Nippon Telegraph and Telephone Corporation

Inter-university Research Institute Corporation Research Organization of Information and Systems

Shigeo Urushidani

Ichiro Inoue

Nobuaki Matsuura

Michihiro Aoki

Hitoshi Imagawa

Takashi Kurimoto

Takashi Miyamura

Kaori Shimizu

Keisuke Kabashima

Kohei Shiomoto

Hisashi Kojima

Koji Sasayama

Tomonori Takeda

Masahiro Goshima

Jun Nishikido

Rie Hayashi

Koichi Hagishima

The path management controllerrefers to resource informationincluding reservation statuses of working paths and advance reserved paths that are set in every link, so as to calculate a route for setting a new path and set this path in this calculated route. If the route for setting this new path cannot be obtained (1) because of a shortage of residual bandwidth of a link of interest, the path management controllerrefers to the resource reservation informationof working paths and advance reserved paths and calculates an alternative route for another existing path used in the link of interest, and moves this path to the calculated alternative route. On the other hand, if the route for setting this new path cannot be obtained (2) because there is no continuous bandwidth sufficient for setting this new path in the link of interest, the path management controllerrefers to the resource reservation information regarding working paths and advance reserved paths in the link of interest in the resource information, so as to execute the time slot rearrangement.

Path management control method, path management control program, path management controller and path management control system

An optical network has: sections for establishing optical paths; a plurality of optical edge routers for connecting external IP networks to the optical network (); and a plurality of optical cross connects, for connecting the optical edge routers by the optical paths, having switching sections with respect to an optical pulse unit. In the optical network, each of the optical edge routers has both of: (1) an optical network control instance (INSp) for maintaining topology information in the optical network and switching/signaling the optical paths; and (2) an IP network instance (INSi) for maintaining a routing table in each of the external IP networks and activating routing protocols between the external IP networks and the IP network instance. By doing this, it is possible to realize a multi-layer cooperative function and provide highly safe optical networks, etc.

Optical network, optical edge router, program thereof, cut through method, and edge router

A route switching method for switching a route in a core network that accommodates service networks including user node apparatuses by use of a server storing path information that includes, in every time frame, a route for a working path and a route for a backup path to be switched over from the working path, both of the working path and the backup path established between two boundary node apparatuses each of which is located on a boundary between the service network and the core network. The server calculates, in response to the connection request from the user node apparatus, a route for a working path and a route for a backup path, and requests the boundary node apparatus to establish this working path. The server can send the route for the backup path to the boundary node apparatus before a failure occurs in the core network. The boundary node apparatus establishes the working path in response to the establishment request for establishing the working path from the server, and can perform a quick recovery by switching over the working path to the backup path when a failure occurs in the core network.

Route switching method, server, boundary node apparatus, route switching system, and route switching program

A data transfer apparatus and a data transfer system are provided that can reduce the cost of installing communication equipment compatible with each of several dissimilar communication protocols in one exchange office and can reduce the cost of constructing the network. The data transfer apparatus includes a data reception device () that receives packets that comply with dissimilar communication protocols from upstream data transfer apparatuses (and); a content data extraction device () that extracts content data included in the packets; a line selection information storage device () that stores the line selection information for selecting communication lines that comply with dissimilar communication protocols; a line selection device () that selects the communication line compatible with content data based on the line selection information; and a data transfer device () that transfers data to downstream data transfer apparatuses (and) that are connected to the communication line that has been selected by the line selection device.

Data transfer apparatus and data transfer system

A FIFO buffer in which respective portions are controlled in a distributed manner is provided. In the FIFO buffer, a number of loop circuits having delay elements are provided in which respective loop circuits are connected to one another in cascade manner. Additionally provided are a number of traffic control units for controlling the signal traffic between respective neighboring loop circuits. In the case where no signal is fed back to a traffic control unit from the output side and also a new signal is transmitted thereto from the input side, the traffic control unit transmits the new signal to the loop circuit which is on the output side. In the case where any signal is fed back to a traffic control unit from the output side and also a new signal is transmitted thereto from the input side, the traffic control unit again transmits the fed-back signal to the loop circuit which is on the output side and transmits the new signal to the loop circuit which is on the input side. In the case where any signal is fed back to a traffic control means from the output side and also no signal is transmitted thereto from the input side, the traffic control means transmits again the fed-back signal to the loop circuit which is on the output side.

Optical FIFO buffer

A self-routing switch in which a plurality of switching stages, each having a plurality of switching elements, are sequentially connected by substitute links, wherein additional two input terminals and additional two output terminals are provided in each switching element of at least the last plural switching stages of the switch, and the output terminals and input terminals of the same line position between these last plural switching stages are connected by equivalent links, respectively. When information data appended with a destination address and judge times, as routing information, is input into the switch, one of the bits in the destination address is selected as a judge bit on the basis of the judge times, and the output terminal to which the information data is to be output is selected according to the value of the judge bit.

Self-routing switch and its routing method

In a self-routing switch which comprises a plurality of switching stages inserted between pluralities of input and output lines and cascade-connected by pluralities of input and output links, each switching stage includes a plurality of cascade-connected store/switch elements. Each store/switch element of each switching stage outputs an information data input thereto from the corresponding input link to the corresponding output link or shifts the input information data through a predetermined number of cascade-connected elements and outputs it to the corresponding output link, in accordance with a portion of routing information contained in the input information data, which portion corresponds to the switching stage.

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Tokyo, Japan

Shigeo Urushidani