Alcatel Cit

Denis Le Bihan

Georges Thiebaut

A device for regulating the throughput of virtual circuits carried by an asynchronous time-division multiplex transmission channel in which the incoming cells of an input asynchronous time-division multiplex channel (mtr) including a header containing a destination indicator which can be used as a virtual circuit identifier are routed to a cell memory (MT) comprising a . . . , MAn), each cell being stored in the virtual circuit buffer memory associated with the virtual circuit to which the cell belongs, and the outgoing cells of an output asynchronous time-division multiplex channel (mte) are read in the same virtual circuit buffer memories (MA1, MA2, . . . , MAn). Cells to be transmitted on the outgoing link are read from the buffer memories in an order such that the cells from the same virtual circuit buffer memory are spaced on average by at least an interval specifier to that virtual circuit.

Device for regulating the throughput of virtual circuits on an

A memory location is assigned to each virtual circuit, this location containing a context (CT) that defines the evaluation conditions for measuring the throughput of the virtual circuit and then, upon reception of each cell, providing for the context relating to the virtual circuit to which the cell belongs to be read. A clock signal is adapted to supply a current time associated with this virtual circuit. An indication of the measuring interval start time is written into the context (CT) for a virtual circuit upon arrival of a first cell for this virtual circuit. Upon the arrival of a subsequent cell for this virtual circuit, the context is read and from the current time (hc) the time interval start time is subtracted. The time difference is compared to a specified measurement interval duration and the number of cells already received is incremented. This number of cells already received is used as a measurement of the mean throughput of the virtual circuit when the time difference is equal to or greater than the duration of the measurement interval. The context is then re-initialized.

Method and device for evaluating the throughput of virtual circuits

A memory location is assigned to each virtual circuit, this location containing a context (CT) that defines the evaluation conditions for measuring the throughput of the virtual circuit and then, upon reception of each cell, providing for the context relating to the virtual circuit to which the cell belongs to be read. A clock signal is adapted to supply a current time associated with this virtual circuit, and throughput measurement circuits supply, at the arrival of a cell, a virtual circuit throughput measurement for this virtual circuit. The context (CT) includes at least one throughput threshold, and provision is made to compare such a throughput measurement therewith in order to drive an excess rate counter in a first direction if this threshold is reached or exceeded or in another direction if the threshold is not reached, it being determined if such driving has brought the excess throughput counter to an end position in the first direction in order to then supply a signal (OSC) indicating the need for corrective action.

The incoming cells of a input asynchronous time-division multiplex channel (mtr) are counted by a counter (FFB) assigned to each virtual circuit which is incremented on each incoming cell of the virtual circuit and decremented periodically. Clock signals define consecutively numbered cell times (ntc). Queue and chaining table (FAVE, FCVN) define a cell time queue (FAF, FAL, FAV) specific to each of the cell times, a virtual circuit being assignable to a cell time by writing its identifier into the corresponding cell time queue. A controller (MC) uses the content of the cell time queues (FAF, FAL, FAV) and, for each cell time, identifies a virtual circuit to be processed and decrements the counter (FFB) belonging to this virtual circuit. The controller further includes arrangements whereby any virtual circuit whose counter is not idle is assigned to one of the cell times to be decremented by virtue of the arrival of this cell time.

Device for evaluating the throughput of virtual circuits on an

A memory (MCT) is used in which a location is assigned to each virtual circuit, this location containing a context (CT) that defines the evaluation conditions of the throughput of the virtual circuit and, upon reception of each cell, providing for the context relating to the virtual circuit to which the cell belongs to be read, for the purpose of evaluating the throughput of the virtual circuit. A clock signal (BC) is used to supply a current time associated with this virtual circuit. An indication of the start time is written into the context (CT) for a virtual circuit and, upon arrival of a cell for this virtual circuit, the context is read and from the current time supplied by the clock signal, the start time supplied by the read context is subtracted and the thus established time difference is used as a measurement of instantaneous throughput of the virtual circuit, defined as the time interval that has elapsed between two cells, this measurement of instantaneous throughput being supplied to an evaluation circuit (BT), while the current time is written into the context as the start time.

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Lanmerin, France

Denis Le Bihan