Nippon Telegraph and Telephone Corporation

Seisho Yasukawa

Eiji Oki

Naoaki Yamanaka

Koji Sugisono

Masayoshi Nabeshima

Masanori Uga

Mika Ishizuka

Naoki Takaya

Hiroshi Inoue

Hiroyuki Kitada

Takafumi Okuyama

Yasuharu Kaneko

Shingo Okada

Toshiaki Tsuchiya

Kojun Koshiji

Kenichi Endo

Takuya Tojo

Kohei Shiomoto

Takuma Tsubaki

Saburo Seto

A control device that controls a bit rate selectable by a client terminal in a video distribution network in which video data is distributed includes a database configured to store distribution information, band allocation information, and distribution system information, the distribution information containing information on video data in a distribution system, the band allocation information containing an allocated band of each session in which the distribution system performs video distribution, and the distribution system information containing a channel band of the distribution system, and a control unit configured to receive a viewing request from the client terminal, calculate an available band in the distribution system with reference to the database, and determine a maximum bit rate selectable by the client terminal based on the available band and one or more bit rates of video data corresponding to the viewing request.

Control apparatus, control method and program

A topology design device for an optical transmission network includes a memory; and a processor to determine a bypass target area as an area to which a bypass route is to be added in the network, the area indicating a region surrounded by nodes and edges, based on an area demand, namely a total value of a demand for communication to be performed via an edge, by referencing a topology management database storing information regarding nodes, edges, and areas in the network, and a demand management database storing demands in the network; and exclude a node from nodes constituting the bypass target area and determining a bypass route from the nodes from which the node has been excluded, based on a node demand, namely a total value of a demand for which each node serves as a start or end point of the demand, by referencing the databases.

Topology design apparatus, topology design method and program

A local wavelength defragmentation apparatus performs wavelength defragmentation for at least one wavelength path passing through a target link in an optical transmission network. The local wavelength defragmentation apparatus includes a reallocation rank determination unit configured to calculate a remaining time from a present time to an abolition timing for each of the at least one wavelength path and determine rank for wavelength reallocation of the at least one wavelength path based on the remaining time; and a reallocation number determination unit configured to calculate utilization of at least one reallocatable wavelength number for each of the at least one wavelength path according to the rank, and determine a wavelength so that a wavelength of the wavelength number having the highest utilization is reallocated.

Local wavelength defrag apparatus, local wavelength defrag method and program

A demand prediction apparatus allows for a prediction with a variation in terms of demand by acquiring, out of changes in demand in a first time period, changes in the demand in a second time period which is a part of the first time period acquiring changes in the demand in third time periods, which is a plurality of time periods excluding the second time period within the first time period, for each of the third time periods having different lengths, identifying, for combinations of a plurality of trend patterns and the third time periods, parameters of the corresponding plurality of trend patterns such that a value of a trend pattern of the plurality of trend patterns is equal to the demand at a certain time point in the first time period, evaluating suitability with the changes in the demand in the second time period for each of the plurality of trend patterns for each of the combinations in which a parameter of the parameters is identified, and selecting one or more trend patterns from among the plurality of trend patterns for each of the combinations based on evaluation results.

Demand prediction apparatus, demand prediction method and program for predicting a demand of a path on a network using selected trend patterns

A control apparatus for registering a connection state between component devices constituting a distributed optical transmission apparatus in a database includes: a device setting unit which performs setting such that light is output from a component device that is a connection source; and a registration processing unit which acquires a light reception level of each port in each component device on a side receiving the light, identifies a port having a light reception level higher than light reception levels of other ports, and registers a component device having the identified port and the identified port in the database as a connection destination of the component device that is the connection source.

Control apparatus, connection status registration method and program

A control apparatus includes an optical wavelength change control unit that specifies, in response to a request to change a wavelength band of a first optical wavelength path used by a first transmission apparatus and a second transmission apparatus to a wavelength band of a second optical wavelength path, a first route between routers which is affected by the request and a service which uses the first route and that specifies a second route between the routers which detours the specified service; a router control unit that transmits a request to detour the specified service to the second route, to a start-point router and an end-point router on the first route; and a transmission apparatus control unit that transmits a request to change the wavelength band of the first optical wavelength path to the wavelength band of the second optical wavelength path, to the first transmission apparatus and the second transmission apparatus.

Control apparatus and control method

A system control device that transmits a manifest file describing information necessary for acquiring video data to a viewing client in a system that performs distribution of the video data via a network includes: generation means for generating the manifest file on the basis of at least one of identification information indicating a viewer attribute, a time zone, and a state of the system according to a prescribed control policy; and transmission means for transmitting the manifest file generated by the generation means to the viewing client.

System control apparatus, system control method and program

A quality information collecting system acquiring video data distributed in response to a viewing request and collecting quality-related information regarding video viewing from a viewing client playing back a video includes a quality information control functional unit configured to determine whether or not to request the viewing client having made a viewing request to report quality-related information, based on a network communication situation in which the video data is distributed, and a quality information collecting and analysis functional unit configured to receive, in accordance with a determination of the quality information control functional unit, the quality-related information transmitted from the viewing client.

Quality information collection system, quality information collection method and program

A computer executes a first determination procedure determining a first link which at least partially overlaps a disaster area representing a range reached by an influence of a predetermined disaster, among links constituting a network, a second determination procedure determining a second link which at least partially overlaps a road area representing a range of a road width of a predetermined road used to recover from the disaster, among the links constituting the network, a route search procedure searching for a plurality of routes from a start point node to an end point node constituting the network, a grouping procedure grouping the plurality of routes searched for by the route search procedure into groups depending on a first parameter value that is based on the first link included in the routes, a computing procedure computing, for each of the plurality of routes searched for by the route search procedure, a second parameter value that is based on the first link and the second link included in the routes, and a selecting procedure selecting a predetermined number of routes among one or more routes grouped into the same group on the basis of the second parameter value computed by the computing procedure for each of the groups grouped by the grouping procedure.

Route calculation method, route calculation apparatus and program

A method of establishing a multicast transfer route is disclosed that can reduce the cost of entire route under a constraint on delay incurred between starting point and ending points. The method includes the steps of: computing the shortest route with respect to delay connecting the starting point and the plural ending points based on measurement result; computing delay from a node on the shortest route to each ending point and the greatest delay; removing, if the greatest delay satisfies a delay condition, the greatest-cost route from the shortest route in accordance with selection criteria effective for cost reduction; dividing the multicast transfer route into two route trees; and establishing separately computed route as a complementary route that complement the removed route for connecting the two route trees. A method of multicast label switching for realizing the above method is also disclosed. A multicast label switching route is established using hierarchical labels by establishing a common multicast label switching route using a first layer label and establishing plural partial multicast label switching routes for subgroup destinations using lower layer labels. A relay node recognizes the hierarchical labels thereby to label-switch using all hierarchical labels.

Method of setting multicast transfer route and method of multicast label switching for realizing the same

A multicast communication path calculation method is disclosed which includes the steps of: obtaining minimum delay paths from a source node to each destination node; selecting, as candidate nodes of a rendezvous point node, nodes on one of the obtained minimum delay paths; for each candidate node, calculating minimum delay paths from the candidate node to each destination node, and obtaining a difference between the maximum value and the minimum value among delays of the calculated minimum delay paths; selecting, as the rendezvous point node, a candidate node by which the difference is smallest; and outputting a minimum delay path from the source node to the rendezvous point node and minimum delay paths from the rendezvous point node to each destination node.

Multicast communication path calculation method and multicast communication path calculation apparatus

Multicast transfer route setting method, and multicast label switching method for implementing former method

An ATM switch includes a first stage, a second stage and a third stage each of which stages includes at least one basic switch, wherein the first stage, the second stage and the third stage are connected. The basic switch includes a part which refers to time information written in a header of an input cell and switches cells to an output port in an ascending order of the time information. In addition, the ATM switch includes a cell distribution part in the basic switch of the first stage. The cell distribution part determines a routes of a cell to be transferred such that loads of routes within the ATM switch are balanced. The ATM switch further includes an adding part which adds arriving time information to an arriving cell as the time information.

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Tokyo, Japan

Seisho Yasukawa