Abstract: The packet flow of each virtual circuit is measured and compared to an allocated average value. At each transmission authorization request (DAE'), when found to be less than the average value, a positive difference brings about an authorization to transmit and is translated into a right to transmit which is proportional to the time span since the previous request, the right to transmit being accumulated. When it is found to be greater than the average value, a negative difference brings about, if the number of accumulated transmission rights is positive, on one hand, the authorization to transmit and, on the other hand, a decrementing of the accumulated number, and if the accumulated number is nil, a refusal of authorization to transmit.Some examples of systems carrying out the process are described.The process and systems are applicable in particular to packets carried by asynchronous time multiplexers.