Fujitsu Corporation

Ryuji Hyodo

Katsumi Oomuro

Kenji Tanaka

Osamu Sekihata

Hiroyuki Hatta

Susumu Eda

Tetsuo Nishino

Reiko Norizuki

Tetsuo Tachibana

Osamu Isono

Eisuke Iwabuchi

Toshimasa Fukui

Reiko Furuya

Naoyuki Miyamoto

Tatsuru Nakagaki

Tsuyoshi Yoneta

Nakaba Yuhara

Hirokazu Minou

Katsumi Oomura

Katsumi Omuro

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 ATM multiplex transmission system including an ATM adaptation layer (AAL) processing unit, an ATM cross connection processing unit having a switch and FIFO memories connected to the incoming and outgoing sides, and dummy load cell generating units which forcibly write dummy load cells in the incoming FIFO memories or outgoing FIFO memories, the writing of the dummy load cells being used to execute a load test on the FIFO memories.

A method for supervising and controlling ATM traffic, which uses idle cells transferring traffic information to manage a network, comprising steps of a first step for mapping traffic information in the information field of an idle cell and transferring said idle cell to other communication nodes, a second step for performing the operation of traffic control in accordance with the contents of said traffic information included in said idle cell on the receiving side of said other communication nodes, and a third step for assembling a new idle cell including said traffic information of received idle cell and/or new traffic information on said receiving side of communication nodes and transferring said new idle cell from said receiving side of communication nodes to other communication nodes.

Apparatus and a method for supervising and controlling ATM traffic

An apparatus for supervising and controlling ATM traffic, and which collects traffic information, including a cell detecting unit for outputting a cell detecting signal whenever detecting a user information cell flowing through an ATM switch unit, an idle cell detecting unit for outputting an idle cell detecting signal whenever detecting an idle cell flowing through an ATM switch unit, a cell counting unit for counting the cell detecting signals output from the cell detecting unit, an idle cell counting unit for counting the idle cell detecting signals output from the idle cell detecting unit, an idle cell rate detecting unit for detecting an idle cell rate from both counts output from the cell counting unit and the idle cell counting unit at regular intervals, and a control unit for performing the operation of traffic control in accordance with the idle cell rate provided from the idle cell rate detecting unit at regular intervals.

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 apparatus for setting a communication path in ATM communication, comprises: communication path control unit for indicating a communication path test before starting communication; test cell assembling unit for assembling test cells that consist of a series of cells each of which has a sequential number for detecting test cell discard and has the higher cell discard priority (CLP=1); communication path setting unit for setting up the communication path and replacing transmit idle cells with the test cells; and cell-discard detecting unit for comparing the sequential number contained in received test cells with the number of the received test cells and thereby outputting a communication path setting enable or disable control signal.

Apparatus and a method for setting a communication path

An apparatus for supervising and controlling ATM traffic, and which collects traffic information, comprises a cell detecting unit for outputting a cell detecting signal whenever detecting a user information cell flowing through an ATM switch unit, an idle cell detecting unit for outputting an idle cell detecting signal whenever detecting an idle cell flowing through an ATM switch unit, a cell counting unit for counting the cell detecting signals output from the cell detecting unit, an idle cell counting unit for counting the idle cell detecting signals output from the idle cell detecting unit, an idle cell rate detecting unit for detecting an idle cell rate from both counts output from the cell counting unit and the idle cell counting unit at regular intervals, and a control unit for performing the operation of traffic control in accordance with the idle cell rate provided from the idle cell rate detecting unit at regular intervals.

A fault notifying system notifies a fault in an asynchronous transfer mode (ATM) network to at least one data terminating equipment (DTE). The fault notifying system includes a network interface coupled to the ATM network for outputting an alarm indication signal (AIS) when a fault is generated in the ATM network. An ATM crossconnect part generates an AIS cell having a predetermined signal format in response to the AIS. An adaptation layer processing part forms ATM cells, disassembles ATM cells and outputs a data circuit-terminating equipment not ready (DNR) in response to the AIS cell. A terminal interface coupled to the DTE notifies the fault in the ATM network to the DTE in response to the DNR. The AIS cell has a cell format identical to an ATM cell format but has predetermined information in a specific part of the ATM cell format to distinguish the AIS cell from the ATM cell.

Fault notifying system for asynchronous transfer mode communication

In a VPI and VCI assignment system in an ATM system having a plurality of nodes and terminals, each of the nodes including a conversion unit which generates ATM cells from data sent from one of the terminals, and a node management unit which manages a corresponding one of the nodes, a management unit assigns VPIs and VCIs to calls and manages information concerning VPIs and VCIs currently assigned to the calls and idle VPIs and VCIs. An assignment requesting unit, which is provided in each of the nodes and connected to the management unit, requests the management unit to assign a VPI and a VCI to a call received from one of the terminals. An assignment cancelling unit, which is provided in each of the nodes and connected to the management unit, requests the management unit to cancel the VPI and VCI assigned to the call in response to an end of a communication related to the call.

VPI and VCI assignment system in ATM system

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 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.

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Kawasaki, Japan

Ryuji Hyodo