Fujitsu Corporation

Naoki Aihara

Shuji Yoshimura

Tomoyuki Yamaguchi

Tadashi Hoshino

Satoshi Kakuma

Masami Murayama

Yasuhiro Aso

Jyoei Kamoi

Hichiro Hayami

Naoki Fukuda

Iwao Tada

Yoshihiro Uchida

Mikio Nakayama

Hiroshi Miyake

Nobuhiko Eguchi

Takashi Tabu

Kazumasa Sonoda

Kazuhiko Kumagai

Kazuhito Yasue

Hiroyuki Kudou

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

A method and system including ATM switching equipment provided for switching between a working channel and a protection channel in an ATM network. The method and system include the following processes: In each cell for transmission providing an indication of whether the cell belongs connection currently in a working state via a working channel; cells are duplicated on each connection basis; the duplicated cells are transmitted simultaneously on both a working channel and a protection channel; and valid cells are selected from received cells according to the indication in each cell indicating whether the relevant connection is currently in a working state.

ATM switching system and method for switchover between working channel and protection channel in an ATM network

A supervision control system for an ATM cell switching system counts the number of cells transmitted from a subscriber in a predetermined duration unit, attaches a sign to the cells when the counted value exceeds a predetermined value, and discards the cells to which the sign is attached when a buffer does not have enough capacity during a cell multiplexation.

Supervision control system

The first input route information with a virtual path identifier, a virtual channel identifier and a line identifier set in the header of an input cell is compressed, and a base address with a lower number of bits than the input route information is generated from a part of the second input route information selected by the compression using a first conversion table. Then, third data consisting of both the base address and a part of the second input route information other than the part of the second input route information selected by the compression are generated, and the third data are converted to a routing tag using a second conversion table.

Multiline-correspondent cell header conversion apparatus and method

An apparatus for pass control of transmission cells for preventing cells having headers including a specific pattern of multi-bit error from being erroneously transmitted. The pass control apparatus is operated by a method comprising (i) a step of monitoring a communication quality of each received frame; (ii) a step of temporarily buffering one monitored frame's worth of cells for each frame; (iii) a step of determining whether or not the communication quality of the monitored frame exceeds a predetermined threshold level; and (iv) a step of erasing all of the cells including one-bit error and multi-bit error in their headers from one frame's worth of buffered cells when the communication quality deteriorates exceeding the predetermined threshold level, while passing the buffered cells as they are when it does not exceed the threshold level.

Method and apparatus for achieving pass control of transmission cells

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

An identifier translation apparatus is provided that does not require a prohibitively large memory capacity and that is simple in construction and capable of increasing the speed of processing. Using an address consisting of a VPI and the high-order 6 bits of a VCI, a first-stage table is read to retrieve a block number, and using an address consisting of the retrieved block number and the low-order 6 bits of the VCI, a second-stage table is read to retrieve a routing tag. The routing tag is then appended to a cell.

Identifier translation apparatus

A method of testing an ATM exchange having a redundant structure that includes an active system and a standby system includes the steps of transmitting a test cell from a testing device to both the active system and standby system, causing the test cell to pass through ATM switches in each of the active and standby systems, returning the test cell that has passed through the ATM switches of both systems to the testing device, and conducting a test of the ACT switches in the active and standby systems by comparing data contained in the transmitted test cell with data contained in a test cell received from the active system or standby system.

ATM exchange and method of testing same

A police system of ATM exchange comprises an ATM exchange for exchanging the ATM cells, and an input cell speed limiting unit disposed in an input side of the ATM exchange and having a plurality of elastic buffers with a read speed equivalent to a band designated to each of a plurality of subscribers accommodated in the exchange, the elastic buffers being in accordance with the subscribers, the input cell speed limiting unit being arranged to limit the speeds of cells which are transmitted from each of the subscribers to the exchange to the band designated to each of the subscriber. The ATM exchange can completely manage and restrict the band of a line. Even if a congestion state takes place instantaneously due to an excessive cell flow, it does not affect calls which are in compliance with a predetermined band.

Police system of ATM exchange

It is determined whether or not a passing cell is a cell to be measured. If yes, a signal synchronous with the passing cycle of the cell is generated by a synchronous signal generator. The synchronous signal is digitally processed by a digital signal processor. Thus, each parameter related to the number of passing cells is obtained by converting the analysis based on the time axis to the area analysis based on the frequency axis.

Passing cell monitoring device operated using an ATM switching unit

A virtual channel converter converts a virtual path identifier and a virtual channel identifier, e.g. in a twenty-eight (28) bit frame, attached to the header part of an incoming ATM cell on an input highway to an ATM switcher to identifiers to be attached to an outgoing ATM cell on an output highway capable of fully supporting all the combinations, two hundred fifty-six (256) for example, of a virtual path identifier and a virtual channel identifier no matter where the virtual path identifier and the virtual channel identifier are located in the twenty-eight (28) bit frame. The virtual channel converter comprises a plurality of identifier comparator units and a controller. Each of the identifier comparator units has an input identifier memory for storing an identifier attached to an ATM cell and a comparator for comparing the identifiers of an incoming ATM cell with the identifiers stored in the input identifier memory. The controller instructs respective input identifier memories to store all the values of identifiers attached to incoming ATM cells from a user to a switcher on a one-to-one basis.

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Kawasaki, Japan

Naoki Aihara