content packet received as a result of the broadcast content data acquisition process in step S61, or the received content packet is not included in the broadcast program file, and the content packet is distributed in tree form. If the system S2 does not correspond to the content data to be distributed (step S182; NO), the CPU 11 determines that the received content data is content data acquired based on its own request, and the first content data is stored on the hard disk. The data is stored in the HD of the device 13 (step S183).

  Next, the CPU 11 reproduces the content data for viewing by the user (step S184), and the content ID information and the location information (such as the IP address of the own node device) of the stored first content data are used as the content index information. (Step S185). Next, the CPU 11 determines whether or not the node device 1 itself becomes a root node when considering the content ID of the first content data (step S186). When the node device 1 itself is not the root node (step S186; NO), the CPU 11 transmits a content release message for the saved first content data to another node device 1 (toward the root node) ( Step S187), the process returns to Step S8 in FIG. On the other hand, if the node device 1 itself is a root node in step S186 (step S186; YES), the process returns to step S8 in FIG. 16 without performing any processing (connector 4).

  In this variation, the node device 1 determines whether or not the first content data acquired by the CPU 11 as the first content data acquisition unit corresponds to content data distributed in the tree distribution system S2. The second content data distribution means when the content determination means determines that the first content data acquired by the first content data acquisition means corresponds to the content data distributed in the tree-type distribution system S2. The CPU 11 may distribute the acquired first content data as the second content data to the other node devices 32 in the tree type distribution system S2. The determination in the content determination means may refer to the broadcast program file as described above for the operation, or may confirm whether or not the content data is received as a result of the broadcast content data acquisition process in step S61. There is no particular limitation.

[7.3. Other variations]
In the above-described embodiment, the content distribution system S includes the contact node introduction server 25, the connection destination introduction server 35, and the content input server 26. However, the present invention is not limited to this configuration. Even if it is not provided, the node device 1 participating in the content distributed storage system S1 and participating in the tree distribution system S2 as the distribution source node device 31 receives the first content data in the content distributed storage system S1. First content data acquisition means (CPU 11) for acquiring first content data from the stored node device 1, and the acquired first content data as second content data to other node devices 32 in the tree-type distribution system S2. Second content data distribution means (C And U11), may have a. Therefore, the operation and role of the devices constituting the system S such as the node device 1 in the content distribution system S may be different due to the absence of the above-described servers.

  Such a content distribution system of the present invention reduces the burden of content storage and the like in the node device that is the content distribution source of the tree distribution system S2. Therefore, even if the broadcast administrator does not separately provide the broadcast station device 31 as in the first modification, the normal user node device 1 plays the role of a broadcast station, so that the operation of the broadcast station can be performed with less equipment. It is possible to reduce the cost for the operation of the broadcasting station.

  In the above-described embodiment, the node device 1 stores the DHT routing table, and the first content data is distributed and stored based on the routing table. However, the present invention is not limited to this embodiment. A content distributed storage system S1 is formed by participation of a plurality of node devices 1, a plurality of first content data is distributed and stored in a plurality of node devices 1, and one node device 1 (the above-mentioned content node) is the other The first content data stored by itself may be transmitted via the communication unit in response to a request from the node device 1.

  In the above-described embodiment, the node device 1 and the broadcasting station device 31 perform the participation process (steps S3, S163, FIG. 20 and the like) in the content distributed storage system S1 when the device starts to be activated. However, it is not limited to this form. For example, the node apparatus 1 participates in the content distributed storage system S1 at a necessary stage such as a stage where the broadcast station apparatus 31 starts to function as the broadcast station apparatus 31 or a stage where the broadcast station apparatus 31 starts distributing the second content data. After obtaining the necessary first content data, the user may withdraw to a necessary stage.

  In the above embodiment, in the description of step S28 and the like, the rate control information is included in any content data (first content data, second (broadcast) content data). However, the present invention is not limited to this. The rate control information may be included only in the second (broadcast) content data.

  In the above-described embodiment, in the description of steps S20, S34, S82 and the like, the content node information of the content data as the cache node is converted into the content index information regardless of whether or not the own node device 1 is the root node. If it is registered but the node device 1 is not the root node (step S21; NO, S35; NO, S83; NO), the content node information of the content data is not registered in the content index information and the next You may proceed to the step.

  In the above embodiment, as shown in FIGS. 5 and 9, the root node notifies the location information of the content node to the node device 1 that is the source of the query, and the node device requests the first content data from the content node. However, the form of acquiring the first content data is not limited to this. For example, when a query transmitted by the node device 1 arrives at the root node, the message that the root node should transmit “corresponding first content data to the node device 1 that transmitted the query” to the content node. The content node that has received this notification may transmit the corresponding first content data to the node device 1 that is the transmission source of the query.

  In the above-described embodiment, the node device 1 can store the first content data acquired for broadcasting in the recording medium (hard disk), and can select whether or not to save. The present invention is not limited, and the first content data acquired for broadcasting may not be stored, or may be stored without selecting whether to store or not.

  In the above-described embodiment, when the node device 1 newly stores the first content data in the recording medium, the public information (indicating that the first content data is stored in another node device) (Content disclosure message) is transmitted to the node device 1 (root node) that manages the location of the first content data in the content distributed storage system S1, and can function as a content node. However, the present invention is not limited to this form, and it may be a form in which the saved first content data cannot be disclosed. It is good also as a form.

  In the above-mentioned embodiment, the acquired first content data is converted into a format for distribution in the tree-type distribution system S2 and converted to the second content data (broadcast content data), and whether to convert is selected. The form that can be done has been explained, but it is not limited to this, it may be a form that does not convert the content data, it is determined that conversion is always performed in a predetermined manner without selecting whether or not conversion is performed, and it is determined that conversion is not necessarily performed It is good also as a form.

  In the above-described content distribution system S, when the tree length in the tree distribution system S2 becomes long (the number of node devices from the distribution source node device to the most downstream node device increases), the distribution is performed. The tree can be divided by increasing the number of original node devices and allowing them to broadcast the same channel (second content data). Thus, the second content data can be distributed more stably without making the tree longer than a predetermined value. For this purpose, the connection destination introduction server 35 can send a message to each node device 1 to adjust the topology of the tree.

  A program corresponding to each operation of the node device 1 or the broadcasting station device 31 is recorded on an information recording medium such as a flexible disk or a hard disk, or acquired and recorded via a network such as the Internet. It is also possible to cause the microcomputer to function as the CPU 11 or the CPU 311 according to each embodiment by reading and executing the above with a microcomputer or the like.

It is a figure which shows an example of the connection aspect of each node apparatus in the content delivery system which concerns on this embodiment. It is a figure explaining ID space by DHT, content ID, and the root node with respect to this. It is a figure which shows an example of a mode that ID space by DHT and a routing table are produced in the content distribution storage system which concerns on this embodiment. (A) An example of a level 1 table. (B) An example of a level 2 table. (C) An example of a level 3 table. (D) An example of a completed routing table. It is a figure explaining ID space by DHT, the search method of content, and the acquisition method. It is a figure explaining ID space by DHT and the disclosure method of the preserve | saved 1st content data. It is a figure explaining ID space by DHT and the participation method of a node apparatus. It is a figure explaining the outline | summary of the tree type delivery system which concerns on this embodiment. It is a figure (1) explaining the outline | summary of the content delivery system which concerns on this embodiment. It is a figure (2) explaining the outline | summary of the content delivery system which concerns on this embodiment. It is a table | surface which shows broadcast station setting information. 2 is a diagram illustrating a schematic configuration example of a node device 1; 3 is a diagram showing an example of a schematic configuration of a contact node introduction server 25. FIG. 3 is a diagram illustrating a schematic configuration example of a connection destination introduction server 35. FIG. FIG. 3 is a diagram showing an example of a schematic configuration of a content input server 26. It is a flowchart which shows the process (1) in the node apparatus 1. It is a flowchart which shows the process (2) in the node apparatus 1. It is a flowchart which shows the process (3) in the node apparatus 1. It is a flowchart which shows the process (4) in the node apparatus 1. 4 is a flowchart illustrating a participation process in a content distributed storage system in the node device 1. 5 is a flowchart showing an input content reception process in the node device 1. 4 is a flowchart showing content search processing in the node device 1. 5 is a flowchart showing broadcast content data acquisition processing in the node device 1. 7 is a flowchart showing processing in the contact node introduction server 25. 5 is a flowchart showing processing in a connection destination introduction server 35. 4 is a flowchart showing processing in the content input server 26. 2 is a diagram illustrating a schematic configuration example of a broadcast station device 31. FIG. 4 is a flowchart showing processing in the broadcast station apparatus 31. It is a flowchart which shows the modification of the process in the node apparatus 1 shown in FIG.

Explanation of symbols

1 Node device 8 Network 9 Overlay network 11 CPU
12 Main Storage Device 13 Hard Disk Device 14 Peripheral Device Control Chip 15 Video Chip 16 Built-in Display 17 Sound Source Chip 18 Built-in Speaker 19 Infrared Port 21 Network Interface 22 System Bus 23 Remote Control for User Input 24 Router S Content Distribution System S1 Content Distributed Storage System S2 Tree distribution system

Claims (14)

A content distributed storage system formed by participation of a plurality of node devices, wherein a plurality of first content data is distributed and stored in a plurality of node devices, and one of the node devices responds to a request from another node device. And the node device participating in the content distributed storage system configured to transmit the first content data stored by itself through communication means, and
A tree-type distribution system formed by participation of a plurality of node devices, wherein the plurality of node devices are connected in a tree shape through communication means while forming a plurality of hierarchies, and distributed from a distribution-source node device The second content data is the node device of the distribution source participating in the tree-type distribution system in which the second content data is sequentially transferred from the node device of the upper layer to the node device of the lower layer,
First content data acquisition means for acquiring the first content data from the node device storing the first content data in the content distributed storage system;
Second content data distribution means for distributing the acquired first content data as the second content data to the other node devices in the tree-type distribution system;
A node device comprising: The node device according to claim 1,
The first content data acquisition means acquires the first content data transmitted by a streaming method,
The second content data distribution means distributes the second content data to the other node devices by a streaming method. The node device according to claim 1 or 2, wherein
The node device further includes a recording medium for storing the received first content data. The node device according to claim 3, wherein
The node device further includes storage determining means for determining whether or not to store the first content data in the recording medium when the first content data is acquired.
The node device, wherein the recording medium newly stores the first content data when the storage determining unit determines to store. The node device according to claim 3 or 4, wherein
When the first content data is newly stored in the recording medium, the node device further stores public information indicating that the first content data is stored in another node device. Public information transmitting means for transmitting to a node device that manages the location of the first content data in the system;
Request receiving means for receiving transmission request information for requesting transmission of the first content data from another node device;
When the request receiving unit receives the transmission request information from another node device, the first content data transmitting unit transmits the first content data stored in the recording medium according to the transmission request information. When,
A node device comprising: The node device according to claim 5, wherein
The node device further includes a disclosure determining unit that determines whether to transmit the disclosure information when the first content data is newly stored in the recording medium,
The public information transmission unit transmits the public information when the public determination unit determines to transmit the public information. The node device according to any one of claims 1 to 6,
The node device further includes search information for searching the location of the node device storing the first content data corresponding to the second content data to be distributed by the second content data distribution means. Search means for transmitting to a node device that manages the location of the first content data in the content distributed storage system;
When node information indicating the location of the first content data is received from the managing node device, transmission request information for requesting transmission of the first content data is transmitted to the node device corresponding to the node information. A request sending means;
Have
The node device characterized in that the first content data acquisition means acquires the first content data from the node device that is the transmission destination of the transmission request information. The node device according to any one of claims 1 to 7,
The node device further includes conversion means for converting the acquired first content data into a format for distribution in a tree-type distribution system to form the second content data,
The second content data distribution unit distributes the second content data after being converted by the conversion unit to another node device. The node device according to claim 8, wherein
The node device according to claim 1, wherein the converting means degrades at least one of video, image, and audio included in the first content data to obtain the second content data. The node device according to claim 8 or 9, wherein
The conversion means selects a part of the video included in the first content data, partially thins out the video included in the first content data, and the size of the video or image included in the first content data A node which reduces at least one of: reducing the quality of a video or image included in the first content data, or degrading the sound quality of audio included in the first content data apparatus. The node device according to any one of claims 1 to 10, wherein
Content determination means for determining whether or not the first content data acquired by the first content data acquisition means corresponds to content data distributed in the tree-type distribution system;
When the content determination unit determines that the first content data acquired by the first content data acquisition unit corresponds to content data distributed in the tree distribution system, the second content data distribution unit A node device that distributes first content data as the second content data to the other node devices in the tree-type distribution system.   An information processing program for causing a computer to function as the node device according to any one of claims 1 to 11. A content distributed storage system formed by participation of a plurality of node devices, wherein a plurality of first content data is distributed and stored in a plurality of node devices, and one of the node devices responds to a request from another node device. And the node device participating in the content distributed storage system configured to transmit the first content data stored by itself through communication means, and
A tree-type distribution system formed by participation of a plurality of node devices, wherein the plurality of node devices are connected in a tree shape through communication means while forming a plurality of hierarchies, and distributed from a distribution-source node device The content distribution method in the distribution source node device participating in the tree-type distribution system in which the second content data is sequentially transferred from the upper layer node device to the lower layer node device. ,
Obtaining the first content data from the node device storing the first content data in the content distributed storage system;
Distributing the acquired first content data as the second content data to the other node devices in the tree-type distribution system;
A content distribution method characterized by comprising: A content distributed storage system formed by participation of a plurality of node devices, wherein a plurality of first content data is distributed and stored in a plurality of node devices, and one of the node devices responds to a request from another node device. In response, the content distributed storage system configured to transmit the first content data stored by itself through communication means, and
A tree-type distribution system formed by participation of a plurality of node devices, wherein the plurality of node devices are connected in a tree shape through communication means while forming a plurality of hierarchies, and distributed from a distribution-source node device A content distribution system comprising: a tree-type distribution system in which the second content data is sequentially transferred from the node device in the upper layer to the node device in the lower layer,
The node device participating in the content distributed storage system and the distribution source node device participating in the tree distribution system are:
First content data acquisition means for acquiring the first content data from the node device storing the first content data in the content distributed storage system;
Second content data distribution means for distributing the acquired first content data as the second content data to the other node devices in the tree-type distribution system;
A content distribution system comprising:

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