Hitachi, Ltd.

Hitachi Communication Systems, Inc.

Hitachi Communications Systems, Inc.

Tatsuo Mochinaga

Kenji Kawakita

Masashi Hiraiwa

Satoru Inazawa

Akihiko Takase

Atsuo Hatono

Kaori Kawabata

A cell/packet assembly and disassembly apparatus is provided for efficiently connecting a line in a line switching system to an ATM network or a packet network, without causing congestion, to transmit and receive cells or packets therebetween. The cell/packet assembly and disassembly apparatus, upon detecting a call setting request outputted from a line switch board in response to a call originated from a terminal, starts cell assembly and cell disassembly of user information transmitted and received between a channel on a line in the line switching system corresponding to the call setting request and a virtual channel on the ATM network assigned to the channel. Also, when detecting a call setting request outputted from a predetermined virtual channel in the ATM network, the packet or cell assembly and disassembly apparatus starts cell assembly and cell disassembly of user information transmitted and received between the virtual channel on the ATM network corresponding to this call setting request and a channel on a line in the channel switching system assigned to the virtual channel.

Cell/packet assembly and disassembly apparatus and network system

An ATM exchange for performing the flow control adaptively in accordance with the seriousness of congestion, provided with a first threshold comparing circuit and a second threshold comparing circuit for comparing a cell queue length in a buffer of the exchange with a first and a second threshold, a timer counter which starts counting when the queue length exceeds the first threshold and is cleared to zero when the the queue length becomes smaller than the second threshold, a permissible time comparing circuit for comparing the count value with a permissible time, and a congestion counter for counting the output of the comparing circuit. The ATM exchange sets the first threshold, second threshold, and permissible time from the number of multiplexings of standard traffic, mean cell rate, peak cell rate, mean survival time of burst length, and false alarm probability, and judges that the heavy congestion is occurring when the queue length does not return to the second threshold or lower within the permissible time, and controls the flow of traffic, and at the same time, when this state continues, the flow restriction is enhanced depending on the elapsed time from the permissible time.

ATM exchange performing traffic flow control

A cell/packet assembly and disassembly apparatus is provided for efficiently connecting a line in a line switching system to an ATM network or a packet network, without causing congestion, to transmit and receive cells or packets therebetween. The cell/packet assembly and disassembly apparatus, upon detecting a call setting request outputted from a line switch board in response to a call originated from a terminal, starts cell assembly and cell disassembly of user information transmitted and received between a channel on a line in the line switching system corresponding to the call setting request and a virtual channel on the ATM network assigned to the channel. Also, when detecting a call setting request outputted from a predetermined virtual channel in the ATM network, the packet or cell assembly and disassembly apparatus starts cell assembly and cell disassembly of user information transmitted and received between the virtual channel on the ATM network corresponding to this call setting request and a channel on a line in the channel switching system assigned to the virtual channel. Further, when detecting the reception of a call disconnect request from the line switch board or from a predetermined virtual channel in the ATM network, the packet or cell assembly and disassembly apparatus stops the cell assembly and the cell disassembly of the user information transmitted and received between the corresponding virtual channel and the channel on the line in the line switching system.

Cell/ packet assembly and disassembly apparatus and network system

In a shaping method of controlling interval of transmission of cells to a transmission path, an input cell is temporarily accumulated in a buffer memory such that transmission time of the input cell is decided according to a traffic condition beforehand registered for each VPI and a traffic condition registered in advance for each VPI/VCI. The conditions are stored in a parameter table. The transmission time is compared with transmission time assigned to each of the preceding cells accumulated in the buffer memory. If conflict occurs therebetween, the transmission time is corrected and then correspondence between the transmission time and identifying information of the input cell are stored in an output control memory. Referring to the memory, the cells are read from the buffer memory in the sequence of transmission time to be sent to an output communication line.

ATM interface and shaping method

In a communication network including a plurality of nodes, when it is desired for a processor A of one of the nodes to reset another processor B within the same node or within another of the nodes, the processor A side generates a reset cell and transmits it to the party processor B side through a channel. The party processor B side confirms that the received cell is a reset cell, accepts the cell, and outputs a reset signal to the processor B to reset the processor B.

Growing community of inventors

Yokohama, Japan

Tatsuo Mochinaga