Controlling QoS with delays and cell drops

We suggest the use of maximum allowable delays through a switch as a tool for the control of quality of service (QoS) for classes of real-time traffic in ATM. Our proposed admission control (AC) procedure may accept an incoming cell, or decide to drop it at the input to avoid needless congestion when it appears that the cell´s delay constraints will not be respected, or when the AC considers that the cell may cause excessive delay for other cells. Simulations show that early cell drop based algorithms provide better overall performance and that they are robust to variations in traffic characteristics