Fujitsu Corporation

Masashi Hirome

Tsuyoshi Matsumoto

Toshiyuki Yoshida

Hidetoshi Amari

Kenji Taniguchi

Takaharu Kajiwara

Kiyotaka Shikata

Hiroaki Nagao

Yushi Murata

Noriyuki Kimura

Takashi Tai

Naoki Sase

Keiichi Furukawa

Takeo Kubo

The present invention relates to a frame communication system composed of a code converter and a frame generator/decomposer. In order to improve a line efficiency without encapsulating transmitting data, a code converter in a frame transmitting device converts at least different specific codes X and Y within the transmitting data respectively into codes (Y, A) and (Y, B) composed of the code Y and at least specific codes A and B different from each other, and a frame generator prepares a frame of the transmitting data with the code X as a frame boundary. A frame decomposer in a frame receiving device recognizes a specific code X as a frame boundary to decompose receiving data, and a code converter converts codes (Y, A) and (Y, B) within the receiving data composed of a specific code Y, and specific codes A and B into codes X and Y.

Frame communication system

A ring transmission system includes nodes connected in a ring shape by transmission lines to communicate with each other. Each node includes a cell extracting unit which receives a cell from the transmission lines and separates a control field from the cell in accordance with a communication control procedure, the control field including a number of bits containing management data and a destination, the management data indicating information related to maintenance and operation of the ring transmission system. A separating unit separates, from the control field, one of management data for the node and management data for another node by comparing the destination with an identification of the node. A management data processing unit generates processed management data from the management data when the destination indicates the node. An intermediate unit generates a new cell containing the management data from the separating unit when the destination indicates the another node. The management data of the new cell is distinctly different from the processed management data. The intermediate unit transmits the new cell to the transmission lines.

Ring transmission system for providing efficient transmission of

There is provided a communication control method for a network including duplexed ring transmission lines and a plurality of communication controlling devices each accommodating a plurality of terminals and adapted to transmit data sent from any of the terminals and receive data over the ring transmission lines, the communication control method comprising the steps of: causing one communication controlling device to transmit monitoring cells simultaneously over the duplexed transmission lines, the monitoring cells each including a pass indication area for retaining a source address and identification information for identifying a passed communication controlling device; and causing another communication controlling device which receives the monitoring cells respectively from the duplexed transmission lines to relay and circulate the monitoring cells respectively over the duplexed transmission lines after writing in the pass indication area of each of the received monitoring cells data indicative of passage of said each monitoring cell. The communication control method improves the efficiency of the fault monitoring and fault reporting on the transmission lines of the ring LAN.

Control method of asynchronous data communications

In a ring transmission path, a synchronous multiplexing technique using pointer control is employed. To stabilize pointer values, at least one node is set as a master node. At the master node, the amount of delay by which to delay transmit data is made variable in order to place the transmit data in a fixed position in a transmitted frame regardless of its position in a received frame. At other nodes, the position of the transmit data in the transmitted frame is made variable in order to delay the transmit data by a fixed amount of delay. When the master node is bypassed because of a failure of the master node, etc., the adjacent node downstream detects that state and switches, automatically, to a master node.

System for controlling delays in a ring by assembling subframes with a

A multi-ring data transmission system which uses a plurality of transmission lines and provides a first circuit to add a sequential number of each of data packets and transmit the data packets to each of the transmission lines. A second circuit error check whether each of the data packets received via each of the transmission lines is normal or erroneous. A third circuit successively employs the data packets which are determined as being normal in the second circuit and are received via one of the transmission lines as received data packets in a sequence of the sequential numbers.

Multiring data transmission system

Transmitting data processing system

Growing community of inventors

Kawasaki, Japan

Masashi Hirome