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.