Abstract: To prevent a preview of contents by a person who does not have a right to view or listen, by distributing encoded contents data which are difficult for a third person to decode. A new participation terminal apparatus, as well as transmitting a participation request to a parent terminal apparatus of a connection destination candidate, transmits a participation disclosure key for encoding a contents decoding key. The parent terminal of the connection destination candidate which receives the participation disclosure key from the new participation terminal apparatus generates an encoded decoding key, which is a contents decoding key encoded using the participation disclosure key received, and transmits it to the new participation terminal apparatus. The new participation terminal apparatus decodes the encoded decoding key received, using a participation secret key stored in a participation key storage section, acquiring a contents decoding key.

Abstract: A node device in a tree-type broadcast system having hierarchy levels of node devices while locating a broadcast device at its top, whereby information is sequentially transferred from a higher hierarchy level to a lower hierarchy level, the node device including: a means for receiving connection destination candidate information, broadcasted from the node device in the higher hierarchy currently connected or from the broadcast device; a means for specifying a node device suitable as a reconnection destination candidate out of the connection destination candidate information; a means for memorizing network address information, being the reconnection destination candidate; and a means for selecting one node device memorized in the reconnection destination candidate memory means as the reconnection destination and connecting to it when the connection to the node device or the broadcast device is released and the own node device is newly reconnected to another node device.

Abstract: A tree type network system including an information delivery device, a plurality of node devices, and an administration, wherein the node devices are connected in a tree-like shape via a communication route while placing the information delivery device in an uppermost level and forming a plurality of hierarchy levels, and the delivery information is sequentially transferred from the node device in an upper hierarchy level to the node devices in lower hierarchy levels, wherein the administration device includes: a device for acquiring attribute information of a node device, which transmits participation request information, and determines device information on the basis of the attribute information thus acquired upon receipt of participation request information of requesting device information of node device as connection candidate, and a device for transmitting the connection end candidate information thus determined to the node device which transmits the participation request information.

Abstract: A broadcast device in a tree-type broadcast system forming plural hierarchy levels with the broadcast device located at the top and connecting the nodes so as to be sequentially transferred from higher to lower nodes, wherein the nodes select a first mode determining a reconnection destination by acquiring node information from a server or a second mode determining a reconnection destination by acquiring node information of the reconnection destination candidate, and determines the reconnection destination by acquiring the node information according to the mode currently selected when the higher nodes are disconnected and the node except for the own is reconnected, and the broadcast device monitors a load status of the server, and broadcasts to switch selection to the second mode to thereby enable sequential transfer of the switch instruction from the higher to the lower nodes when a monitor level becomes a threshold level or more.

Abstract: A content distribution system in which content is distributed from a broadcasting station via a plurality of nodes connected in a hierarchical tree structure, including: a base tree obtained by connecting the plurality of nodes in a hierarchical tree structure using the broadcasting station as an apex; an extension tree obtained by connecting the plurality of other nodes in a hierarchical tree structure using, as an apex, a first root node as any of the nodes included in the base tree; and a topology controller for controlling a topology of each of the nodes belonging to the base tree. The first root node controls the topology of each of the nodes belonging to the extension tree using the first root node as an apex.

Abstract: A lost packet in a plurality of packets broadcasted from a broadcasting apparatus is detected. Packet complement request information indicative of a packet complement request for complementing the lost packet is transmitted to a device in a high hierarchical level, and a dummy packet for holding transmission of the packet complement request information for a predetermined hold time is transmitted in place of the lost packet to a node device connected in a low hierarchical level.

Abstract: A node device having a plural hierarchy levels in a tree-like shape while placing a broadcast device at a top of the levels and connecting the node devices through a communication means, wherein content data is sequentially transferred from the node device at an upper hierarchy level to that at a lower hierarchy level, including: a control means for displaying a predetermined screen for a user; and a means for carrying out a process of participating in the system when a broadcast information screen related to broadcast of the content data is displayed and for carrying out a process of withdrawing from the system when display is finished, wherein when transiting to display in another screen, the participation and withdrawal control means carries out the withdrawal process on a condition that the broadcast information screen is not displayed again within a waiting time previously set up.

Abstract: To provide a contents distribution system, method and the like, wherein even a node apparatus with a small storage capacity, such as in the case of a set-top box, can function as a root node apparatus in a P2P type of contents distribution system having a plurality of node apparatus disposed dispersed in a network by a DHT (Distributed Hash Table), or the like. A node apparatus includes a distribution source information storage section having a management information storage area storing first position information, which is position information of a management subject contents holding node apparatus holding contents data which are a subject of management, and an extension management information storage area storing second position information, which is position information of a node apparatus holding position information of the management subject contents holding node apparatus.

Abstract: A separability control device formed by connecting plural node devices in a tree-like shape while forming plural hierarchy levels placing a delivery device at a top to enable content data from the delivery device to be sequentially transferred from the node device on an upper hierarchy level to the node device on an lower hierarchy level, including: a simultaneous separation process upper limit number determination means for determining a simultaneous separation process upper limit number being an upper limit number of the node devices capable of separating simultaneously based on the number of the participating node devices; a separation request information receiving means; and a separation permission notification means for sending a separation permission notification of permitting the node device being a separation request information sending source when the number of the node devices currently under the separation process does not reach the simultaneous separation process upper limit number.

Abstract: In order that a loop does not occur when switching upstream terminal apparatus, to provide an information distribution system capable of preemptively detecting a distribution route loop, and avoiding the loop, a terminal apparatus and a program used in the same system, as well as a loop connection avoidance method. A terminal apparatus B which has received loop connection detection information from upstream determines whether or not a downstream terminal apparatus of a control path which is not a distribution route along which contents information is flowing, and a source of the loop connection detection information match and, in the event that they match, determines that a loop will occur. By this means, it is possible to determine in advance that a loop will occur, before switching an upstream connection destination.

Abstract: A terminal apparatus in a contents distribution system stores previously connected terminal apparatus, correlated to a contents channel. Also, the terminal apparatus, in the event that an instruction to change a contents channel is issued, selects a terminal apparatus, from among the previously connected terminal apparatus, corresponding to the contents channel for which the change instruction has been issued, and requests of the selected terminal apparatus a connection destination candidate corresponding to the contents channel for which the change instruction has been issued. Then, the terminal apparatus selects the requested connection destination candidate corresponding to the contents channel, and notifies the terminal apparatus which has requested the connection destination candidate. Then, the terminal apparatus receives, and connects to, the reported connection destination candidate.

Abstract: A distribution system is provided, which is capable of distributing content more stably as compared with the case where connection is newly changed after distribution of content is stopped. In a distribution system in which a plurality of nodes are connected in a hierarchical tree shape and content is distributed to any of the nodes, a content distribution state is detected, and a quality parameter (which is controlled by a connection destination introducing server) indicative of a criterion to determine whether the state deteriorates or not is stored in a node. When distribution is continued, and the state of the distribution becomes worse than the criterion, an upstream node introduction request message is transmitted to a connection destination introducing server and, according to a reply to the message, connection is changed.

Abstract: A lost packet in a plurality of packets broadcasted from a broadcasting apparatus is detected. Packet complement request information indicative of a packet complement request for complementing the lost packet is transmitted to a device in a high hierarchical level, and a dummy packet for holding transmission of the packet complement request information for a predetermined hold time is transmitted in place of the lost packet to a node device connected in a low hierarchical level.

Abstract: A broadcast device in a tree-type broadcast system forming plural hierarchy levels with the broadcast device located at the top and connecting the nodes so as to be sequentially transferred from higher to lower nodes, wherein the nodes select a first mode determining a reconnection destination by acquiring node information from a server or a second mode determining a reconnection destination by acquiring node information of the reconnection destination candidate, and determines the reconnection destination by acquiring the node information according to the mode currently selected when the higher nodes are disconnected and the node except for the own is reconnected, and the broadcast device monitors a load status of the server, and broadcasts to switch selection to the second mode to thereby enable sequential transfer of the switch instruction from the higher to the lower nodes when a monitor level becomes a threshold level or more.

Abstract: A separability control device formed by connecting plural node devices in a tree-like shape while forming plural hierarchy levels placing a delivery device at a top to enable content data from the delivery device to be sequentially transferred from the node device on an upper hierarchy level to the node device on an lower hierarchy level, including: a simultaneous separation process upper limit number determination means for determining a simultaneous separation process upper limit number being an upper limit number of the node devices capable of separating simultaneously based on the number of the participating node devices; a separation request information receiving means; and a separation permission notification means for sending a separation permission notification of permitting the node device being a separation request information sending source when the number of the node devices currently under the separation process does not reach the simultaneous separation process upper limit number.

Abstract: A node device in a tree-type broadcast system having hierarchy levels of node devices while locating a broadcast device at its top, whereby information is sequentially transferred from a higher hierarchy level to a lower hierarchy level, the node device including: a means for receiving connection destination candidate information, broadcasted from the node device in the higher hierarchy currently connected or from the broadcast device; a means for specifying a node device suitable as a reconnection destination candidate out of the connection destination candidate information; a means for memorizing network address information, being the reconnection destination candidate; and a means for selecting one node device memorized in the reconnection destination candidate memory means as the reconnection destination and connecting to it when the connection to the node device or the broadcast device is released and the own node device is newly reconnected to another node device.

Abstract: To prevent a preview of contents by a person who does not have a right to view or listen, by distributing encoded contents data which are difficult for a third person to decode. A new participation terminal apparatus, as well as transmitting a participation request to a parent terminal apparatus of a connection destination candidate, transmits a participation disclosure key for encoding a contents decoding key. The parent terminal of the connection destination candidate which receives the participation disclosure key from the new participation terminal apparatus generates an encoded decoding key, which is a contents decoding key encoded using the participation disclosure key received, and transmits it to the new participation terminal apparatus. The new participation terminal apparatus decodes the encoded decoding key received, using a participation secret key stored in a participation key storage section, acquiring a contents decoding key.

Abstract: A node device having a plural hierarchy levels in a tree-like shape while placing a broadcast device at a top of the levels and connecting the node devices through a communication means, wherein content data is sequentially transferred from the node device at an upper hierarchy level to that at a lower hierarchy level, including: a control means for displaying a predetermined screen for a user; and a means for carrying out a process of participating in the system when a broadcast information screen related to broadcast of the content data is displayed and for carrying out a process of withdrawing from the system when display is finished, wherein when transiting to display in another screen, the participation and withdrawal control means carries out the withdrawal process on a condition that the broadcast information screen is not displayed again within a waiting time previously set up.

Abstract: To provide a contents distribution system, method and the like, wherein even a node apparatus with a small storage capacity, such as in the case of a set-top box, can function as a root node apparatus in a P2P type of contents distribution system having a plurality of node apparatus disposed dispersed in a network by a DHT (Distributed Hash Table), or the like. A node apparatus includes a distribution source information storage section having a management information storage area storing first position information, which is position information of a management subject contents holding node apparatus holding contents data which are a subject of management, and an extension management information storage area storing second position information, which is position information of a node apparatus holding position information of the management subject contents holding node apparatus.

Abstract: A content distribution system in which content is distributed from a broadcasting station via a plurality of nodes connected in a hierarchical tree structure, including: a base tree obtained by connecting the plurality of nodes in a hierarchical tree structure using the broadcasting station as an apex; an extension tree obtained by connecting the plurality of other nodes in a hierarchical tree structure using, as an apex, a first root node as any of the nodes included in the base tree; and a topology controller for controlling a topology of each of the nodes belonging to the base tree. The first root node controls the topology of each of the nodes belonging to the extension tree using the first root node as an apex.