Fujitsu Corporation

Tetsuo Nishino

Osamu Isono

Tetsuo Tachibana

Ryuji Hyodo

Eisuke Iwabuchi

Toshimasa Fukui

Osamu Sekihata

Katsumi Oomuro

Kenji Tanaka

Hiroyuki Hatta

Susumu Eda

Reiko Norizuki

Naoyuki Miyamoto

Reiko Furuya

Shunji Abe

Tatsuru Nakagaki

Kazuo Hajikano

Hichiro Hayami

Emi Hata

Koso Murakami

Tsuyoshi Yoneta

Nakaba Yuhara

Katsumi Omuro

Hirokazu Minou

Hiroko Okamura

Yasunori Yamatani

A picture distribution service system carries out a distribution control of picture information service in a broadband transit switching network having a hierarchical structure. The system comprises a plurality of transit switches for switching transit lines through which picture information is transmitted from a source and distributed by a center switch, a first trunk part provided for each of the transit switches for distributing the picture information from the center switch to the transit lines, a plurality of subscriber switches for switching subscriber lines through which the picture information from each of the transit lines is transmitted to a plurality of subscriber terminals, and a second trunk part provided for each of the subsriber switches for distributing the picture information from each of the transit switches to the subscriber lines.

Picture distribution service system

An ATM multiplex transmission system including AAL processing units, an ATM cross connection processing unit, and a plurality of lines connected to the same, wherein the system has test equipment formed in it, the test equipment being formed as a particular cell generating unit and a routing information setting unit in at least one of the line corresponding points which the ATM cross connection processing unit has at the portions connecting with the lines. When a routing test is performed in the system, the VPI and the VCI designating the route are given from the outside as the routing information.

ATM multiplex transmission system having test equipment

In a congestion control system for an interface between a PBX and an ATM multiplexing transmission unit connected to a network via an ATM transmission line, a congestion detecting unit detects a congested state in which the ATM transmission line is congested with traffic. A control unit inhibits a call from the PBX from being sent to the ATM transmission line via the ATM multiplexing transmission unit when the congestion detecting unit detects the congested state.

System and method for controlling interface between PBX and ATM

An amount-of-data identifying portion identifies the amount of data transmitted by referring to a specific portion in the upper layers of the information transmitted from the terminal of a LAN, and a bandwidth control line monitor portion calculates the band which is necessary for communication. Communication between LANs is executed through the number of wide area network interface portions which is determined on the basis of the calculated band. In the case that the communication is performed after securing the band corresponding to the traffic characteristics (transfer speed, etc.) declared to the network, the amount-of-data identifying portion identifies the amount of data transmitted by referring to a specific portion in the upper layers of the information transmitted from the terminal of a LAN, a traffic characteristics calculator calculates the traffic characteristics on the basis of the amount of data transmitted, a traffic characteristics declaring portion declares the calculated traffic characteristics to the network, and the network communicates on the basis of the declared traffic characteristics.

Communication apparatus for communicating between LANS through a wide

In an ATM cell assembling and disassembling method for a communications network having first and second communications nodes, HDLC data is transferred from a first terminal to the first communications node via a first transmission line, the HDLC data conforming to an HDLC format. It starts to assemble, in the first communications node, at least one cell from the HDLC data when data which is contained in the HDLC data and equal to one cell has been received. Then the above at least one cell of ATM data is transferred from the first communications node to the second communications node. Disassembly is started, in the second communications node, of the above at least one cell of ATM data to thereby generate original HDLC data when a fluctuation compensation time has elapsed after a first cell of ATM data among the above-mentioned at least one cell of ATM data is received by the second communications node. The fluctuation compensation time is based on a maximum fluctuation time of a route connecting the first and second communications nodes to each other as well as a bit rate of the first transmission line. Finally, the original HDLC data is transferred to a second terminal from the second communications node via a second transmission line.

ATM cell assembling and disassembling system and method

An ATM exchange system includes a unit for detecting management cells from among multiplexed input ATM cells, and a path creating unit dedicated to the detected management cell. The path creating unit is activated each time the management cell detecting unit detects the management cell, and thus the management cell is transferred to the corresponding outgoing line without loss in the exchange, and can be transferred thereto before a user ATM cell.

ATM exchange system

A synchronization circuit for ATM cells transferred in an ATM communication system, wherein the synchronization circuit receives and holds in a bit serial manner the input bit trains constituting the received ATM cells by a shift register unit, performs a CRC operation in a bit serial manner on the held input bit trains by a continuous CRC arithmetic unit in accordance with a simplified CRC operation process different from the usual CRC operation process, and performs the necessary synchronization control upon receiving the CRC arithmetic operation result at a synchronization control unit, thereby enabling CRC arithmetic operations to be performed continuously and by simple hardware on the headers in the ATM cells.

Synchronization circuit

An ATM communication system including an ATM switching network which includes a plurality of ATM exchanges and controls exchanges among a plurality of terminal equipment and a management apparatus which manages the traffic in the ATM switching network; the ATM switching network including a notifying unit which notifies the terminal equipment of the allocable bandwidth which can be used in accordance with the amount of traffic in the ATM switching network; when the notified allocable bandwidth is a bandwidth which can be used for their communication, the terminal equipment starting the communication in the range of that bandwidth.

ATM communication system with optimal traffic control by changing the

A change-back system is designed for an asynchronous transfer mode network in which a rerouting path is set to replace an original path when a fault is generated in the original path within the network, which network includes a plurality of communication nodes which are coupled via lines and communicate information in the form of cells, and the original path and the rerouting path couple first and second communication nodes within the network. The change-back system makes a change-back process to change the path used from the rerouting path to the original path when the fault is restored. The change-back system includes a first circuit for detecting a restoration of a fault in the original path, a second circuit for transmitting a cell from the first communication node to the second communication node via each of the rerouting path and the original path when the restoration of the fault is detected, prior to making the change-back process, and for measuring a first time it takes for the cell to travel through the rerouting path and a second time it takes for the cell to travel through the original path, and a third circuit for calculating a guard time which is a difference between the first and second times and for delaying transmission of a cell from the second circuit to the original path after the restoration of the fault, so that the cell after the restoration of the fault is transmitted to the original path at least after a time which corresponds to the difference from a time when a cell is last transmitted to the rerouting path immediately before the fault is restored.

Rerouting and change-back systems for asynchronous transfer mode network

A method of transmits HDLC data which is in conformance with a high-level data link control procedure via an asynchronous transfer mode network. The method includes the steps of deleting at least flags from the HDLC data before assembling ATM cells which are transmitted via the asynchronous transfer mode network, disassembling the ATM cells which are received via the asynchronous transfer mode network, and inserting at least flags to the disassembled ATM cells to restore the original HDLC data.

Method and system for transmitting HDLC data via ATM network

A routing method routes cells which are transferred through one of a plurality of paths within an asynchronous transfer mode (ATM) switching system selected by routing information. The routing method includes the steps of adding first routing information to incoming cells at an input stage of the ATM switching system when supplying the cells to the ATM switching system, generating a route switching confirmation cell in response to a route switching instruction and for adding second routing information to incoming cells thereafter so as to supply the route switching confirmation cell and the cells added with the second routing information to the ATM switching system. The second routing information is different from the first routing information and is determined by the route switching instruction, comparing routing information. The method also includes the cells with the second routing information at an output stage of the ATM switching system in response to the route switching instruction, and outputting each cell from the ATM switching system having routing information different from the second routing information as it is. The method also includes temporarily storing each cell from the ATM switching system having routing information identical to the second routing information and reading out and outputting the stored cell after the route switching confirmation cell is output from the ATM switching system.

Routing method and routing system for switching system having a

A self-routing switching system connected between input highways and output highways, includes conversion modules, doubled SRM networks, output modules, and first and second selectors. Normally, one of the SRM networks is connected between the conversion modules and output modules through the first and second selectors. When a request to switch the active network to the other SRM network is received, the first and second selectors switch connections to the conversion modules and output modules so that the other SRM network is connected between the conversion modules and output modules. Before actually switching the connections, it is determined whether or not all cells have been discharged from the active SRM network.

Self-routing switching system having dual self-routing switch module

A transmission control system in which terminals are connected to an ATM switching network, has a table circuit registering virtual channels presently formed in the ATM switching network in a management table, and a retrieval part for receiving a communication request from one of the terminals and for determining whether or not the management table registers a virtual channel corresponding to the communication request. Data output from one of the terminals is transferred to a different one of the terminals addressed by the communication request through the virtual channel corresponding to the communication request and corresponding two of the terminal adapters, when the retrieval part determines that the management table has the virtual channel corresponding to the communication request. A virtual channel setting part registers the virtual channel corresponding to the communication request in the management tabele, when the retrieval processor determines that the management table does not have the virtual channel corresponding to the communication request. Data output from the one of the terminals is transferred to the different one of the terminals addressed by the communication request through the virtual channel registered in the management table by the virtual channel setting part.

System for controlling data transmission in ATM switching network

An information distribution system includes a node station and a plurality of terminal devices connected through transmission lines with the node station. The node station includes a distribution information storage unit for storing information which is to be distributed to the plurality of terminal devices, and a re-transmission request response unit for re-transmitting information in question in response to requests from the plurality of terminal devices. Each of the terminal devices includes an error checking unit for checking transmission failure in the data transmission based on the received information. The transmitted information is divided into a plurality of blocks, and, after the completion of reception of all block-form information, a re-transmission of information is requested, and based on this request, a re-transmission of information is carried out.

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Kawasaki, Japan

Tetsuo Nishino