Fujitsu Corporation

Jyoei Kamoi

Toshio Shimoe

Takeshi Kawasaki

Kazuo Hajikano

Satoshi Kuroyanagi

Ryuichi Takechi

Satoshi Kakuma

Masami Murayama

Tetsuo Tachibana

Hiroshi Tomonaga

Tomoyuki Yamaguchi

Tadahiro Takase

Teruaki Hagihara

Yuji Kato

Shunji Abe

Toshio Soumiya

Mikio Nakayama

Michio Kusayanagi

Naoki Aihara

Hichiro Hayami

Haruo Mukai

Iwao Tada

Ippei Sawaki

Yoshihiro Uchida

Yuzo Okuyama

Koso Murakami

Kazuhito Yasue

Kazuhiko Kumagai

A system for controlling a bandwidth when receiving and reassembling a consecutive data stream transferred while segmented by AAL1 format cells which enables correct determination of non-P and P formats and reassembly of cells even when error arises in multiple bits including the CSI bit of an AAL1 cell or when adding dummy cells and thereby enabling prevention of a gap in data in a frame, comprising, in a data reassembly unit which reassembles received cells, an 8-cell buffer for storing 8 cells of a cycle of a sequence count (SC) of 0 to 7 and sending the cells out to a later stage after a check unit of a sequence number (SN) field confirms normalcy of the cells and a control unit for control so that the number of P format cells stored in the 8-cell buffer becomes 1 cell when 8 cells are stored in the 8-cell buffer.

System for controlling AAL1 cell bandwidth

To reduce a scale of the circuit, a number of the external terminals, processing steps in developing a firmware, and a scale of the firmware, a line terminator provided in a device for terminating SONET/SDH lines, each having a different line speed, terminates plural lines, each having a different line speed, and includes a clock generator generating a clock corresponding to each line speed, a line switching circuit for specifying one of the plural lines, a selector for outputting data of one of the plural lines, which is specified by the line switching circuit, and a common processing circuit for processing data of the one line output from the selector, according to a clock corresponding to the line speed generated in the clock generator.

Line terminating device

The object of the present invention is accomodating local connectionless information (data that is immediately transferred without establishing a path to a receive side), such as LAN data in a local area network, by an asynchronous transfer mode (ATM) network using a connection-oriented communication system (which makes data transfers after verifying that a path to the receive side has been established), thereby performing efficient, fast routing of connectionless information. A connectionless communication system of the present invention is equipped with connectionless information cell assembly/deassembly means for bi-directional conversion between variable-length connectionless information and fixed-length connectionless cells, routing control means for analyzing a destination address of information in connectionless cells and controlling the routing of the connectionless cells; and an ATM network for connecting the connectionless information cell assembly/deassembly means and the routing control means by a permanent virtual channel serving as a fixed path and connecting the routing control means together by a virtual channel serving as a semi-fixed path, whereby connectionless information is segmented into connectionless cells and the connectionless information is exchanged within the ATM network in connectionless cell units.

Connectionless communication system

The invention concerns an ATM exchange, and is directed in particular to the provision of a cell bandwidth control apparatus for performing bandwidth control for ATM cells sent from the ATM exchange onto the line side. The cell bandwidth control apparatus includes forced empty cell inserting means for forcibly inserting empty cells in a highway connected to an ATM switch. The forced empty cell inserting means inserts forced empty cells in an outgoing highway leading from the ATM switch to a line adapter and thereby limits the line bandwidth of the outgoing highway to within the bandwidth of the line accommodated in the line adapter.

Cell bandwidth control apparatus

A method and device for controlling transfer of cells in an ATM equipment, using the statistical multiplexing effect to control the transfer speed at regular intervals, so as to realize an efficient management and a fine control of the information transfer speed. The cell control device includes a cell transfer control buffer, a cell transfer timing operating unit that performs a desired operation to calculate a cell transfer timing, using a first parameter T and a second parameter X, and a cell transfer control unit that controls the transfer timing of the cell from the buffer, based on the result from the cell transfer timing operating unit, to perform a cell transfer control at a peak rate of X/T in correspondence with a processing rate of the ATM equipment.

Cell transfer control method and cell transfer control device

A plurality of input lines are respectively connected to separate multiplexing units that are connected in cascade by cascading lines. Select signals are transferred in parallel with fixed length packets over the cascading lines. Each separate multiplexing unit is responsive to a select signal received from the cascading line to select one of fixed length packets received over the corresponding input line and the upstream cascading line and output it over the downstream cascading line. The most downstream separate multiplexing unit provides a multiplexed output of the input lines.

Line multiplexing system

A communication system for use with a network for transmitting fixed-length cells from a transmitting terminal via a virtual connection in the network to a receiving terminal. The communication system includes a converting device, connected to the transmitting terminal or the receiving terminal, for performing a bi-directional conversion between a variable-length packet and the fixed-length cells, the transmitting terminal or the receiving terminal outputting the variable-length packet, a buffer capacity monitoring device in the receiving terminal for monitoring a capacity of a buffer in the receiving terminal receiving the fixed-length cells and for outputting an alarm signal at the time of detecting a congestion state of the capacity of the buffer, a congestion state alerting device in the receiving terminal responsive to the alarm signal from the buffer capacity monitoring device for outputting an alert signal to the transmitting terminal, and a traffic transmission control device in the transmitting terminal responsive to the alert signal from the congestion state alerting device in the receiving terminal for controlling a transmission of the fixed-length cells to the receiving terminal.

A device for discriminating timeout comprises an event discrimination unit, a calculation unit, a timing storage unit and a timeout discrimination unit. The event discrimination unit outputs each communication information concerning each communication to the calculation unit, when an event indicating a start of timeout discrimination occurred. The calculation unit calculates a timeout timing for every communication on the basis of the each communication information and the timing in which the event has occurred, and writes the calculated timeout timing into the timing storage unit. The timeout discrimination unit compares the timeout timing read out from the timing storage unit for every communication with the present timing, and discriminates that the timeout has occurred in reference to the communication when the present timing exceeds the timeout timing.

Device and method for discriminating timeout

A communication system for transmitting a fixed-length cell converted from a variable-length information including data and a destination of the data. The system includes a cell assembly/disassembly device for performing bi-directional conversion between the variable-length information and the fixed-length cell, a routing control device for receiving the fixed-length cell converted from the variable-length information by the cell assembly/disassembly device, for analyzing the destination of the data and for controlling a routing of the fixed-length cell based on the analyzed destination, and having an error detecting device for detecting an error of the variable-length information in the fixed-length cell, and a network for connecting the cell assembly/disassembly device and the routing control device by a fixed capacity path and for connecting the routing control device to another routing control device by the fixed capacity path or a variable capacity path.

An Asynchronous Transfer Mode (ATM) cell error processing system includes a plurality of error detectors for respectively detecting predetermined cell errors and for respectively generating decision signals and an error editing unit which is operatively coupled to the error detector and determines, based on the decision signals, whether or not a cell related to the decision signals should be discarded. A buffer, which is coupled to at least one of the error detectors, temporarily stores the cell. An error cell discarding unit, which is coupled to the error editing unit and the buffer, discards the cell from the buffer when the error editing unit determines that the cell should be discarded and relays the cell when the error editing unit determines that the cell should not be discarded.

Asynchronous transfer mode (ATM) cell error processing system

A call admission control system in an asynchronous transfer mode exchange includes a unit for describing attribute parameters of a cell from the subscriber terminal; a unit for calculating, based on the attribute parameters, the average and the dispersion of the traffic speeds of the call; a unit for managing data of the average and the dispersion on each output route and data relating to each subscriber; and a unit for calculating the total average and the total dispersion of the data speeds on the selection output route; and a unit for calculating prediction values of cell abandon rate and end-to-end delay based on the average and the dispersion on the selected output route calculated by the total average and dispersion calculating unit, and for comparing the prediction values with the required service quality of cell discard rate and end-to end delay, for determining whether or not the requesting call may be connected.

Traffic control system for asynchronous transfer mode exchange

A call admission control system in an asynchronous transfer mode exchange includes a unit for describing attribute parameters of a call from the subscriber terminal; a unit for calculating, based on the attribute parameters, the average and the dispersion of the traffic speeds of the call; a unit for managing data of the average and the dispersion on each output route and data relating to each subscriber; and a unit for calculating the total average and the total dispersion of the data speeds on the selected output route; and a unit for calculating prediction values of cell abandon rate and end-to-end delay based on the average and the dispersion on the selected output route calculated by the total average and dispersion calculating unit, and for comparing the prediction values with the required service quality of cell discard rate and end-to-end delay, for determining whether or not the requesting call may be connected.

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Kawasaki, Japan

Jyoei Kamoi