Abstract: It is an object to provide a communication terminal capable of determining a cluster formation so as to promptly perform addition of a participant terminal, while maintaining the quality of a stream relay path. Cluster monitoring terminal (430) is an apparatus to determine a cluster formation in a network performing packet transfer according to terminal relay-type multipoint communication, and includes: a cluster quality calculation section (432) for acquiring cluster quality representing a small loss in a packet to be received, per a cluster; a cluster sustainability calculation section (433) for acquiring cluster sustainability representing ease of acceptance of a participant terminal, per a cluster; and cluster division/integration analysis section (434) for determining cluster division with respect to a cluster having low cluster quality, and determining integration with other cluster with respect to a cluster having high cluster quality and low cluster sustainability.

Abstract: A network delay estimation apparatus capable of creating a metric tree with high accuracy and in a short time. Network delay estimation apparatus (302) includes first-round measurement target node selection section (306) that selects one pair or a plurality of pairs of nodes located at a long distance from each other from a known metric tree as first-round measurement target nodes and measures a distance from an arbitrary node, second-round measurement target node selection section (310) that selects a node whose distance from the arbitrary node is estimated to be short as a second-round measurement target based on the distance and a known metric tree and measures a distance from the arbitrary node, and an optimum tree processing section (314) that creates a network metric tree including the arbitrary node based on the distance and the known metric tree.

Abstract: After a delivery tree is reorganized by a local processing, all terminal devices can recognize, in a short time, a delivery route as changed. In a local one of the terminal devices, if the local terminal device is a source node and further if the load of the CPU in any one of nodes exceeds a threshold value or the available band of the circuit line between nodes exceeds a threshold value, then a delivery tree organizing unit (462) determines nodes that receive a packet via such nodes and reselects a delivery route of the determined nodes. A packet structure modifying unit (464), if the local terminal device is the source node, modifies the header of a packet in accordance with delivery route information stored in a delivery route database (412). The packet structure modifying unit (464) then instructs, in accordance with the description of the header, a packet replicating unit (426) on a number of packet replicas and on the transmission destination of the packets.

Abstract: A terminal apparatus minimizes traffic congestion by reducing end-to-end delay and maximizes the bandwidth available in shared N-tree ALM nodes. In this terminal apparatus, an optimal stream path information table stores N-tree session information for all nodes. A server forwarding table stores bandwidth-fair ALM route information for all nodes in a specific N-tree session. An ALM forwarding table constructor updates N-tree session information stored in an optimal stream path information table using network metrics and heuristic rules stored in a heuristic rule database, executes ALM_N-tree algorithm using updated N-tree session information, and thereby generates bandwidth-fair ALM route information.

Abstract: It is an object to provide a communication terminal capable of determining a cluster formation so as to promptly perform addition of a participant terminal, while maintaining the quality of a stream relay path. Cluster monitoring terminal (430) is an apparatus to determine a cluster formation in a network performing packet transfer according to terminal relay-type multipoint communication, and includes: a cluster quality calculation section (432) for acquiring cluster quality representing a small loss in a packet to be received, per a cluster; a cluster sustainability calculation section (433) for acquiring cluster sustainability representing ease of acceptance of a participant terminal, per a cluster; and cluster division/integration analysis section (434) for determining cluster division with respect to a cluster having low cluster quality, and determining integration with other cluster with respect to a cluster having high cluster quality and low cluster sustainability.

Abstract: A multicast communication apparatus for receiving and forwarding data via a network among a plurality of nodes. The apparatus has: a receiving section that receives the data from a source node; a routing table that stores route information of the data including the source node and a destination node of the data; a forwarding section that forwards the data to a next destination node according to the route information of the routing table; a hop length table that includes a hopping number of the data forwarded from the source node to the next destination node; and a mixing processing section that performs mixing processing of data received from another node. The mixing processing section performs the mixing processing according to the hopping number in the hop length table.

Abstract: Disclosed is a communication channel building device which can guarantee a fair bandwidth allocation and exhibit a preferable perception AV quality in an ALM application. A transfer table building controller controls building of a distribution type optimal channel table over a plurality of communication nodes. A group constructor distributes communication nodes to a group dedicated for a specific source in accordance with the communication node display resolution and the content type and assigns a priority to the group for the specific source. A bandwidth allocator temporarily allocates a bandwidth which can be used for a logic stream between communication nodes. A transfer table constructor builds a distribution type optimal channel table according to the priority of the group for the specific source.

Abstract: A control device according to the present invention comprises a receiving unit which receives, in the network, a multi-address message transmitted from each of the terminal devices, a determining unit which determines whether or not the received multi-address message is to be translated into a unicast message to be transmitted to a specified terminal device, based on information contained in the multi-address message, the specified terminal device being included in the terminal devices, a translating unit which translates the multi-address message into the unicast message when the determining unit determines that the multi-address message is to be translated, and a transmitting unit which transmits the unicast message to the specified terminal device.

Abstract: The invention generally relates to a path constructing device and a path constructing method that can be applied to an AV conference system having different network and resource environments, and a plurality of nodes, and that dynamically allocate resources by giving priority levels and optimizing. It is possible for this new technique to dynamically allocate resources by giving priority levels and optimizing based on AV mixing (MCU) abilities, encoding and decoding abilities, participant screen layout options, and conference events to construct AV paths. This technique is suitable for a real-time AV conference system that can optimize given AV processes and network resources by reflecting the dynamic needs of users.

Abstract: A network delay estimation apparatus capable of creating a metric tree with high accuracy and in a short time. Network delay estimation apparatus (302) includes first-round measurement target node selection section (306) that selects one pair or a plurality of pairs of nodes located at a long distance from each other from a known metric tree as first-round measurement target nodes and measures a distance from an arbitrary node, second-round measurement target node selection section (310) that selects a node whose distance from the arbitrary node is estimated to be short as a second-round measurement target based on the distance and a known metric tree and measures a distance from the arbitrary node, and an optimum tree processing section (314) that creates a network metric tree including the arbitrary node based on the distance and the known metric tree.

Abstract: After a delivery tree is reorganized by a local processing, all terminal devices can recognize, in a short time, a delivery route as changed. In a local one of the terminal devices, if the local terminal device is a source node and further if the load of the CPU in any one of nodes exceeds a threshold value or the available band of the circuit line between nodes exceeds a threshold value, then a delivery tree organizing unit (462) determines nodes that receive a packet via such nodes and reselects a delivery route of the determined nodes. A packet structure modifying unit (464), if the local terminal device is the source node, modifies the header of a packet in accordance with delivery route information stored in a delivery route database (412). The packet structure modifying unit (464) then instructs, in accordance with the description of the header, a packet replicating unit (426) on a number of packet replicas and on the transmission destination of the packets.

Abstract: Disclosed is a communication channel building device which can guarantee a fair bandwidth allocation and exhibit a preferable perception AV quality in an ALM application. A transfer table building controller (316) controls building of a distribution type optimal channel table over a plurality of communication nodes. A group constructor (308) distributes communication nodes to a group dedicated for a specific source in accordance with the communication node display resolution and the content type and assigns a priority to the group for the specific source. A bandwidth allocator (322) temporarily allocates a bandwidth which can be used for a logic stream between communication nodes. A transfer table constructor (328) builds a distribution type optimal channel table according to the priority of the group for the specific source.

Abstract: A terminal apparatus is provided that minimizes traffic congestion by reducing end-to-end delay and maximizes the bandwidth available in shared N-tree ALM nodes. In this terminal apparatus, an optimal stream path information table (204) stores N-tree session information for all nodes. A server forwarding table (202) stores bandwidth-fair ALM route information for all nodes in a specific N-tree session. An ALM forwarding table constructor (218) updates M-tree session information stored in an optimal stream path information table (204) using network metrics and heuristic rules stored in a heuristic rule database (206), executes ALM_N-tree algorithm using updated N-tree session information, and thereby generates bandwidth-fair ALM route information.

Abstract: A multicast communication apparatus for receiving and forwarding data via a network among a plurality of nodes. The apparatus has: a receiving section that receives the data from a source node; a routing table that stores route information of the data including the source node and a destination node of the data; a forwarding section that forwards the data to a next destination node according to the route information of the routing table; a hop length table that includes a hopping number of the data forwarded from the source node to the next destination node; and a mixing processing section that performs mixing processing of data received from another node. The mixing processing section performs the mixing processing according to the hopping number in the hop length table.

Abstract: A player which is capable of playing a video data of low bit rate format, e.g., DVD-VR format, can not play a video data of high bit rate format, e.g., BD-RE format unless the video data is transcoded. Transcoding of video data generally requires a large size storage area. Based on an original navigation information for the video data of high bit rate format, a predictive navigation information for the video data of low bit rate format is generated. Using the original and predictive navigation information, the transcoding is done by sections.