The invention relates to a buffer management method for sharing the storage capacity F of a buffer between its users, such as queues, communication links or equivalent, which store packets in the buffer, in which method the total number of packets stored in the buffer is calculated and, based on this, the buffer capacity to be granted to the users is controlled. According to the invention, a modified total number of packets T* stored in the buffer is determined from equation (1), where N=total number of users; a(i)=minimum buffer capacity (a(i>0)) allocated for user i; and c(i)=actual buffer capacity occupied by user i at the reference instant. Further, the storage of additional packets by user i is inhibited if the total T*>F and c(i)>a(i). ##EQU1##

In computers (Processor Unit 1, . . . , Processor Unit N) that handle the operation of an ATM switch, applications may communicate with each other by transmitting internal traffic cells to each other, which are transported among other subscriber traffic. By assigning service categories to the applications, which correspond as well as possible to their quality needs, it is possible to optimize the quality of the connection services of internal connections. By setting the traffic parameters of internal traffic individually changeable, internal traffic and subscriber traffic can be integrated in the best possible way. In the preferred embodiment, the service category can be selected connection-specifically. In such a case, each application selects the best possible service category. In the second embodiment, the connection-specific category is selected to be the same for all the applications. In such a case, all the applications use the same predetermined service category. It is possible to divide the application into groups and to select the same service category for all the applications. In such a case, the application within the group always use the same predetermined service category.