International Business Machines Corporation

Jean M Munier

Victor Spagnol

Andre Pauporte

Jean L Calvignac

Michel Poret

Gerald Lebizay

Michel Bouillot

Pierre Austruy

Georges Gallet

A data transmission network congestion control mechanism requires knowledge of the sequence of occurrence of two dates d1 and d2, respectively defined by times t1 and t2 provided by a wraparound timer as respective numbers A and B coded in a 2's-complement form. Relative date discrimination is implemented by dividing the wraparound timer period into four consecutive intervals, each defined by the two most significant bits of the timer count. The value of the most significant bits and the sign of A-B, are used to derive a one-bit 'X' indicator, the binary value of which indicates which of the two dates d1 and d2 was first to occur.

Method and system for implementing relative time discriminations in a

The present invention relates to an efficient point-to-point and multi-points routing system and method for programmable data communication adapters in packet switching nodes of high speed networks. The general principles of this efficiency are the following:

Efficient point-to-point and multi-point routing mechanism for

A Control Unit is described, including a Processing Unit (12) controlled by a Service Processor (14), and a plurality of adapters (18) exchanging data and/or control signals with said Processing Unit (PU). For ensuring a continuous operation of the Control Unit, the adapters are partitioned into at least two sets (56,58), and the PU is partitioned into at least two parts (26,28), each set of adapters being connected to a dedicated PU part by a primary bus (52,54). Besides, in order to allow the fallback of a set of adapters onto another PU part if the PU part to which it is normally connected is inoperative, a bus switching device (30) is provided. This bus switching device includes at least two Switch parts (38,40), and each Switch part performs the switching of a given set of adapters onto a given PU part, according to the status of each PU part. Therefore, each Switch part is connected to a given set of adapters by a primary bus (52,54), and to the other sets of adapters by secondary busses (46,48) which become active in fallback mode.

Adapter-bus switch for improving the availability of a control unit

Method for transporting asynchronous data and synchronous non coded information NCI bits on a common channel operating at (n+1)/T bits per second, in slot of duration T containing n+1 bits, the data and NCI portions of the bit stream to be transported being delimited by a flag having a specific pattern which cannot be simulated by the data bits. During the periods where there is an NCI activity, the first n bits of the slot are used for transporting NCI bits and the last bit is used for transporting an additional data bit, if the said first n bits are different from the flag pattern and said last bit is set to a first binary value (0) if said first n bits are similar to the flag pattern. During the periods where there is no NCI activity, data bits are sent in at least one slot delimited by two slots, the first n bits of which are set to the flag pattern and the last bit of which is set to the second binary value (1). A transmitting device and a corresponding receiving device are implemented for generating the bit stream built using the subject method on a communication channel and receiving the so-built bit stream.

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Cagnes sur Mer, France

Jean M Munier