International Business Machines Corporation

Andre G Tracol

Jean L Calvignac

Daniel Orsatti

Gerard Barucchi

Gilles Toubol

Claude J Gergaud

Jose Galcera

Etienne Grimanelli

The system performs an optimized number of simultaneous transfers of data packets between pairs of units comprising an origin unit and a target unit selected among N data processing units (8). Each data processing unit comprises a set of outbound queues with one outbound queue associated with each one of the data processing units to which it may send data packets, for storing the data packets to be sent by the data processing unit to the data processing unit associated with said one outbound queue. The transfers are performed during a time burst Ti+1 by data switch 6 under control of switching control signals sent to data switch by the units on lines 16-1 to 16-N in response to control out signals generated by scheduler 4 during previous burst time Ti. The scheduler runs a selection algorithm which gives each unit an equal probability to be selected as origin unit in a given period.

Switching system for simultaneously transferring data between data

The synchronization circuit resynchronizes the data bits received from remote devices on line or link (20-1) with their own clock CS and frame synchronization signal FS with a central clock CO and central frame synchronization signal FO. The received bits are sequentially arranged in an n-bit cyclic buffer (114-1) with the received bit clock CS. The arranged bits are sequentially picked at the opposite buffer position with the central clock CO. The buffer loading position is provided by binary counter 102 incremented by CS and the buffer picking portion is given by binary counter 100 incremented by CO. At initialization counters 102 and 100 are set to 0 and n/2. The resynchronized data bits on line 21-1 and the resynchronized frame signal FSR on line 61-10 are provided to an additional circuit which synchronize the data bits at the frame level.

Synchronization circuit for a synchronous switching system

Described is a decentralized data transmission system and a method of operating the system. A relatively high speed transmission medium connects a number of relatively lower speed terminals in a loop or similar configuration. A central or monitoring station is connected in the transmission medium which includes a memory table containing the listing of the station addresses connected to the transmission loop. The monitoring station operates as a control station for transmitting the address of a first station to be enabled to transmit a message. The addressed station recognizes its address and responds either with a message destined for another station or with a signal that no message is to be sent. At the end of a message, an enabled station sends a special character to notify the monitoring station that the next station in the memory table can be addressed to grant usage of the transmission medium.

Decentralized data transmission system

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Cagnes sur Mer, France

Andre G Tracol