JP4715388B2 - Information distribution system, information distribution method, node apparatus included in information distribution system, and information processing program - Google Patents

Description

  The present invention relates to a peer-to-peer (P2P) type information (content) distribution system including a plurality of node devices connected to each other via a network, and in particular, a plurality of node devices are integrated into one node device. The present invention relates to a technical field such as an information (content) distribution system and method that eliminates the inconvenience that lines are congested due to content requests when concentrated requests are made.

  In a peer-to-peer type information distribution system, for example, in an overlay network logically constructed using a distributed hash table (hereinafter referred to as a DHT (Distributed Hash Table)), each node device participates in the overlay network. It does not recognize link information (for example, IP address) to all the node devices, but holds only link information to some node devices obtained at the time of participation. Inquiries about data are made based on the above.

  In such an overlay network, even when node devices frequently participate and leave (leave), load balancing needs to be performed appropriately. Non-Patent Document 1 describes participation and withdrawal in an overlay network. A technique for appropriately distributing load even when (separation) is frequently performed is disclosed.

  In such a peer-to-peer type content distribution system, each node device becomes a content distribution server that holds content data, and each node device also becomes a content distribution request client.

  In such a content distribution system, it is known that not only a node device which is a content distribution server holds content data but also other node devices on the network hold a copy of the content data. . Hereinafter, a node device that holds a copy of content data is also referred to as a replica node. The node device that is a content distribution request client can also obtain the requested content from such a replica node. Such a content distribution system can distribute content not only from a node device that is a content distribution server but also from a replica node device that holds a copy when the number of distribution requests for the content increases. Concentration of access to the node device as a server can be avoided.

Further, as a P2P type content distribution method, a method in a system including a content distribution server, a client device group, and a topology control device that controls connection relation between the server device and the client device is known (patent). Reference 1). In this content distribution method, when the client device inquires of the topology control device for a content acquisition request, the topology control device notifies the client device of identification information of the peer device included in the connection destination candidate, and is indicated by the identification information in the client device. Attempts to connect to the peer device and receives the packet at the client device. In the topology control device, the connection destination candidates are narrowed down and extracted from the peer devices included in the connection destination candidates using a pre-defined selection policy. By this operation of the topology control device, a means for selecting an appropriate connection destination from a server device that transmits information to a certain client device or a client device that can distribute content is provided, and content reproduction is interrupted to the user. , Providing high-quality services that do not cause skipping, reversing, etc.
"Examination of lightweight load balancing method for distributed hash table" The Institute of Electronics, Information and Communication Engineers IEICE technical report JP 2004-246790 A

  In a conventional server-client type content distribution system, access from a client device concentrates on a server device having specific popular content, and stress is applied to the desired content in node devices of a plurality of users who wish to distribute the content. There is an inconvenience that it is difficult to obtain and view it with high quality.

  On the other hand, in the P2P type content distribution system, a node serving as a content distribution server as described above is arranged by arranging a replica node holding a copy of the content in addition to a node device having a specific popular content. Avoids concentration of access to the device.

  However, when the replica nodes are not sufficiently arranged, the same inconvenience as in the conventional server-client type content distribution system is assumed. In other words, there is a high possibility that the quality of the content will deteriorate due to the interruption of communication or the occurrence of an error in the node devices of a plurality of users who wish to distribute the content. Therefore, it becomes difficult for the user to obtain and view the content with high quality without stress.

  In the content distribution method disclosed in Patent Document 1, a technique for controlling a so-called tree-type distribution topology and selecting an appropriate connection destination in P2P type content distribution is disclosed. No technology is disclosed from the viewpoint of avoiding concentration.

  The present invention has been made in view of the above inconveniences, and in a P2P type content distribution system having a plurality of node devices, content obtained by a plurality of node devices concentrating on one node device and requesting content. It is an object of the present invention to provide a content distribution system, method, and the like that eliminate inconveniences such as quality degradation.

In order to solve the above-described problem, the invention according to claim 1 includes a plurality of node devices connected via a network, and content stored in a distributed manner in the plurality of node devices is the plurality of nodes. an information distribution system from node device is delivered to another node device included in the apparatus, the one node device included in the plurality of node devices, the node indicating the node device can transmit the content Request information for requesting transmission of information, request information receiving means for receiving the request information including unique identification information corresponding to the content from the node devices included in the plurality of node devices; A content storage node device that is the node device that stores the specific content among the content that is distributed and stored in the plurality of node devices. And to the node information, and unique identification information corresponding to the content, storage means for storing in association with, if the identification information included in the request information is stored in said storage means, Communication busyness recognition means for recognizing a busyness of communication indicating a degree of local concentration of communication between the content storage node device indicated by the node information corresponding to the identification information included in the request information and another node device; The node information indicating the content receiving node device that is the node device that is receiving the content from the content storage node device indicated by the node information corresponding to the identification information is the content storage node device or the request information. An acquisition method for acquiring from the other node device that similarly stores the node information corresponding to the identification information included in When, wherein when the communication busy degree is out of the predetermined range, as the node information indicating the node streaming node device is a device for streaming the content, the node information acquired by the acquisition unit a streaming node information sending means for sending to said node apparatus of the transmission source of the request information, when the communication busy degree is within a predetermined range, in response to the identification information included in the request information the node information stored in the storage means is an information distribution system characterized by having a content storage node information transmitting means for transmitting to the transmission source of the node device of the request information.

According to this, the user of the requesting node is a source node device of the query (request information), when the query corresponding to the content is transmitted, corresponding to the content ID included in the query (identification information) The root node and the cache node that store the IP address (node information) of the content node (information storage node device) to be distributed can distribute the request destinations where the request node requests the content according to the communication status of the content node. . That is, the root node and the cache node, the communication content node is a locally concentrated manner busy (busy) in the case (outside communication busy degree of a given) are, Oh Ru request node in receiving the content Is the stream type content node ( streaming distribution node device), and the request node is notified of the IP address of the stream type content node as the content request destination node device. On the other hand, when the communication of the content node is not busy (the congestion is within a predetermined range), the root node and the cache node, as usual, set the IP address of the content node as the node device that is the content request destination. To the request node.

Therefore, when the communication of the content node is busy, that is, when access is concentrated on specific popular content, the streaming distribution node information transmission means operates as described above. Distributing the content node will prevent an excessive load on the content node, and it will prevent content quality from degrading due to interruptions in communication or errors at the request nodes of multiple users who wish to distribute content. Is done. As a result, it is possible to obtain and view the desired content with high quality without stress in the node devices of a plurality of users who wish to distribute the content.

In order to solve the above-mentioned problem, the invention according to claim 2 is provided with a plurality of node devices connected via a network, and content stored in a distributed manner in the plurality of node devices is the plurality of nodes. a node information distribution system in the information distribution method to be delivered to another node device from the devices included in the apparatus, said plurality of node devices one node device included in the, capable of transmitting the contents said node a request information for requesting transmission of node information that indicates the device, request information to the request information including the unique identification information corresponding to the content, received from the node device included in the plurality of node devices a receiving step, the one node device, the identification information included in the request information is distributed and stored in the plurality of node devices near point Stored with the node information indicating a content storage node device is the node device that stores the specific content; and unique identification information corresponding to the content, the storage means in association with each in in this case, communication busy to certify communication busy degree indicating a degree of local concentration of the communication with the content storage node device and another node device which the node information indicates that corresponding to the identification information included in the request information The node information indicating the content receiving node device that is the node device that is receiving the content from the content storage node device indicated by the node information corresponding to the identification information. The node corresponding to the identification information included in the content storage node device or the request information An acquisition step of acquiring from the other node device is likewise stored broadcast, the one node device, wherein when the communication busy degree is out of the predetermined range, the node device to stream the content A streaming delivery node information transmitting step for transmitting the node information obtained in the obtaining step to the node device that is a transmission source of the request information, as the node information indicating a streaming delivery node device that is , and the one node When the communication busyness is within a predetermined range , the device uses the node information stored in the storage unit corresponding to the identification information included in the request information as the transmission source of the request information. a information distributing method characterized by comprising: a content storage node information sending step of sending to said node device.

In order to solve the above problem, an invention according to claim 3 is provided with a plurality of node devices connected via a network, and content stored in a distributed manner in the plurality of node devices is the plurality of nodes. a node apparatus in an information distribution system that is delivered from the node device to the other node devices included in the apparatus, the request information for requesting transmission of node information indicating the node device can transmit the content And the request information including unique identification information corresponding to the content is received from the node devices included in the plurality of node devices, and distributed and stored in the plurality of node devices. Node information indicating a content storage node device that is the node device that stores the specific content among the content to be stored; And unique identification information corresponding to Ntsu, storage means for storing in association with each other, the identification information included in the request information, if stored in the storage means is included in the request information the Communication busyness recognition means for recognizing the busyness of communication indicating the degree of local concentration of communication between the content storage node device indicated by the node information corresponding to identification information and another node device, and corresponding to the identification information The node information indicating the content receiving node device that is the node device that is receiving the content from the content storage node device indicated by the node information is included in the content storage node device or the identification information included in the request information. obtaining means for obtaining from a corresponding similarly stores the node information of other node devices, the range communication busy degree of a predetermined If it is outside, as the node information indicating a streaming node device is the node device to stream the content, the node information acquired by the acquisition unit, the node of the transmission source of the request information Streaming distribution node information transmitting means for transmitting to the device, and the node information stored in the storage means corresponding to the identification information included in the request information when the communication busyness is within a predetermined range Content storage node information transmission means for transmitting the request information to the node device that is the transmission source of the request information.

  According to this, a root node and a cache node in an information distribution system that enables a desired content to be obtained and viewed with high quality without stress at request nodes of a plurality of users who desire distribution of the above-described content. Can be provided.

In order to solve the above problem, the invention according to claim 4 is the node device according to claim 3, wherein the communication busyness certifying means is configured to read the content storage node device corresponding to the node information from the content storage node device. The node device is characterized in that the communication busyness level is recognized by receiving communication busyness level information corresponding to the communication busyness level.

  According to this, the root node and the cache node can acquire the communication busyness information directly from the content node, thereby grasping the communication status and distributing the information request destinations of the request nodes at an appropriate timing. Therefore, it is possible to obtain and view the desired content with high quality without stress at request nodes of a plurality of users who wish to distribute the content.

In order to solve the above-mentioned problem, the invention according to claim 5 is the node device according to claim 3 or 4, wherein the streaming distribution node information transmission means is the node information acquired by the acquisition means. the reception status information indicating a reception status of the content in the content receiving in the node device corresponding to the reception status information receiving means for receiving from said content receiving in the node device, based on the reception status information, by the acquisition unit a selection means for selecting the node information indicative of the streaming node device among the node information indicating the acquired content receiving in the node device at least one or more, and the streaming selected by said selection means said node information indicating a distribution node device, the node of the transmission source of the request information A node apparatus and transmits device.

According to this, specifically, of the request node Ru Ah in receiving the content from the content node (content receiver in the node device), the root node good device reception status of the content can be selected. Then, the root node can selected request node (content receiver in the node apparatus) and a stream type contents node informs the stream type contents node to another new request node as a request destination of the content. Therefore, at the request nodes of multiple users who want to distribute content, it is possible to obtain and view the desired content with high quality without stress, especially from a node device (stream type content node) with good content reception status. It becomes. The root node performs an operation of selecting such a stream type content node, and the cache node normally does not perform this operation.

In order to solve the above problem, the invention according to claim 6 is the node device according to any one of claims 3 to 5, wherein the busyness of communication is outside a predetermined range. , the streaming node the node streaming node information transmission instruction information to be transmitted to the device of the transmission source of the request information the node information indicative of the device, corresponding to the identification information included in the request information the A node device characterized by comprising streaming delivery node information transmission instruction information transmission means for transmitting node information to another node device that similarly stores the node information .

According to this, when the root node that has determined the busyness of communication determines that the communication is busy, the other node device (similarly storing the IP address corresponding to the content ID included in the query) Streaming distribution node information transmission instruction information indicating that the IP address of the stream type content node should be transmitted to the request node. Therefore, when a query is received at the cache node, the IP address of the stream type content node can be notified (transmitted) to the request node without transferring the query to the root node, and the request node can quickly transmit the IP of the content request destination. The address can be obtained and the number of communications can be reduced. Therefore, the number of communications in the entire content distribution system can be reduced, and the load on the system is reduced.

In order to solve the above problem, the invention according to claim 7 is the node device according to claim 6, wherein the content storage node device is stored when the busyness of communication is within a predetermined range. Content storage node information transmission instruction information indicating that the node information to be transmitted to the node device that is the transmission source of the request information is stored in the same manner as the node information corresponding to the identification information included in the request information. It is a node device characterized by having content storage node information transmission instruction information transmission means for transmitting to another node device.

According to this, when the root node that has determined the busyness of communication determines that the communication is not busy, the cache node that similarly stores the IP address corresponding to the content ID included in the query, Content storage node information transmission instruction information indicating that an IP address of a normal content node should be transmitted to the request node is transmitted. Therefore, when the query is received at the cache node, the IP address of the normal content node can be notified (transmitted) to the request node without transferring the query to the root node, and the request node can quickly transmit the IP of the content request destination. The address can be obtained and the number of communications can be reduced. Therefore, the number of communications in the entire content distribution system can be reduced, and the load on the system is reduced.

In order to solve the above-mentioned problem, the invention according to claim 8 is the node device according to claim 7, wherein the in- predetermined range report information indicating that the busyness of communication is within a predetermined range, further comprising a predetermined range report information receiving means for receiving from said node device of the destination streaming node information transmission instruction information, when receiving said predetermined range report information, the content storage node information sending device, The node information stored in the storage unit corresponding to the identification information included in the request information is transmitted to the node device that is the transmission source of the request information, and the content storage node information transmission instruction information transmission unit is , Another node device that similarly stores the node information corresponding to the identification information included in the request information in the content storage node information transmission instruction information A node apparatus and transmits.

According to this, when the cache node that has determined the busyness of communication determines that the communication is not busy, the root node or the other node that similarly stores the IP address corresponding to the content ID included in the query. The cache node receives the report information within a predetermined range indicating that the communication is not busy. The root node or other cache node that has received the report information within the predetermined range transmits the IP address of the normal content node to the request node, and transmits the content storage node information transmission instruction information . Therefore, when the cache node first knows that the communication status of the content node is not busy, it reports to the root node and other cache nodes as soon as possible so that a so-called grid mainly composed of normal content nodes Type communication form.

In order to solve the above problems, the invention according to claim 9 is the node device according to claim 7 or 8, wherein the out-of- predetermined range report information indicating that the busyness of communication is out of a predetermined range. further has a predetermined range report information receiving means for receiving from said node apparatus of the transmission destination of the content storage node information transmission instruction information, when receiving said predetermined range report information, the streaming node information transmitter Transmits the node information indicating the streaming distribution node device to the node device that is the transmission source of the request information, and the streaming distribution node information transmission instruction information transmitting means transmits the streaming distribution node information transmission instruction information, be sent to the other node device is similarly stores the node information corresponding to the identification information included in the request information A node apparatus characterized.

According to this, when the cache node that has determined the busyness of communication determines that the communication is busy, the root node or cache node that similarly stores the IP address corresponding to the content ID included in the query. Receives out- of- predetermined range report information indicating that communication is busy. The root node that has received the out-of-predetermined range report information selects the stream type content node, transmits the IP address of the stream type content node to the request node, and transmits the streaming distribution node information transmission instruction information . Therefore, when the cache node first knows that the communication status of the content node is busy, the information request destinations of the request node are quickly distributed to report it to the root node and other cache nodes. It can be changed to a so-called tree type communication form. Then, in the node devices of a plurality of users who wish to distribute the content, it becomes possible to obtain and view the desired content with high quality without stress.

In order to solve the above-described problem, the invention according to claim 10 is the node apparatus according to claim 3 or 4, wherein the node information indicating the streaming distribution node apparatus is the transmission source of the request information. Streaming distribution node information for receiving streaming distribution node information transmission instruction information to be transmitted to the node device from another node device that similarly stores the node information corresponding to the identification information included in the request information A transmission instruction information receiving means , and when the streaming distribution node information transmission instruction information is received, the streaming distribution node information transmission means sends the node information indicating the streaming distribution node device to the transmission source of the request information the node information of the transmitted to the node device, indicating the streaming node device A node apparatus, characterized in that it comprises a transmission completion information transmitting means for transmitting the transmission completion information indicating that the transmission to another of the node device to the source of the node device of said streaming node information transmission instruction information.

According to this, the cache node that has received the streaming distribution node information transmission instruction information from the root node or the cache node transmits the IP address of the stream type content node to the request node to the new request node. Therefore, the cache node can inform (send) the IP address of the stream type content node to the request node without transferring the query to the root node, and the request node can obtain the IP address of the content request destination quickly, The number of communications can also be reduced. Therefore, the number of communications in the entire content distribution system can be reduced, and the load on the system is reduced.

Further, when the cache node receives the streaming distribution node information transmission instruction information , the cache node notifies the request node of the IP address of the stream type content node as a content request destination. In addition, the cache node returns the fact that the stream type content node has been notified to the request node in this way as the transmitted information to the root node that is the transmission source of the streaming distribution node information transmission instruction information . As a result, the root node can select again the stream type content node to be notified to the request node based on the transmitted information, and an appropriate stream type content node with distributed content request destinations can be selected as a new request node. Can be informed.

In order to solve the above-mentioned problem, the invention according to claim 11 is the node device according to claim 10, wherein the node information indicating the content storage node device is used as the node device from which the request information is transmitted. the content storage node information transmission instruction information to be transmitted to the content storage node information transmission instruction received from said another node device is similarly stores the node information corresponding to the identification information included in the request information includes information receiving means, if not received when receiving the content storage node information transmission instruction information and the streaming node information transmission instruction information, the content storage node information sending device, included in the request information The node information stored in the storage means corresponding to the identification information A node apparatus and transmits to the node device.

According to this, when the cache node receives the content storage node information transmission instruction information from the root node or another cache node or when the streaming node information transmission instruction information is not received, the cache node performs a query. , The IP address of the normal content node can be notified (transmitted) to the request node without transferring the query to the root node, and the request node can quickly obtain the IP address of the content request destination and You can also reduce the number. Therefore, the number of communications in the entire content distribution system can be reduced, and the load on the system is reduced.

In order to solve the above-described problem, the invention according to claim 12 is the node device according to claim 10 or 11, wherein the communication busyness is in a case where the communication busyness is within a predetermined range. node but that further comprising a predetermined range report information indicating that the predetermined range, the predetermined range report information transmitting means for transmitting to said node apparatus of the transmission source of the streaming node information transmission instruction information Device.

According to this, when it is determined that the communication node is not busy, the cache node that has determined the communication busyness is busy with the root node or the cache node that is the transmission source of the streaming distribution node information transmission instruction information. The report information within a predetermined range indicating that it has not been transmitted is transmitted. Therefore, the root node or the cache node that has received the report information within the predetermined range transmits the IP address of the normal content node to the request node, or transmits the content storage node information transmission instruction information to another cache node. be able to. Therefore, when the cache node first knows that the communication status of the content node is not busy, it reports so to the root node and other cache nodes, so that a so-called grid that is mainly composed of normal content nodes Type communication form.

In order to solve the above problem, the invention according to claim 13 is the node device according to claim 11, wherein the communication busyness is predetermined when the communication busyness is out of a predetermined range. the range out of the predetermined range report information indicating that the, the node device characterized by further having a predetermined range report information transmitting means for transmitting to the transmission source of the node device of the content storage node information transmission instruction information is there.

According to this, when the cache node that has determined the busyness of communication determines that the communication is busy, it communicates with the root node or other cache node that is the transmission source of the content storage node information transmission instruction information. Send out- of- predetermined report information that is busy. Therefore, the root node that has received the out-of-predetermined range report information can select the stream type content node, and transmits the IP address of the stream type content node to the request node, and the streaming distribution node information transmission instruction information is transmitted. Send. Therefore, when the cache node first knows that the communication status of the content node is busy, the information request destinations of the request node are quickly distributed to report it to the root node and other cache nodes. It can be changed to a so-called tree type communication form. Then, in the node devices of a plurality of users who wish to distribute the content, it becomes possible to obtain and view the desired content with high quality without stress.

In order to solve the above-mentioned problem, the invention according to claim 14 is the node device according to any one of claims 3 to 13, wherein the streaming delivery node information transmitting means is the one streaming delivery. The node device is characterized in that the node information indicating the streaming distribution node device is transmitted to the node device that is a transmission source of the predetermined number or less of the request information to the node device.

  According to this, the root node or the cache node informs the request node of a predetermined number or less of the IP address of one stream type content node. Therefore, a content request is transmitted from a predetermined number or less of request nodes to one stream type content node. Therefore, by distributing content to a large number of request nodes, an excessive load is applied to the stream type content node, and communication is interrupted or an error occurs at request nodes of multiple users who want to distribute content. , Content quality is prevented from deteriorating. As a result, even in the stream type content node, a plurality of users who want to distribute content can obtain and view the desired content with high quality without stress.

In order to solve the above-mentioned problem, an invention according to claim 15 is provided with a plurality of node devices connected via a network, and content stored in a distributed manner in the plurality of node devices is the plurality of nodes. a computer included in a node apparatus in an information distribution system that is delivered from the node device to the other node devices included in the apparatus, the request for requesting the transmission of the node information indicating the node device can transmit the content A request information receiving step for receiving the request information including unique identification information corresponding to the content from the node devices included in the plurality of node devices; and the identification information included in the request information Is the node device that stores the specific content among the content that is distributed and stored in the plurality of node devices. That a content storage node the node information indicative of the device, and unique identification information corresponding to the content, when stored in the storage means for storing in association with the said identification information included in the request information A communication busyness level identifying step for authorizing a communication busyness level indicating a degree of local concentration of communication between the content storage node device indicated by the corresponding node information and another node device; and the node information corresponding to the identification information The node information indicating the content receiving node device that is the node device that is receiving the content from the content storage node device indicated by the information corresponding to the identification information included in the content storage node device or the request information an acquisition step of acquiring from the other node device is likewise stored node information, the communication Shigeru Degrees when it is out of the predetermined range, as the node information indicative of the streaming node device is a node device to stream the content, the node information obtained in the obtaining step, said request information A streaming distribution node information transmission step for transmitting to the node device that is a transmission source, and when the communication busyness is within a predetermined range, the storage means stores the identification information included in the request information. And a content storage node information transmission step of transmitting the node information thus transmitted to the node device that is the transmission source of the request information.
In order to solve the above-described problem, an invention according to claim 16 is the information distribution system according to claim 1, wherein the node information is transmitted from the streaming distribution node information transmission unit. The streaming delivery node device authorization unit that authorizes the node device that is the transmission source of the request information as the new streaming delivery node device, the node information transmitted from the streaming delivery node information transmission unit, and the authorization unit And second storage means for storing the node information indicating the node apparatus authorized as a streaming distribution node apparatus in association with each other, wherein the streaming distribution node information transmission means is stored in the second storage means. Each of the streaming distributions based on the node information stored in association with each other Selection means for selecting the node information to be transmitted so that the content is sequentially transferred by a node device, and the streaming distribution node information transmission means includes the node information selected by the selection means, The information distribution system transmits the request information to the node device that is the transmission source of the request information.
In order to solve the above problem, an invention according to claim 17 is the information distribution system according to claim 16, wherein the selection unit is configured such that a distribution route of the content is a tree by a plurality of streaming distribution node devices. The information distribution system is characterized in that the node information to be transmitted is selected so as to be formed in a shape.
In order to solve the above problem, an invention according to claim 18 is the information distribution system according to any one of claims 1, 16, and 17, wherein the node device that is the transmission source of the request information is When the node information indicating the streaming distribution node device or the content storage node device is received, the content request information requesting transmission of the content is transmitted to the node device corresponding to the received node information. Content streaming information transmission means, wherein the streaming distribution node device or the content storage node device that has received the content request information transmits the content to a node device that is the transmission source of the content request information. And an information distribution system characterized by comprising:
In order to solve the above-mentioned problem, an invention according to claim 19 is the node device according to any one of claims 3 to 14, wherein the node information transmitted from the streaming distribution node information transmitting means. A streaming delivery node device certifying unit that authorizes the node device that is the transmission destination of the request information as a new streaming delivery node device, and the node information transmitted from the streaming delivery node information sending unit. A second storage unit that associates and stores the node information indicating the node device that has been certified as the streaming delivery node device by the authorization unit, and the streaming delivery node information transmission unit includes: Each of the scans is based on the node information stored in association with the second storage means. Selection means for selecting the node information to be transmitted so that the content is sequentially transferred by a reaming distribution node device, and the streaming distribution node information transmission means includes the node information selected by the selection means; The node device transmits the request information to the node device that is the transmission source of the request information.
In order to solve the above problem, an invention according to claim 20 is the node device according to claim 19, wherein the selection unit is configured such that a distribution route of the content is a tree shape by a plurality of streaming distribution node devices. The node device is characterized in that the node information to be transmitted is selected so as to be formed.

  ADVANTAGE OF THE INVENTION According to this invention, in the node apparatus of the some user who desires distribution of a content, it becomes possible to obtain and view desired content with high quality without stress.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the best embodiment of the invention will be described based on the drawings. The embodiment described below is an embodiment when the information to be distributed is content information and the present invention is applied to a content distribution system.

[1. Content distribution system configuration]
First, with reference to FIG. 1, a schematic configuration and the like of a content distribution system as an information distribution system will be described.

  FIG. 1 is a diagram illustrating an example of a connection mode of each node device in the content distribution system 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 (node information in the present invention). Yes. 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.

[1.1. Outline of DHT]
Hereinafter, an algorithm using a distributed hash table (hereinafter referred to as DHT (Distributed Hash Table)) according to 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 using the existing network 8.

  In the present embodiment, an overlay network 9 constructed by an algorithm using DHT is assumed, and a node device 1 arranged on the overlay network 9 participates in the content distribution system S (in other words, the overlay network 9 The node device 1 participating in the network. Participation in the content distribution system S is performed when a node device that has not yet participated sends a participation request to an arbitrary node device 1 that has already participated.

  The node ID (identification information) of each node device 1 participating in the content distribution system S 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 nodes that can be operated. For example, if the number is 128 bits, 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 serial 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 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.

  In addition, content (for example, movies, music, etc.) data as shared information distributed from one node device 1 to another node device 1 is distributed to a plurality of node devices 1 participating in the content distribution system S. However, a unique number (hereinafter referred to as a content ID (identification information of the present invention)) is assigned to 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 content data stores the link data (IP address of the content storage node) to the node device that stores the content data. As a result, the content data can be distributed on the content distribution system S without any bias. Note that even if the content data is different, it is assumed that the same keyword (for example, the name of the content) is used. In this case, the hash value is the same to avoid the same hash value. The keyword may be, for example, a combination of 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 the content ID assigned to each node device 1 and each content data are generated by a common hash function, as shown in FIG. 2, there is no significant bias on the same ring-shaped ID space. 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 content data is stored in which node device 1 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 content data is managed by each node device 1. It is only necessary to be consistent when allocating. In the example shown in the figure, based on this definition, the content IDa is managed by the node device having the node IDa, the content IDb is managed by the node device having the node IDb, and the content IDc is the node having the node IDc. Managed by the device 1.

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

[1.2. 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 ID of the node device 1N is “10230210” and the routing table of the node device 1N is created will be described.

(Level 1 routing)
First, if the ID space is divided into four areas, each area is expressed in four numbers 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 indicates 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.

[1.3. Content data search method]
Next, an example of a search method for the node device 1 that is a storage source of content data will be described with reference to FIG.

  FIG. 5 is a diagram illustrating an example of a state in which the node device 1 that is a storage source of content data is searched by DHT.

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

  The request node refers to the level 1 table of the routing table held by itself, and requests information (hereinafter, referred to as the location of the content) to the node device having the node ID of the same area as the content ID “31330012”. “Request information” (request information for inquiring about the location of content) of the present invention is referred to as “query”). That is, since the content ID “31330012” is an 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 (which stores the address). 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 having 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.

  As described above, when the transfer of the query proceeds in the manner of adapting the digit of the content ID from the top and finally reaches the node device 1-5 that manages the content data, that is, the root node, the root node Retrieves the content ID “31330012” included in the query from index information (described later) managed by itself, and uses the IP address of the node device 1 that owns the content data as the request node. It comes to reply.

  Thus, the request node (node device 1-1) receives the location of the content data with the content ID “31330012” from the root node (node device 1-5), that is, the IP address of the node device 1 that is the storage source. Therefore, the content data is acquired (downloaded) from the node device 1 that is the storage source.

[1.4. How to register content data]
In the content distribution system S having such a configuration, for example, a method when a certain node device 1 publishes new content data so that it can be seen by other node devices on the content distribution system S will be described. This node device 1 becomes a content node as an information storage node device that holds (stores) content data.

  The content node obtains a content ID from the content title and the like, and transmits a public message to a node device having the same node ID as the content ID (whether or not this node device actually exists at this point). To do. Then, the public message is also transferred one after another according to the routing table in the same manner as the above query, and when the node message 1 is transferred to the node device 1 having the node ID closest to the content ID included in the public message, the node device 1 determines that there is no other destination node device, it determines that the node device 1 itself should be the root node of the content, and the content ID, auxiliary information (attribute information such as title and genre, , Copyright information such as a director name) and the IP address of the content node are stored as index information.

  Furthermore, in the present embodiment, a node device in the middle of the route to the root node is provided with a cache node that holds index information stored in the root node as a cache. Thereby, before the root node receives the query, the cache node may 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 device earlier. It becomes possible.

  When transferring a public message, the cache node normally holds only index information as described above. On the other hand, in the embodiment described later, as shown in FIG. 6, each cache node holds index information as well as the cache node holding its own IP address and index information in front of it as shown in FIG. The IP address is transferred to the next cache node or root node together with the index information.

  Therefore, in FIG. 6, when the content node transmits a public message including index information, the node device 1 that has received the message functions as a cache node (1) by holding the index information. Then, the cache node (1) adds its own IP address information to the public message and transfers it. The node device 1 that has received the public message functions as a cache node (2) by holding the index information and the IP address information of the cache node (1). Then, the cache node (2) further adds its own IP address information to the public message to which the IP address information of the cache node (1) is added, and transfers the message. The node device 1 that has received the public message functions as a root node by holding the index information and the IP address information of the cache nodes (1) and (2). In FIG. 6, the two node devices between the content node and the root node function as cache nodes. However, the present invention is not limited to this, and the number of cache nodes and all transferred node devices are cached. Whether or not to be a node or the like can be freely determined in the content distribution system S.

[2. Node device configuration]
Next, the configuration and function of the node device 1 will be described with reference to FIG. Note that each node device 1 is a request node that transmits a query for inquiring about the location of content by a process performed by each node, a cache node or a root node that receives a query from the request node or a terminal on a route, and a target of an inquiry by a request node. A content node as an information storage node device that holds the content, and a stream type content node (request node) as an information partial storage node device that is downloading (distributing) the content and partially storing the content The structure is the same.

  FIG. 7 is a diagram illustrating a schematic configuration example of the node device 1.

  As shown in FIG. 7, each node device 1 includes a control unit 11 as a computer including a CPU having a calculation function, a working RAM, a ROM for storing various data and programs, the content data, and the index. The storage unit 12 (the content data may be stored in the node device 1 is not stored) as a storage unit composed of HD or the like for storing and storing (storing) information, the DHT, the program, and the like. A buffer memory 13 for temporarily storing content data; a decoder unit 14 for decoding (data expansion, decoding, etc.) encoded video data (video information) and audio data (audio information) included in the content data; The decoded video data is subjected to a predetermined drawing process to A video processing unit 15 that outputs the video signal, a display unit 16 such as a CRT or a liquid crystal display that displays video based on the video signal output from the video processing unit 15, and D (Digital ) / A (Analog) converted and then amplified and output by an amplifier, a speaker 18 that outputs an audio signal output from the audio processor 17 as a sound wave, and other nodes through the network 8 A communication unit 20 for controlling communication of information with the apparatus 1 and an input unit (for example, a keyboard, a mouse, or the like) that receives an instruction from the user and gives an instruction signal corresponding to the instruction to the control unit 11 , Operation panel, etc.) 21, control unit 11, storage unit 12, buffer memory 13, decoder unit 1 And the communication unit 20 are connected to each other via a bus 22.

  Then, the CPU in the control unit 11 executes various programs stored in the storage unit 12 and the like so as to control the entire node device 1, and according to an instruction signal from the input unit 21. The content data registration process is performed. Depending on the program to be executed, the node device 1 is a request node, a cache node, a root node, a content node as an information storage node device, a stream type content node as an information partial storage node device (content distribution (receiving)) It functions as a node being downloaded as a node device).

  Specifically, when the node device 1 functions as a request node, the control unit 11 functions as request information (query) transmission means for inquiring about the location of content, and shared information (content) request information transmission means. . When the node device 1 functions as a cache node or a root node, the control unit 11 includes storage means, request information reception means, communication busyness recognition means, information partial storage node information transmission means, information storage node information transmission means. , Function as.

  In addition, when the node device 1 functions as a root node, the control unit 11 performs the distribution node information receiving unit, the reception status information receiving unit, the selecting unit, the busy communication instruction information transmitting unit, and the non-communication busy instruction. It functions as information transmission means, non-communication busy report information receiving means, and communication busy report information receiving means. When the node device 1 functions as a cache node, the control unit 11 includes communication busy instruction information receiving means, transmitted information transmitting means, non-communication busy instruction information receiving means, and non-communication busy report information transmitting means. It functions as a communication information reporting means during busy communication. When the node device 1 functions as a content node (information storage node device) or a stream type content node (information partial storage node device), the control unit 11 functions as a shared information request information receiving unit and a shared information transmitting unit. To do.

[3. Outline of content distribution system]
An outline of the content distribution system S of the present embodiment will be described. In the overlay network 9 (so-called grid type network) as shown in the upper frame 100 of FIG. 1 and the upper frame 100 of FIG. 8, a plurality of node devices (for example, 1a, 1d, 1e, 1f, 1j, 1z ( 8) when the content data is concentrated on one node device (for example, 1h (shown by a grid line)) having specific content data and the content data is downloaded. As shown in the figure, content request destinations of request nodes are distributed.

  That is, in the content distribution system S of the present embodiment, communication concentrates on content nodes having specific popular content data (in a time shorter than the time when content is stored in a replica node and a copy is made). When a large number of requests are generated, access is locally concentrated on a specific content node), and the so-called grid-type communication mode is changed to a so-called tree-type communication mode. Specifically, as shown in an upper frame 100 and a lower frame 102 in FIG. 8, a request is made from the one content node device 1h having specific popular content in the past to become a request node, and the content is downloaded. Then, there are other node devices 1e and 1z (hereinafter referred to as “nodes being downloaded”) that hold a part of them. Then, the node node 1a, 1d, 1z, and other node devices 1a, 1d, 1f, and 1j that have newly become request nodes download the content data, and the root node manages the details as will be described later. It is.

  In this way, the above-described downloading nodes 1e and 1z receive the content from the node device 1h and distribute the received content to other node devices one after another, and the content is streamed and distributed. Therefore, such node devices 1e and 1z are referred to as “stream type content nodes” in the present embodiment.

  By distributing the content request destinations of request nodes in this way, it is possible to prevent concentration of communication to node devices that hold popular content, and to prevent deterioration in the quality of content information such as communication being interrupted. The user of the node device that requests information can view the content information without stress.

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

[3.1.1. Operation of the entire content distribution system]
First, the operation of the entire content distribution system S will be described with reference to FIG. 9 to FIG. FIG. 9 and FIG. 10 are diagrams for explaining the operation when the root node selects a stream type content node. 11 to 14 are sequence charts among the request node, the root node, the content node, the node being downloaded, the stream type content node, and the cache node when the request node inquires about the location of the content node that holds the desired content data. is there.

(1) When the communication status of the content node is busy (congested) First, the operation when the communication status of the content node is busy (congested) will be described with reference to FIGS. In addition, the above-mentioned drawing is referred as needed.

  As a premise of this operation, as shown in FIGS. 6, 9 and 10, the content ID (identification information) of the content requested by the request node is “30210113”, and the IP address of the content node storing this content ( Node information) is “100.23.156.1”.

  First, FIG. 9 and FIG. 10 will be described. FIG. 9A is an information table created when the root node selects a stream type content node from a plurality of request nodes, and the stream type content node created at the moment when communication of the content node starts to become busy. An information table is shown. FIG. 9B corresponds to the information table of FIG. 9A, and the access from the request node is concentrated on the content node and the communication of the content node starts to be busy (or the communication is busy). It is a schematic diagram which shows the content delivery form of (just before starting).

  FIG. 10 (A) is an update of the information table of FIG. 9 (A). After the content node communication starts to become busy, the stream type content node created including the additional request nodes is shown. An information table is shown. FIG. 10B is a schematic diagram showing a tree-type content distribution form in which stream-type content nodes are created, corresponding to the information table of FIG.

  As shown in FIG. 9B, when access from the request node concentrates on the content node, the root node indicates that the communication busyness of the content node is out of a predetermined range (local concentration occurs). As shown in FIG. 9A, an information table for selecting a stream type content node from a plurality of request nodes is created. This information table is created for each content node managed by the root node and stored in the storage unit 12 of the root node. In the case where IP addresses of a plurality of content nodes are stored, a plurality of information tables are created.

  When the root node starts creating the information table of the stream type content node, as shown in FIG. 9A, as the node information being downloaded (node information being distributed), the node ID, IP address, Get the query transmission date and time information of each downloading node. In FIG. 9A to FIG. 10B, node numbers <1> to <7> are temporarily assigned to the respective nodes being downloaded.

  Next, as shown in FIG. 9A, the root node receives information such as DL (download) start date and time, the number of HOPs with the DL (download) source, DL (download) status, and assumed effective bandwidth as reception status information. To get. When the root node receives a query from the new request node when the content node is busy (communication busy is out of a predetermined range), the environment evaluation value is used as information for selecting stream-type content from the reception status information. , Determine (estimate) the number of DL (downloadable) devices, the number of devices during DL (downloading), and the like. Information such as the environmental evaluation value, the number of DL-capable devices, and the number of devices in the DL is used as distribution capability information.

  Next, as shown in FIG. 10A, the root node refers to the distribution capability information, and DL (download) to be introduced to a new request node (node devices of node numbers <4> to <7>). The original IP address is determined, and this IP address is returned as a response to the query from the new request node. At this time, as will be described later, the node device 1 corresponding to the DL source IP address notified to the new request node may be inquired of other node devices 1 as to whether the content can be downloaded. Information such as the IP address of the device in the DL as the topology information, the number of stages in the tree, and the like are determined according to the stream type content node from which the request node receives the content. From the topology information shown in FIG. 10A, a tree-type distribution form as shown in FIG. 10B is grasped. Then, after the state of FIG. 10B, a new request node is connected to the node device 1 with the node number <5> or <7> (refer to the broken line arrow and the oval column in FIG. 10B). Content will be distributed.

  Here, each information in the information table of FIG. 9 (A) and FIG. 10 (A) is demonstrated.

  The query transmission date and time indicates the date and time when the downloading node transmits the query, and the download start date and time indicates the date and time when the downloading node starts downloading.

  The number of HOPs with the download source indicates the number of hops from the downloading node to the content node that is the download source, and this hop number is the amount of decrease in the TTL field in the IP packet when the downloading node exchanges with the content node. Etc. The smaller the number of hops, the closer is the node being downloaded to the content node, indicating that the receiving status of the node being downloaded is better.

  The download status indicates the ratio of the downloaded content in the node being downloaded. The closer the download status is to 100%, the closer the reception of the content being downloaded is to the end. When the request node downloads content from the node device 1 (stream type content node) whose download status is close to 100%, the probability that the content data can be received without interruption is increased. Therefore, depending on the policy for selecting a stream type content node, which will be described later, when the root node selects a stream type content node that responds to the request node, the priority of the node device 1 whose download status is close to 100% You can select by raising the ranking.

  The assumed effective bandwidth represents the communication speed assumed in the node being downloaded in units of bps (bit per second), and the larger the size, the better the reception status of the node being downloaded. The assumed effective bandwidth may be obtained directly from the node being downloaded, or may be calculated by the root node from the download start date and time and the download status described above. In the present embodiment, it is assumed that the assumed effective bandwidth is obtained directly from the node being downloaded, and when information on the assumed effective bandwidth is not obtained, such as the node being downloaded does not recognize the assumed effective bandwidth, FIG. The node numbers <4> and <6> in (A) are indicated as unknown.

  The environment evaluation value is a value obtained by evaluating the communication environment of the node being downloaded. In the present embodiment, A is the best and D and unknown are the least. The environmental evaluation value is calculated from at least one of the number of HOPs with the download source, the download status, the assumed effective bandwidth, and the like. In the present embodiment, the environmental evaluation value is calculated only from the assumed effective bandwidth, the assumed effective bandwidth is 20 Mbps or more, the environmental evaluation value A, the assumed effective bandwidth is 10 Mbps or more and less than 20 Mbps, the environmental evaluation value B, and the assumed effective bandwidth is 5 Mbps or more and less than 10 Mbps. The environmental evaluation value C and the assumed effective bandwidth of less than 5 Mbps are set as the environmental evaluation value D, and the environmental evaluation value of the unknown effective bandwidth (unknown) is also unknown.

  The number of downloadable devices indicates the number of devices that can be downloaded simultaneously from one node device 1, and is estimated according to the environmental evaluation value. In this embodiment, the number of downloadable devices is as follows: environmental evaluation value A: 4 units, environmental evaluation value B: 2 units, environmental evaluation value C: 1 unit, environmental evaluation value D and environmental evaluation value unknown: 0 unit Yes. The downloading node with one or more downloadable devices is a node device that is certified as a stream type content node, and the downloading node with zero downloadable devices is a node that is not certified as a stream type content node Device. In this way, the root node selects one or more downloadable nodes having a good network environment as devices capable of distributing content to other node devices.

  The number of devices being downloaded indicates the number of node devices that are actually downloading content from the corresponding node device at the present time. It is managed in the root node so that the number of devices being downloaded does not exceed the number of downloadable devices. At the start of creating the information table, the number of devices being downloaded is zero as shown in FIG. 9A, but in FIG. 10A after the number of request nodes has increased, the node number <1 > Downloading from the node device being downloaded, one request node being downloaded from the node device being downloaded at node number <2>, two request nodes being downloaded from the node device being downloaded at node number <5> There is one request node.

  The DL source IP address is node information indicating which node device the node device 1 directly downloads content data from. That is, the DL source IP address can be said to be link information directed upstream in the tree-type distribution form of the node device 1. When communication is not busy (communication busyness is within a predetermined range), the download source IP address is the IP address “100.23.156.1” of the content node managed by the root node.

  The IP address of the device in the DL is information indicating to which node device 1 content is distributed from the node device 1 toward the downstream of the tree-type distribution form. That is, the IP address of the device in the DL can be said to be link information directed downstream in the tree-type distribution form of the node device 1. Since content may be distributed from one node device to a plurality of node devices, the IP address of the device in the DL is a plurality of IP addresses like the node device of node number <2> in FIG. As a list of

  The number of stages in the tree is a number indicating the stage number of the node device 1 in the tree-type distribution form. The number of stages in the tree is referred to when determining which branch (node device 1) should be connected to the new request node when a new request node is added to the tree-type distribution form. .

  From these pieces of topology information (DL source IP address, IP address of the device in the DL, and three pieces of information in the tree), the topology of the tree-type distribution form can be grasped.

  Note that the information table in FIG. 9A shows information at the time when communication starts to be busy, so the DL source IP addresses are all node devices 1 (node numbers <1> to <3>). 1 shows the IP address “100.23.156.1” of the content node. Thereafter, new request nodes for the content to which the query has been transmitted are sequentially managed in the lower column of the information table in FIG. 9A. For example, the node number <4> added in FIG. As a result of managing the node device 1 so as to connect to the node device with the node number <1>, the DL source IP address of the <A> node device is that of the node device with the node number <1> that is a stream type content node. The IP address is “205.60.222.23”. In other words, when the node device with the node number <4> issues a query, the root node returns the IP address of the node device with the node number <1> as a response to the query. As a result, the information in FIG. The table and the tree-type distribution form shown in FIG.

  Thus, the root node holds an information table so that topology information in a tree-type distribution form can be managed. In other words, the root node knows all the information about which node is downloading the content from which node, and when a new request node appears, it can introduce where to connect in the distribution tree. .

  Here, various types of information such as topology information in the information tables shown in FIGS. 9A and 10A are not limited to this, and can be changed according to the embodiment. For example, the storage variables indicating each node device are connected with a pointer, and a memory such as (0 (1 (4)) (2 (5 (7)) (6)) (3)) is used using the LISP S expression. It is good as a form.

  Further, when another request node appears, the root node selects a stream type content node so as to be connected to the position represented by the broken line in FIG. 10B, and sets the IP address of the node device 1 as Reply as query response. In this example, there are two connection candidates of the node numbers <5> and <7>, but various policies can be considered as to how to select them, and various methods are possible.

  For example, if the policy is to grow the tree in a balanced manner as much as possible, in order from the node with the smallest number of stages in the tree, nodes with a margin in the number of DLs (the difference between the number of DL capable devices and the number of devices in DL is 1 or more Node). If the tree balance is not good, an extremely long branch is formed, and if the node device 1 included in the branch is withdrawn, many downstream node devices 1 are affected. In the example of FIG. 9 and FIG. 10, when the node <6> queries, the downstream of <5> should have been vacant, but the result of introducing <2> with a lower number of stages preferentially, They are connected as shown in FIGS. 10 (A) and 10 (B). Alternatively, in the policy that each node device 1 wants to share the load as evenly as possible, it is preferable to select the node with the most allowance from the nodes with the sufficient number of DLs. Alternatively, if the policy is to avoid playback interruption during streaming as much as possible, a node with a DL status as close to 100% as possible should be selected.

  Note that in the “stream type content node information table managed by the root node” shown in FIG. 9A, when the time further advances, the download type is completed (the download status is 100%). Stream type content node certification, such as deleting a node and managing it as a new content node (replica node) or adding information to manage which request node is downloading from which stream type content node Can be updated. Further, as described later, when the communication status of the content node is not busy, the “stream type content node information table managed by the root node” shown in FIGS. 9A and 10A is stored in the root node. It is deleted in part 12. The form in which the information table is deleted will be described in detail in step S57 in FIG.

  Next, the operation of the system S when the communication status of the content node is busy (congested) will be described with reference to FIG. As shown in FIG. 11, when the request node transmits a query (including the content ID “30210113”), the query is transferred to the root node via an intermediate node in some cases (1). According to the example illustrated in FIG. 5, the node device 1-1 is a request node, the node devices 1-2, 1-3, and 1-4 are intermediate nodes, and the node device 1-5 is a root node.

  The root node that has received the query searches the content ID included in the query from the index information managed (stored) by itself, and as shown in FIG. 6, the content ID “30210113” and the content corresponding thereto Since the node IP address “100.23.156.1” is stored, the content node is inquired about the busyness of communication (2).

  Then, the content node recognizes its own communication busyness, and transmits corresponding communication busyness information to the root node (3). Specifically, as shown in FIGS. 9A and 9B, the content node transmits communication busyness information indicating that content is currently being distributed to three node devices. Note that the content node may transmit information to the root node that the busyness of communication is out of a predetermined range at this time.

  Next, when the route node determines that the communication busyness corresponding to the received communication busyness information is outside the predetermined range, that is, the content node is very busy (4), the root node determines the content request destination of the request node. In order to distribute, the content node is inquired of the node device (indicating the above-mentioned downloading node) that is delivering (receiving) the content (5).

  Then, the content node confirms the node being downloaded (6), and transmits node information (IP address: see FIG. 9A) corresponding to each of these node devices to the root node (7). Next, the root node starts creating a stream type content node information table as shown in FIG. 9A based on the received node information being delivered (8), and the node being downloaded corresponding to the received IP address (The request node at this time) is inquired about the content reception status (query date, download start date, number of HOPs with the download source, download status, assumed effective bandwidth, etc.) (9). The downloading node inquired about the content reception status transmits reception status information (see FIG. 9A) indicating the reception status to the possible extent to the root node (10). Note that “possible range” indicates that the reception status information is not sent until the node being downloaded does not recognize the reception status of the content, for example, as shown in FIG. Thus, if the assumed effective bandwidth cannot be obtained from the node devices 1 with the node numbers <4> and <6>, the root node recognizes “unknown”.

  As shown in FIG. 9A, the root node that has received the reception status information from the node being downloaded creates information for selecting a stream type content node, as shown in FIG. 9A. Specifically, as described above with reference to FIG. 9A, the environmental evaluation value, the number of downloadable devices, the number of devices being downloaded, the download source IP address, the IP address list of the node device 1 being downloaded, Determine the number of stages in the tree. At this stage, since the process for determining the stream type content node is performed, the download source IP address at this point is the IP address of the content node, and the list of IP addresses being downloaded is empty. The number of devices being downloaded is 0 (zero).

  The root node stores the node information being distributed, the reception status information, and information for selecting the stream type content node as a “stream type content node information table” (FIG. 9A).

  The root node then selects one or more node devices (for example, the node devices 1 with the node numbers <1> and <2>) selected as the distributing node device that can distribute the content to other devices based on the environmental evaluation value. An inquiry is made as to whether content information can be distributed (11). Here, if the number of DL-capable devices estimated by the root node is highly accurate, this inquiry may be omitted. Or conversely, when only an estimation with low accuracy can be performed, the information table may not have an environmental evaluation value.

  When the downloading node inquired in this way transmits to the root node that content information distribution is possible (12), the root node recognizes the node device as a stream type content node (13). Then, the root node selects a node device that informs (transmits) the IP address to the requesting node from among the node devices recognized as the stream type content node. The method of selecting the stream type content node is as described in the above topology information.

  The root node uses the IP address of the selected stream type content node as a content request destination, and transmits it to the request node as a reply to the query (14). Note that the root node assigns the IP address of the stream type content node to a request node (a node device that transmitted the query) that is equal to or less than a predetermined number (the number of downloadable devices described above) for one stream type content node. It is preferable to transmit. As a result, the communication status of the stream type content node is congested, and it is possible to prevent the quality of the content from being lowered due to the communication being interrupted or an error occurring. As a result, it is possible to obtain and view the desired content with high quality without stress in the node devices of a plurality of users who wish to distribute the content.

  The request node that receives the IP address of the content request destination transmits a content request (shared information request information of the present invention) to the stream type content node corresponding to the IP address (15). Upon receiving the content request, the stream type content node starts distributing the content to the request node that has transmitted the content request (16). In this way, the content distribution system S temporarily becomes a so-called tree-type communication form as shown in FIG. 10B, and the communication congestion at the content node is alleviated. When a new request node starts downloading content from the stream type content node, the root node increases the number of node devices 1 shown in FIGS. 9A and 10A, and distribution capability information, topology information, Update the DL status etc. of the reception status information.

  Further, when the root node selects the stream type content node (13), the root node caches the busy communication instruction information indicating that the IP address indicating the stream type content node should be transmitted to the request source node of the query. Transmit to the node (17). At this time, as shown in FIG. 6, since the IP address of the cache node is transferred to the root node when the public message of the content node is transferred, the root node corresponds to the IP address. The communication busy instruction information is transmitted to all the cache nodes.

  Thereafter, when the request node transmits a query and the query is transferred to the cache node via the intermediate node (18), the cache node indicates the IP address indicating the stream type content node as the content request destination, and the source of the query (19).

  The request node that receives the IP address of the content request destination transmits a content request to the stream type content node corresponding to the IP address (20). Upon receiving the content request, the stream type content node starts distributing the content to the request node that has transmitted the content request (21).

  Next, another operation of the system S when the communication status of the content node is busy (congested) will be described with reference to FIG. FIG. 12 shows that the cache node inquires of the content node about the communication busyness before the root node, and the communication busyness corresponding to the received communication busyness information is out of a predetermined range, that is, the content node is very crowded. Operation when it is determined that In the following description, the same matters as those described with reference to FIG. 11 are omitted.

  As shown in FIG. 12, when a request node transmits a query, the query is transferred to a cache node via an intermediate node in some cases (31).

  Upon receiving the query, the cache node searches the index information managed (stored) for the content ID included in the query, determines that it is the cache node, and communicates with the content node. Inquires about busyness (32).

  Then, the content node recognizes its own communication busyness and transmits communication busyness information corresponding to this to the cache node (33). If the cache node determines that the communication busy level corresponding to the received communication busy level information is out of the predetermined range, that is, the content node is very busy (34), the communication busy level is out of the predetermined range. The communication busy time report information to the effect is transmitted to the root node (35). When the cache node transmits the busy communication report information to the root node, the query is transmitted in the same procedure as when the query is transferred.

  Then, in the root node, a stream type content node information table is created (36 to 36) in the same manner as (4 to 13) when it is determined that the communication busyness shown in FIG. 44) The node device to be a stream type content node is selected, and the communication busy instruction information similar to the above (17) is transmitted to the cache node (45).

  Then, the cache node transmits the IP address of the instructed stream type content node as the content request destination to the request node (46).

  The request node that receives the IP address of the content request destination transmits a content request to the stream type content node corresponding to the IP address (47). Upon receiving the content request, the stream type content node starts distributing the content to the request node that has transmitted the content request (48).

  On the other hand, when the cache node transmits the IP address of the instructed stream type content node to the request node as a content request destination (46), the cache node transmits transmitted information indicating that to the root node (49).

  The root node that has received the transmitted information updates the stream type content node information table in consideration of the fact that one request node is downloading content from the stream type content node corresponding to the IP address (50). . Here, the number of devices being downloaded, information on the IP address of the device being downloaded, etc. are updated, and the node device 1 participating in the tree-type communication form is newly registered in the information table as a stream-type content node. The topology information in the tree-type communication form is updated.

  Regarding the update of the information table, when the request node actually starts to receive data from the content node instead of updating the topology information when the cache node responds to the query from the request node as described above. More preferably, the information table is updated. In this case, when there is a request node that transmits only the query and does not actually start downloading the content, the root node can hold the information table more accurately. In the case of such a form, instead of the processing of (49) in FIG. 12, report information indicating that “downloading of content from a certain stream type content node has started” is transmitted from the request node to the root node. Will do.

  In this way, the cache node informs the request node of the stream type content node in the same way as the root node, so that the query is concentrated and transferred to the root node particularly when there are a plurality of node devices holding the content data. It is possible to prevent the processing from being delayed at the root node.

(2) When the communication status of the content node is not busy (congested) Next, the operation when the communication status of the content node is not busy (congested) will be described with reference to FIGS. In addition, the above-mentioned drawing is referred as needed.

  As shown in FIG. 13, when a request node transmits a query, the query is transferred to the root node via an intermediate node in some cases (51).

  The root node that has received the query searches the index information managed (stored) for the content ID included in the query, determines that it is the root node, and communicates with the content node. Inquires about busyness (52).

  Then, the content node recognizes its own communication busyness and transmits communication busyness information corresponding to this to the root node (53). When the root node determines that the communication busy level corresponding to the received communication busy level information is within a predetermined range, that is, the content node is free (54), the above-described stream type content node information table is created. If so, this table is deleted, and the IP address of the content node is transmitted to the request node of the query transmission source as the content request destination in the same manner as usual (55).

  The request node that has received the IP address of the content request destination transmits a content request to the content node corresponding to the IP address (56). Upon receiving the content request, the content node starts distributing the content to the request node that has transmitted the content request (57).

  Further, when the root node determines that the communication busyness is within a predetermined range (54), the non-communication busy instruction information indicating that “the IP address indicating the content node should be transmitted to the request node of the query transmission source”. Is transmitted from the root node to the cache node (58).

  Thereafter, when the request node transmits a query and the query is transferred to the cache node via the intermediate node (59), the cache node sends an IP address indicating the content node as a content request destination to the request of the query transmission source. Transmit to node (60).

  The request node that has received the IP address of the content request destination transmits a content request to the content node corresponding to the IP address (61). The content node that has received the content request starts content distribution to the request node that has transmitted the content request (62).

  Next, another operation of the system S when the communication status of the content node is not busy (congested) will be described with reference to FIG. FIG. 14 shows that the cache node inquires of the content node about the communication busyness before the root node, and the communication busyness corresponding to the received communication busyness information is within a predetermined range, that is, the content node has become free. The operation when it is determined is shown.

  As shown in FIG. 14, when the request node transmits a query, the query is transferred to the cache node via an intermediate node in some cases (71).

  Upon receiving the query, the cache node searches the index information managed (stored) for the content ID included in the query, determines that it is the cache node, and communicates with the content node. The busy degree is inquired (72).

  The content node inquired about the busyness of communication identifies its busyness, and transmits the busyness information corresponding thereto to the cache node (73). When the cache node determines that the communication busyness corresponding to the received communication busyness information is within a predetermined range, that is, the content node is free (74), it indicates that the communication busyness is within the predetermined range. Non-communication busy report information is transmitted to the root node (75).

  Then, the cache node transmits an IP address indicating the content node as the content request destination to the request node that is the transmission source of the query (76).

  The request node that has received the IP address of the content request destination transmits a content request to the content node corresponding to the IP address (77). The content node that has received the content request starts content distribution to the request node that has transmitted the content request (78).

  On the other hand, in the root node that has received the non-communication busy report information (75), if the above-described stream type content node information table has been created, this table is deleted and the non-communication busy similar to the above is performed. The time instruction information is transmitted to the cache node (79). At this time, the root node may send the non-communication busy instruction information only to a cache node other than the cache node that is the transmission source of the non-communication busy report information.

[3.1.2. Operation of each node]
Next, processing performed at each node when the request node makes a content request will be described in detail. As described above, all the node devices 1 included in the content distribution system S include request nodes, cache nodes. , A root node, a content node, a node being downloaded, a stream type content node, an intermediate node on the route, or other nodes, etc.

  For example, when the user operates the input unit 21 provided in the node device 1 to instruct an inquiry about the location of desired content data, the node device 1 functions as a request node that transmits the query. In addition, the node device 1 that has received the query from the request node and inquired about the location of the content data includes the content information (node ID and corresponding IP address) in the index information stored in its storage unit 12. When there is, it functions as a cache node or a root node. Whether it is a cache node or a root node is described in [1.4. As described in [Content Data Registration Method], each node apparatus determines whether or not the inquired content ID is closest to its own node ID (whether there is no other transfer destination by looking at the routing table). 1 is recognized. Further, when it holds the content, it functions as a content node. Further, the node device 1 that is a request node functions as a downloading node when content is being downloaded, and when the content being downloaded at that time is to be distributed to another node device 1. The node device 1 functions as a stream type content node.

  Hereinafter, processing performed in the node device 1 when functioning as each node will be described in detail with reference to FIGS.

  First, with reference to FIG. 15, a description will be given of what processing the control unit 11 performs according to a message (or input processing) received by the node device 1 and which node device such as a request node plays a role. . FIG. 15 is a flowchart showing message analysis processing in the node device 1.

  When the control unit 11 of the node device 1 recognizes that the power is turned on (power on: step S1), it initializes the UI display and the like and the port setting on the display unit 16 of the node device 1 (step S2). Whether or not A determination is made as to whether the power is off (step S3). Normally, since the power is not suddenly turned off, the control unit 11 determines that the power is not turned off (step S3 NO), and determines whether or not a content viewing request is input from the input unit 21 (step S4). ). When the control unit 11 determines that there is “content viewing request input” from the input unit 21 (YES in step S4), the node device 1 operates as a request node and performs query transmission processing (step S5). Note that the request node may then be a downloading node or a stream type content node.

  On the other hand, when the control unit 11 determines that there is no “content viewing request input” from the input unit 21 (NO in step S4), the control unit 11 determines whether a message is received from the communication unit 20. (Step S6). When it is determined that the control unit 11 has not received a message from the communication unit 20 (step S6 NO), the process returns to step S3, and when the control unit 11 determines that a message has been received from the communication unit 20 (step S6). S6 YES), the message received from the communication unit 20 is analyzed (step S7).

  When the message analyzed by the control unit 11 is “query”, the node device 1 itself determines whether or not the node device 1 stores the IP address corresponding to the content ID included in the query. Or it is judged whether it is a cache node (step S8). When the IP address corresponding to the content ID included in the query is not stored, the node device 1 is not the root node and the cache node of the content, so the control unit 11 makes such a determination (NO in step S8) and receives it. The process which transfers the done query is performed (step S9). The process of transferring the query is as described above.

  When the IP address corresponding to the content ID included in the query is stored, the control unit 11 of the node device 1 determines whether or not the inquired content ID is closest to its own node ID (see the routing table). Then, it is determined whether the content is a root node or a cache node (step S8). Accordingly, when the control unit 11 determines that the inquired content ID is closest to its own node ID and is itself the root node of the content ID (step S8 root node), the content node (stream type content) A process (1) for transmitting an IP address which is node information (including nodes) is performed (step S10). On the other hand, in step S8, the control unit 11 of the node device 1 determines that the inquired content ID is not the closest to its own node ID and that there is another transfer destination, so that it is the cache node of the content ID. If so (step S8 cache node), processing (2) for transmitting the IP address which is the node information of the content node (including the stream type content node) is performed (step S11).

  If the message analyzed by the control unit 11 is “instruction information”, the node device 1 operates as a cache node or other node device 1 and performs an instruction information handling process (step S12). If the message analyzed by the control unit 11 is “report information”, the node device 1 operates as a root node, a cache node, or other node device 1 and performs a report information handling process (step S13).

  When the message analyzed by the control unit 11 is “content request (shared information request information)”, the node device 1 operates as a content node or a stream type content node, and performs content distribution processing (step S14).

  After each of these steps S5 and S9 to S14, the control unit 11 of the node device 1 returns to the process of step S3. Whether the control unit 11 has been turned off again. When the node device 1 is powered off (step S3), the control unit 11 determines that the power is turned off (step S3 YES), and ends this process (end).

  The processing of each node device 1 will be described below.

[3.1.2.1. Request node processing]
The processing of the request node and the processing of the request node becoming the downloading node and the stream type content node (step S5 described above) will be described using FIG. FIG. 16 is a flowchart showing processing performed when the program stored in the control unit 11 of the request node is executed by the control unit 11.

  When the user operates the input unit 21 to input a content title or the like and an inquiry about the location of the desired content data is made (step S5: start), the control unit 11 that recognizes this, And generating a content ID indicating the content data (unique identification information corresponding to the shared information) and storing a query including the generated content ID in the storage unit 12. The reference is transmitted to another node device 1 (step S21). The selection method of the other node device 1 is based on the method described in detail in the “1-3 Content Data Search Method” described above.

  Next, when the IP address information (node information) of the content node is received from the root node or the cache node (step S22), the content request information is transmitted to the content node specified by the IP address information (step S23). The content is received (step S24). At this time, the node device 1 becomes a downloading node. Next, it is determined whether the content reception is completed (step S25). If the content reception is completed as it is (step S25 YES), the received (downloaded) content is reproduced (step S26), and the replica node (actually) Is registered as (not distinguishable from the content node because it holds the same content as the content node) (step S27), and the process ends (end).

  On the other hand, when the content reception is not completed in step S25 (NO in step S25), the control unit 11 determines whether or not there is a reception status inquiry from the root node (step S28), and there is no reception status inquiry. (NO in step S28), the process returns to step S25 to continue receiving content while repeating the determinations in S25 and S28.

  If there is a reception status inquiry (YES in step S28), the control unit 11 transmits the received reception status information to the root node of the inquiry source (step S29). Next, it is determined whether or not there has been an inquiry about whether or not the content of the currently received content can be distributed to another node device (step S30). If there is no inquiry about whether or not the content can be distributed, the control unit 11 makes such a determination (NO in step S30), and continues reception until the reception of the content is completed (step S31), and proceeds to step S26 described above.

  On the other hand, when there is an inquiry about “contents can be distributed”, the control unit 11 makes such a determination (YES in step S30), and whether or not there is an environment in which contents can be distributed to other node devices 1. Is determined (step S32).

  If the control unit 11 determines that the content can be distributed to another node device 1 (YES in step S32), a message indicating that the content can be distributed to the other node device 1 is transmitted to the root node of the inquiry source. (Step S33), the process proceeds to Step S31 described above. On the other hand, if the control unit 11 determines that the environment is not capable of delivering the content to other node devices (NO in step S32), a message indicating that the content cannot be delivered to the other node device is transmitted to the root node as the inquiry source. (Step S34), the process proceeds to Step S31 described above. Then, when the reception of the content is completed in step S31, the downloaded content is reproduced (step S26) in the same manner as described above, and the replica node (actually the same content as the content node is retained) to the root node. Therefore, it is not distinguished from the content node) (step S27), and this process ends (end).

[3.1.2.2. Process root node]
The root node processing (steps S10 and S13 described above) will be described with reference to FIGS. FIG. 17 and FIG. 18 are flowcharts showing processing performed when the program stored in the control unit 11 of the root node is executed by the control unit 11.

First, the processing when a query that contains the same content ID and the content ID in the combination of the content ID and the IP address for storing root node receives the root node with reference to FIG. 17.

  From the content ID included in the query after the query is transferred, the control unit 11 of the root node determines that the inquired content ID is closest to its own node ID and has no transfer destination. (Step S8 root node), the process (1) for transmitting the IP address of the content node is started (Step S10: Start).

  First, the control unit 11 searches for an IP address corresponding to the content ID included in the query, and inquires about the busyness of communication with the content node (step S41). Next, the control unit 11 determines whether or not the communication busyness is within a predetermined range from the communication busyness information received from the content node (step S42). When the communication state of the content node is extremely congested and the control unit 11 determines that the busyness of communication is outside the predetermined range (step S42 NO), the node device that is delivering content to the content node again (the above-described downloading node) (Step S43).

  When receiving the distributing node information (IP address) indicating the content downloading node from the content node (step S44), the control unit 11 starts creating a stream type content node information table, and the node device corresponding to the IP address An inquiry is made to (downloading node) about the content reception status (step S45).

  Next, the control unit 11 provides information on the reception status of the content (information such as query transmission date / time of each downloading node, download start date / time, download source IP address, number of HOPs with the download source, download status, assumed effective bandwidth). When receiving from each downloading node (step S46), information (environment evaluation value, number of downloadable devices, number of tree branch stages, new download source IP address) for selecting a stream type content node based on this reception status information The number of devices being downloaded) is determined (step S47). At this time, the download source IP address is the IP address of the original content node, and the number of devices being downloaded is 0 (zero).

  The information for selecting these stream type content nodes is as described above with reference to FIG. 9A, and the control unit 11 has the environment evaluation value A, B, or C, and the stream type content. It is determined whether there is a downloading node that is determined to be a node (step S48). At this time, if the control unit 11 determines that there is a node being downloaded that has an environmental evaluation value of A, B, or C and is determined to be a stream-type content node (YES in step S48), such a download is in progress. The node is inquired of “Can the content currently being received be distributed to other node devices?” (Step S49).

  On the other hand, when the control unit 11 determines that there is no node being downloaded that is determined to be a stream type content node with an environmental evaluation value of A, B, or C (NO in step S48), the control unit 11 returns to step S43, A request node that can become a stream type content node again is selected through S44 to S47.

  Next, the control unit 11 of the root node transmits “contents can be distributed to other node devices” from one or more request nodes as inquiry transmission destinations as described above in step S33 or “others” as in step S34. The message “content distribution is not possible to other node devices” is received (step S50), and the node being downloaded as the transmission source of the message “content distribution is possible to other node devices” is recognized as a stream type content node. (Step S51).

  Next, the control unit 11 selects one or a plurality of node devices 1 as the content request destination of the request node that has received the query from the stream type content nodes recognized as the content request destination (step S52). The IP address of the selected node device 1 is transmitted to the request node (step S53). At this time, the control unit 11 selects the stream type content node so that the topology of the tree type communication form grows in a balanced manner (or matches the predetermined policy for selecting the stream type content node). To inform the request node. Next, the control unit 11 transmits to the cache node communication busy instruction information indicating that “the IP address indicating the stream type content node should be transmitted to the request source node of the query” (step S54), and ends the processing. (End)

  On the other hand, when the control unit 11 determines in step S42 that the communication status of the content node is relatively free and the communication busyness is within a predetermined range (YES in step S42), the control unit 11 receives the request that has received the query. As a content request destination of the node, one or a plurality of node devices 1 are selected from normal content nodes (step S55), and the IP address of the selected node device 1 is transmitted to the request node (step S56).

  In addition, when the above-described stream type content node information table has been created, the control unit 11 performs a process for deleting this table (step S57). Specifically, even if the content node is not busy, there is a high possibility that the content is still downloaded in a tree-type communication form. Therefore, when the root node deletes the information table, if there is a request node that downloads content in a tree-type communication mode, the connection should be changed so that the content is downloaded directly from the content node. An example is sending the instruction information to the request node.

  Also, when the root node deletes the information table, the request node that is downloading the content in the tree-type communication mode is allowed to continue downloading, and the information table is held until the download of the request node is completed. This is an example. Even if the information table is held, after recognizing that the communication busyness is within the predetermined range (step S42), the new information is not added to the information table, and the request node of which the download has been completed. The information table is deleted in order from the information. When all the request nodes are deleted from the information table, the information table itself is deleted. If the stream type content node information table is not created, the control unit 11 immediately proceeds to the process of step S58.

  Next, the control unit 11 transmits the non-communication busy instruction information to the effect that “the IP address indicating the content node should be transmitted to the request node that transmitted the query” to the cache node (step S58), and ends the process. (End)

  Although not clearly shown in FIG. 17, the root node receives the transmitted information when the cache node transmits the IP address of the stream type content node to the request node (step S87 described later). ). With this transmitted information, the root node can recognize which request node requests content from which stream type content node. For this reason, the information table can be updated based on the transmitted information in addition to the information on the stream type content node that the request node has informed.

  Next, the operation of the node apparatus 1 when the node apparatus 1 receives report information such as busy communication report information or non-communication busy report information (step S13 in FIG. 15) will be described with reference to FIG.

  When receiving the report information from the other node device 1, the control unit 11 starts the report information handling process (step S13: start). First, the control unit 11 determines whether or not communication busy report information has been received (step S61). When it is determined that the control unit 11 has received the busy communication report information (YES in step S61), the content node is inquired of the node device that is delivering the content (the above-described downloading node) (step S62). This step S62 is the same as step S43 in FIG. Subsequent steps S63 to S70 are the same as steps S44 to S51 in FIG. In this way, a node device that becomes a stream type content node is authorized as the content request destination of the request node, and the communication is busy that “the IP address indicating the stream type content node should be transmitted to the request node of the query transmission source” The instruction information is transmitted to the cache node (step S71), and the process ends (end).

  On the other hand, if it is determined in step S61 that the control unit 11 has not received the busy communication report information (NO in step S61), it is then determined whether the non-communication busy report information has been received (step S72). When the control unit 11 determines that the non-communication busy report information has been received (YES in step S72), if the above-described stream type content node information table has been created, this table is deleted as in step S57 described above. (Step S73), and transmits non-communication busy time indication information to the effect that “the IP address indicating the content node should be transmitted to the request source node of the query” (step S74), End processing (END).

  If the control unit 11 determines in step S72 that the non-communication busy report information has not been received (NO in step S72), since other report information has been received, processing corresponding to the report information is performed ( Step S75), the process ends (END).

  Although not shown, when the root node receives a query after transmitting communication busy instruction information or non-communication busy instruction information, the root node may operate as described with reference to FIG. The IP address may be returned to the request node as the query transmission source in accordance with the instruction information transmitted by itself for a predetermined period.

[3.1.2.3. Cache node processing]
The cache node processing (steps S11 and S12 described above) will be described with reference to FIGS. FIG. 19 and FIG. 20 are flowcharts showing processing performed when the program stored in the control unit 11 of the cache node is executed by the control unit 11.

First, the cache node for explaining a process performed when the cache node a query that contains the same content ID and the content ID in the combination of the content ID and the IP address for storing received with reference to FIG.

  The control unit 11 of the cache node determines that the content ID inquired from the content ID included in the query is not closest to the node ID of the cache node and there is another transfer destination. (Step S8 cache node), and starts processing for transmitting the IP address of the content node (step S11: start).

  The control unit 11 searches for an IP address corresponding to the content ID included in the query, and inquires about the busyness of communication with the content node (step S81). Next, the control unit 11 determines whether or not the communication busyness is within a predetermined range from the communication busyness information received from the content node (step S82). If the communication state of the content node is extremely congested and the control unit 11 determines that the communication busyness is outside the predetermined range (NO in step S82), the control unit 11 communicates to the root node that the communication busyness is outside the predetermined range. Busy report information is transmitted (step S83).

  Next, the control unit 11 of the cache node receives busy instruction information indicating that “the IP address indicating the stream type content node should be transmitted to the request source node of the query” (step S84), and the instruction information The IP address corresponding to the included stream type content node is selected as the content request destination of the request node receiving the query (step S85), and the IP address of the selected node device 1 is transmitted to the request node (step S85). S86). Next, the control unit 11 transmits transmitted information indicating that “the IP address of the stream type content node has been transmitted to the request node” to the root node (step S87), and ends the process (end). The transmitted information is information including which request node is notified of which stream type content node's IP address.

  On the other hand, in step S82, when the control unit 11 determines that the communication status of the content node is relatively free and the communication busyness is within a predetermined range (YES in step S82), “the communication busyness is within the predetermined range”. The non-communication busy report information is transmitted to the root node (step S88), and one or a plurality of node devices 1 are selected from the normal content nodes as the content request destination of the request node receiving the query. (Step S89), the IP address of the selected node device 1 is transmitted to the request node (Step S90), and the process is terminated (End).

  Next, the operation of the node apparatus 1 when the node apparatus 1 receives instruction information such as busy instruction information or non-communication busy instruction information (step S12 in FIG. 15) will be described with reference to FIG.

  When receiving the instruction information from the other node device 1, the control unit 11 starts the instruction information handling process (step S12: start). First, the control unit 11 determines whether or not the busy communication instruction information has been received (step S91). If it is determined that the control unit 11 has received the busy instruction information (step S91 YES), the IP address of the stream type content node included in the instruction information is stored as information to be returned when the query is received (step S91). S92), the process ends (END).

  On the other hand, if it is determined in step S91 that the control unit 11 has not received the busy communication instruction information (NO in step S91), it is then determined whether or not the non-communication busy instruction information has been received (step S93). When the control unit 11 determines that the non-communication busy instruction information has been received (YES in step S93), it stores that the IP address of the normal content node is returned when the query is received (step S94), and ends the process. (End)

  In step S93, if the control unit 11 determines that the non-communication busy instruction information has not been received (NO in step S93), since other instruction information has been received, processing corresponding to the instruction information is performed ( Step S95), the process is terminated (END).

  Although not shown, when the cache node receives a query after receiving busy instruction information or non-communication busy instruction information, the cache node may operate as described with reference to FIG. The IP address may be returned to the request node that is the source of the query according to the received instruction information for a predetermined period.

[3.1.2.4. Processing content nodes and stream type content nodes]
The content distribution process (the above-described step S14) of the content node and the stream type content node will be described with reference to FIG. FIG. 21 is a flowchart illustrating processing performed when the program stored in the control unit 11 of the request node is executed by the control unit 11.

  When the control unit 11 of the content node or stream type content node recognizes that the content request has been received from the request node, it starts the content distribution process (step S14: start).

  Upon receiving the content request from the request node, the control unit 11 starts content distribution to the request node that is the transmission source of the content request (step S101), and the IP address of the request node that is currently distributing the content of the downloading node It is stored as node information during distribution (step S102). The stored delivering node information is transmitted from the root node to the content node when an inquiry is made about the node being downloaded.

  The control unit 11 continues the content distribution (step S103), determines whether the content distribution is completed (step S104), and continues the content distribution until the content distribution is completed (step S104 NO) (step S104). S103) When it is determined that the content distribution has been completed (YES in step S104), the process ends (END).

  The content distribution operation of the content node and the stream type content node is the same as described in the flowchart above, but the stream type content node is receiving content from other content nodes at the start of content distribution. Different.

  Although not shown, when the content node is inquired about the busyness of communication from the root node or the cache node, the content node recognizes the busyness of the content node itself and transmits the busyness information to the inquiring node device.

[4. Variant]
In the present embodiment, the root node and the cache node directly communicate the communication status to the content node in order to determine the communication busyness indicating the degree of local concentration of communication with other node devices (request nodes) in the content node. Although inquiring, it is not limited to this embodiment. The number of IP addresses of one content node transmitted by a root node or a cache node per certain time (the number of IP address transmissions of content), as will be described below when the communication busyness is outside the predetermined range and within the predetermined range. ), Or the number of times the root node or cache node has received a query from the request node per certain time (the number of received queries), etc., can be used to determine the communication busyness.

  In addition, the root node and the cache node may be configured to inquire the communication status to the content node for the first time when the number of IP address transmissions and the number of query receptions of the above content exceeds a predetermined value. In this case, since the number of communications is reduced, the load on the content distribution system S is reduced.

  Here, regarding “communication busy is out of a predetermined range”, when local concentration of communication of content nodes occurs, specifically, as described in the embodiment, the content node itself is “communication busy”. If the root node or the cache node informs (transmits) the IP address of one or more content nodes over a predetermined time per fixed time, the root node or the cache node receives a predetermined time from the request node. When a predetermined number or more of queries are received, the number of request nodes that make a distribution request to one content node again increases, and the like can be defined as appropriate.

  In addition, for “communication busyness within a predetermined range”, if the communication of content nodes is not originally crowded, the number of replica nodes storing content copies of content nodes has increased to a certain number or more, and content distribution has become stable. In the case where the local concentration of communication of the content node is canceled such as when the request node has decreased to a predetermined number or less per certain time, specifically, as described in the embodiment, the content node itself is “ When it is determined that the communication is not busy, or when the root node or cache node informs (transmits) the IP address of one content node less than a predetermined number per fixed time, the root node or cache node requests When less than a certain number of queries are received from a node per certain time, one content node If the request node for distributing requests to de again is exhausted, can be defined as equal, it can be appropriately determined in accordance with embodiments. The predetermined range in the above-mentioned “communication busyness is within a predetermined range” and “communication busyness is outside the predetermined range” may not be the same.

  In the content distribution system S of the present embodiment, after the stream type content node finishes receiving the content from the content node after the so-called tree type communication form using the stream type content node, the stream type content node Communication with the node is cut off, and it can function as a content node (replica node). As for the node device that becomes the content node in this way, the root node or the cache node can transmit the IP address of the new content node to the request node by a conventionally known method. In addition, when such content nodes increase, the root node considers this, and a node device (original content node, new content node, or stream type content node) that informs the request node of the IP address. You can choose.

  The “information storage node device” in the present invention has been described as a content node in the present embodiment, but may include not only the content node but also a replica node storing a copy of the content. In the embodiment, the term “replica node” is used for convenience. However, since the content node and the replica node actually have the same content data, they are not distinguished from each other. When the replica node is included in the “information storage node device”, for example, the root node and the cache node can inquire about the busyness of communication with the content node and all replica nodes. In addition, the root node and cache node inquire the communication busyness to all the corresponding node devices until the number of content nodes and replica nodes is less than a certain number, and if the number of content nodes and replica nodes exceeds a certain number, priority is given. It may be configured such that only a certain number of node devices are inquired about the busyness of communication from the higher rank. This priority can be arbitrarily determined by the root node and the cache node based on the response speed of the communication busyness information.

  As described above, the “information partial storage node device” in the present invention is a request node that first requests distribution of content, is a downloading node while receiving content, and is a stream type content when it is recognized as a root node. It becomes a node and distributes content to other request nodes.

  In this embodiment, as described in the so-called tree-type communication form, as described in the lower frame of FIG. 8 and FIG. 10B, the content node 1h, the stream-type content nodes 1e and 1z (node numbers <1>, <2 >; First stage), new request nodes 1j, 1f, 1d, 1a (node numbers <4>, <5>, <6>; second stage) are formed in this order. The tree-type communication mode is managed by the root node using the topology information shown in FIGS. 9A and 10A, so that the request nodes 1j, 1f, 1d, and 1a in the second stage are also stream-type content nodes. Further, a new request node (node number <7>; third stage) may be communicated downstream thereof.

  In this embodiment, in order for the root node to know the location of the cache node, as described with reference to FIG. 6 in “1.4. Content Data Registration Method”, the cache node has its own IP address (node information). Is added to the public message and transferred. In order for the root node to transmit information to the cache node, the method is not limited to the above method. For example, when registering content data, a public message is transferred from the content node to the root node via the cache node. Each cache node stores the IP address of the message transmission source, so that information can be transferred from the root node to the cache node in the reverse direction.

  In this embodiment, the root node has communication busy instruction information transmitting means, non-communication busy instruction information transmitting means, communication busy report information receiving means, and non-communication busy report information receiving means, and the cache node communicates. Busy report information transmitting means, non-communication busy report information transmitting means, busy communication instruction information receiving means, and non-communication busy instruction information receiving means. Actually, since the cache node may transfer the busy communication instruction information / non-communication busy instruction information as described above, the cache node is busy communication non-communication report information receiving means and non-communication busy report information receiving means. May have.

  Further, a program corresponding to each operation of the node device 1 described above is recorded in an information recording medium such as a flexible disk or a hard disk, or acquired and recorded via a network such as the Internet, and this is stored in a microcomputer. The microcomputer can be caused to function as the control unit 11 according to the embodiment by reading out and executing the program.

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 explanatory drawing of ID space. It is a figure which shows an example of a mode that a routing table is produced by DHT. (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 which shows an example of a mode that the node apparatus 1 which is a storage source of content data is searched by DHT. It is the figure which represented a mode that the public message of a content node was transferred in the spanning tree shape. 2 is a diagram illustrating a schematic configuration example of a node device 1. FIG. 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 (1) explaining operation | movement at the time of a root node selecting a stream type | mold content node. It is FIG. (2) explaining operation | movement at the time of a root node selecting a stream type | mold content node. FIG. 10 is a sequence chart (1) showing exchange of various information such as a query between a request node, a root node, a content node, a downloading node, a stream type content node, and a cache node when communication busyness is outside a predetermined range. . It is a sequence chart (2) showing transmission / reception of various information such as a query between a request node, a root node, a content node, a downloading node, a stream type content node, and a cache node when communication busyness is outside a predetermined range. . It is a sequence chart (3) showing exchange of various information such as a query between a request node, a root node, a content node, a downloading node, a stream type content node, and a cache node when the communication busyness is within a predetermined range. . It is a sequence chart (4) showing exchange of various information such as a query between a request node, a root node, a content node, a downloading node, a stream type content node, and a cache node when the communication busyness is within a predetermined range. . It is a flowchart which shows the process which analyzes the message received in the control part of a node apparatus. It is a flowchart which shows the process in the control part of a request node. It is a flowchart which shows the node information transmission process (1) in the control part of a root node. It is a flowchart which shows the report information corresponding | compatible process in the control part of a root node. It is a flowchart which shows the node information transmission process (2) in the control part of a cache node. It is a flowchart which shows the instruction information corresponding | compatible process in the control part of a cache node. It is a flowchart which shows the process in the control part of a content node and a stream type content node.

Explanation of symbols

1 node device 8 network 9 overlay network 11 control unit 12 storage unit 13 buffer memory 14 decoder unit 15 video processing unit 16 display unit 17 audio processing unit 18 speaker 20 communication unit 21 input unit 22 bus S content distribution system

Claims (20)

Comprising a plurality of node devices connected through the network, the contents to be distributed and stored in the plurality of node devices, it is distributed from the node device included in the plurality of node devices to another node device An information distribution system,
One node device included in the plurality of node devices is:
Request information for requesting transmission of node information indicating the node device capable of transmitting the content , the request information including unique identification information corresponding to the content included in the plurality of node devices Request information receiving means for receiving from the node device;
The node information indicating a content storage node device that is the node device that stores the specific content among the content that is distributed and stored in the plurality of node devices; unique identification information corresponding to the content; Storage means for associating and storing
The identification information included in the request information, if stored in the storage unit, the content storage node the node information corresponding to the identification information included in the request information indicating device and another node device Communication busyness recognition means for authenticating communication busyness indicating the degree of local concentration of communication with
The node information indicating the content receiving node device that is the node device that is receiving the content from the content storage node device indicated by the node information corresponding to the identification information is included in the content storage node device or the request information. Obtaining means for obtaining from the other node device that similarly stores the node information corresponding to the identification information included;
When the communication busyness is out of a predetermined range, the node information acquired by the acquisition unit as the node information indicating the streaming distribution node device that is the node device that performs streaming distribution of the content, Streaming distribution node information transmitting means for transmitting to the node device of the request information transmission source;
When the communication busyness is within a predetermined range, the node information stored in the storage unit corresponding to the identification information included in the request information is used as the node device that is the transmission source of the request information. Content storage node information transmitting means for transmitting to:
An information distribution system comprising: Comprising a plurality of node devices connected through the network, the contents to be distributed and stored in the plurality of node devices, it is distributed from the node device included in the plurality of node devices to another node device An information distribution method in an information distribution system,
Wherein the plurality of node devices one node device included in, a request information for requesting transmission of node information indicating the node device can transmit the content and unique identification information corresponding to the content A request information receiving step for receiving the request information including from the node devices included in the plurality of node devices;
The content storage node device, wherein the one node device is the node device that stores the specific content among the content stored in the plurality of node devices in which the identification information included in the request information is distributed and stored The node information corresponding to the identification information included in the request information is stored in a storage unit that stores the node information indicating the unique identification information corresponding to the content in association with each other. A communication busyness qualifying step for certifying a busyness of communication indicating a degree of local concentration of communication between the content storage node device and another node device indicated by:
The node information indicating the content receiving node device, which is the node device that is receiving the content from the content storage node device indicated by the node information corresponding to the identification information, is stored in the content storage. An acquisition step of acquiring from the node device or another node device that similarly stores the node information corresponding to the identification information included in the request information;
When the communication busyness is outside a predetermined range, the one node device is acquired in the acquisition step as the node information indicating the streaming distribution node device that is the node device that performs streaming distribution of the content. The streaming delivery node information transmitting step for transmitting the node information to the node device that is the transmission source of the request information;
When the one node device has the busy communication level within a predetermined range, the node information stored in the storage unit corresponding to the identification information included in the request information is changed to the request information. A content storage node information transmission step for transmitting to the node device of the transmission source;
Information distribution method characterized in that it comprises a. Comprising a plurality of node devices connected through the network, the contents to be distributed and stored in the plurality of node devices, it is distributed from the node device included in the plurality of node devices to another node device A node device in an information distribution system,
Request information for requesting transmission of node information indicating the node device capable of transmitting the content , the request information including unique identification information corresponding to the content included in the plurality of node devices Request information receiving means for receiving from the node device;
The node information indicating a content storage node device that is the node device that stores the specific content among the content that is distributed and stored in the plurality of node devices; unique identification information corresponding to the content; Storage means for associating and storing
The identification information included in the request information, if stored in the storage unit, the content storage node the node information corresponding to the identification information included in the request information indicating device and another node device Communication busyness recognition means for authenticating communication busyness indicating the degree of local concentration of communication with
The node information indicating the content receiving node device that is the node device that is receiving the content from the content storage node device indicated by the node information corresponding to the identification information is included in the content storage node device or the request information. Obtaining means for obtaining from the other node device that similarly stores the node information corresponding to the identification information included;
When the communication busyness is out of a predetermined range, the node information acquired by the acquisition unit as the node information indicating the streaming distribution node device that is the node device that performs streaming distribution of the content, Streaming distribution node information transmitting means for transmitting to the node device of the request information transmission source;
When the communication busyness is within a predetermined range, the node information stored in the storage unit corresponding to the identification information included in the request information is used as the node device that is the transmission source of the request information. Content storage node information transmitting means for transmitting to:
A node device comprising: The node device according to claim 3, wherein
The node busy device is characterized in that the communication busyness recognition means recognizes the busyness of communication by receiving communication busyness information corresponding to the busyness of communication from the content storage node device corresponding to the node information. . The node device according to claim 3 or 4, wherein
The streaming delivery node information transmission means includes
Reception status information receiving means for receiving, from the content receiving node device, reception status information indicating the reception status of the content in the content receiving node device corresponding to the node information acquired by the acquiring means ;
Selection means for selecting, based on the reception status information, at least one or more of the node information indicating the streaming distribution node device from the node information indicating the content receiving node device acquired by the acquisition means;
Have
A node device that transmits the node information indicating the streaming distribution node device selected by the selection unit to the node device that is a transmission source of the request information. The node device according to any one of claims 3 to 5,
Wherein when the communication busy degree is out of the predetermined range, the streaming node the node streaming node information transmission instruction information to be transmitted to the apparatus of the transmission source of the node information indicating a device the request information A node device comprising: streaming delivery node information transmission instruction information transmitting means for transmitting the node information corresponding to the identification information included in the request information to another node device that similarly stores the node information . The node device according to claim 6, wherein
Said when the communication busy degree is within the predetermined range, the content storage node the node content storage node information transmission instruction information to be transmitted to the device of the transmission source of the request information the node information indicative of the device A node device comprising: content storage node information transmission instruction information transmission means for transmitting the node information corresponding to the identification information included in the request information to another node device that similarly stores the node information . The node device according to claim 7, wherein
In- predetermined range report information receiving means for receiving from the node device that is the transmission destination of the streaming delivery node information transmission instruction information , the in- predetermined range report information indicating that the communication busyness is within a predetermined range ,
When the report information within the predetermined range is received,
The content storage node information transmission means transmits the node information stored in the storage means corresponding to the identification information included in the request information to the node device that is the transmission source of the request information,
The content storage node information transmission instruction information transmission means transmits the content storage node information transmission instruction information to another node device that similarly stores the node information corresponding to the identification information included in the request information. A node device characterized by: The node device according to claim 7 or 8, wherein
Out-of- predetermined range report information receiving means for receiving out-of-preset range report information indicating that the busyness of communication is out of a predetermined range from the node device that is the transmission destination of the content storage node information transmission instruction information ,
When receiving the report out of the predetermined range ,
The streaming distribution node information transmission means transmits the node information indicating the streaming distribution node device to the node device that is the transmission source of the request information,
The streaming distribution node information transmission instruction information transmission means transmits the streaming distribution node information transmission instruction information to another node device that similarly stores the node information corresponding to the identification information included in the request information. A node device characterized by: The node device according to claim 3 or 4, wherein
Said node said streaming node said node streaming node information transmission instruction information to be transmitted to the device of the transmission source of the request information the node information indicative of the device, corresponding to the identification information included in the request information Streaming distribution node information transmission instruction information receiving means for receiving information from other node devices that similarly store information ,
When the streaming distribution node information transmission instruction information is received, the streaming distribution node information transmission means transmits the node information indicating the streaming distribution node device to the node device that is the transmission source of the request information,
The transmission completion information transmitting means for transmitting the transmission completion information indicating that transmits the node information indicative of the streaming node device to another of the node device to the source of the node device of said streaming node information transmission instruction information A node device comprising: The node device according to claim 10, wherein
The nodes of the content storage node the node information the node content storage node information transmission instruction information to be transmitted to the device of the transmission source of the request information that indicates the device, corresponding to the identification information included in the request information Content storage node information transmission instruction information receiving means for receiving information from other node devices that similarly store information ;
When the content storage node information transmission instruction information is received or when the streaming delivery node information transmission instruction information is not received, the content storage node information transmission means corresponds to the identification information included in the request information. And transmitting the node information stored in the storage means to the node device that is the transmission source of the request information . The node device according to claim 10 or 11, comprising:
When the communication busyness is within a predetermined range, report information within a predetermined range indicating that the communication busyness is within a predetermined range, and the node device that is the transmission source of the streaming delivery node information transmission instruction information A node device, further comprising reporting means for transmitting report information within a predetermined range . The node device according to claim 11, wherein
When the communication busyness is out of the predetermined range, out- of- predetermined range report information indicating that the communication busyness is out of the predetermined range is sent to the node device that is the transmission source of the content storage node information transmission instruction information The node apparatus further comprising report information transmission means for transmitting out of a predetermined range to be transmitted to The node device according to any one of claims 3 to 13,
The streaming distribution node information transmitting means transmits the node information indicating the streaming distribution node device to the node device that is a predetermined number or less of the request information for one streaming distribution node device. A node device characterized by the above. Comprising a plurality of node devices connected through the network, the contents to be distributed and stored in the plurality of node devices, it is distributed from the node device included in the plurality of node devices to another node device In the computer included in the node device in the information distribution system,
Request information for requesting transmission of node information indicating the node device capable of transmitting the content , the request information including unique identification information corresponding to the content included in the plurality of node devices A request information receiving step received from the node device;
The node information indicating the content storage node device, which is the node device that stores the specific content among the content stored in the plurality of node devices in a distributed manner, the identification information included in the request information ; The content storage node device indicated by the node information corresponding to the identification information included in the request information when stored in a storage unit that stores unique identification information corresponding to the content in association with each other A communication busyness qualifying step for certifying the busyness of communication indicating the degree of local concentration of communication with the other node devices;
The node information indicating the content receiving node device that is the node device that is receiving the content from the content storage node device indicated by the node information corresponding to the identification information is included in the content storage node device or the request information. An acquisition step of acquiring from the other node device that similarly stores the node information corresponding to the included identification information;
When the communication busyness is out of a predetermined range, the node information acquired in the acquisition step is the node information indicating the streaming distribution node device that is the node device that performs streaming distribution of the content. Streaming distribution node information transmission step for transmitting to the node device of the request information transmission source,
When the communication busyness is within a predetermined range, the node information stored in the storage unit corresponding to the identification information included in the request information is used as the node device that is the transmission source of the request information. Content storage node information transmission step for transmitting to
An information processing program for executing The information distribution system according to claim 1,
Streaming distribution node device authorization means for authorizing the node device that is the transmission source of the request information that is the transmission destination of the node information transmitted from the streaming distribution node information transmission means, as the new streaming distribution node device;
Second storage means for storing the node information transmitted from the streaming delivery node information sending means and the node information indicating the node device authorized as the streaming delivery node device by the authorization means in association with each other; ,
Further comprising
The streaming delivery node information transmission means includes
Selection means for selecting the node information to be transmitted so that the contents are sequentially transferred by the streaming distribution node devices based on the node information stored in association with the second storage means; ,
The streaming distribution node information transmission unit transmits the node information selected by the selection unit to the node device that is a transmission source of the request information. The information distribution system according to claim 16, wherein
The information distribution system, wherein the selection means selects the node information to be transmitted so that a plurality of the streaming distribution node devices form the content distribution route in a tree shape. The information distribution system according to any one of claims 1, 16 and 17,
  The node device that is the transmission source of the request information is:
  When the node information indicating the streaming distribution node device or the content storage node device is received, the content request information for requesting transmission of the content is transmitted to the node device corresponding to the received node information Request information transmission means,
  Have
  The streaming distribution node device or the content storage node device that has received the content request information,
  Content transmitting means for transmitting the content to the node device that is the transmission source of the content request information;
  An information distribution system comprising: The node device according to any one of claims 3 to 14,
Streaming distribution node device authorization means for authorizing the node device that is the transmission source of the request information that is the transmission destination of the node information transmitted from the streaming distribution node information transmission means, as the new streaming distribution node device;
Second storage means for storing the node information transmitted from the streaming delivery node information sending means and the node information indicating the node device authorized as the streaming delivery node device by the authorization means in association with each other; ,
Further comprising
The streaming delivery node information transmission means includes
Selection means for selecting the node information to be transmitted so that the contents are sequentially transferred by each of the streaming distribution node devices based on the node information stored in association with the second storage means; ,
The streaming distribution node information transmission unit transmits the node information selected by the selection unit to the node device that is a transmission source of the request information. The node device according to claim 19, wherein
The node device, wherein the selection unit selects the node information to be transmitted so that a plurality of the streaming distribution node devices form the content distribution route in a tree shape.

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