Other

Pierre Boyer

Michel Servel

Yvon Rouaud

Didier Tranchier

The invention is a method of controlling asynchronous time-division communications. Cells received from an in-coming time division multiplex system are delivered to an out-going asynchronous time division multiplex system. Each in-coming cell is stored in a buffer memory at an address that corresponds to its re-sending time. At the time when the next cell of a particular communication arrives, the number of previously stored cells for that particular communication, that are stored in the buffer memory, is compared with a maximal number assigned to the particular communication. If the first number exceeds the second number, the next in-coming cell is not re-sent. Besides the buffer memory, the system includes a status memory and an arithmetic and logic unit. The status memory is divided into zones, each zone having two sections. When the next cell is received, a first number of cells stored in the first section of the particular communication which were stored in the buffer memory and which have not yet been sent, is compared with the maximal number stored in the second zone. The arithmetic and logic unit makes the comparison and inhibits the re-sending of the next in-coming cell, if the first number exceeds the maximal number.

Method and a system of control of asynchronous time communication outputs

The invention smooths asynchronous time communication outputs which are formed by cells received from an incoming synchronous time multiplex(XE) in order to supply an outgoing asynchronous time multiplex(XS). Each incoming cell is stored in a buffer memory (MT) with an address (Add) corresponding to the actual time when that cell will be transmitted (t) on the outgoing time multiplex (XS). The address (Add) of the cell entering the buffer memory (MT) is determined by calculating a function of the theoretical minimum time period (pm) between outgoing cells. The searching in the buffer memory (MT) is for the first free address (Add) corresponding to an actual transmission time (t) which is chronologically beyond the next theoretical transmission time (tso). The actual time for outgoing transmission is determined as a function of a period (pm) allotted to the communication to which the incoming cell belongs. The period (pm) corresponds to the theoretical minimum time period between transmitted cells in the outgoing synchronous time multiplex (XS).

Method and system of smoothing and control of asynchronous time

The invention provides a method of measuring the load of a communication system, and more particularly of a multiplex switching network for asynchronous cells or packets. Each cell transmitted on the multiplex has a registered value which is divided by a predetermined number (N). The value forms the first operand (E2) of a subtraction and the result of the division forms the second operand (E1). A predetermined value is added to the result of the subtraction when the heading of the transmitted cell contains a particular identifier. A zero value is added in the contrary case. The result of the subtraction followed by the addition constitutes the new value which is to be recorded, which likewise represents the measurement of the load. The identifier identifies, for example, an occupied cell or a cell belonging to a given virtual circuit. A circuit for implementing the method is likewise described.

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Lannion, France

Pierre Boyer