An efficient traffic control scheme for integrated voice, video and data over ATM networks: explicit allowed rate algorithm (EARA)

ATM networks are networks with guaranteed quality of service. The main cause of congestion in ATM networks is over utilization of the physical bandwidth. Unlike constant bit rate traffic, the bandwidth reserved by variable bit rate (VBR) traffic is not fully utilized at all instances. Hence, this unused bandwidth is allocated to available bit rate traffic (ABR). As the bandwidth used by VBR traffic changes, the available bandwidth for ABR traffic varies, i.e., the available bandwidth for ABR traffic is inversely proportional to the bandwidth used by the VBR traffic. Based on this fact, a rate based congestion control algorithm, explicit allowed rate algorithm (EARA), is presented. The EARA is compared with the proportional rate control algorithm (PRCA) and explicit rate indication congestion avoidance algorithm (ERICA), under congestion and fairness configurations. The results show that, with a minimal overhead on the switch, the EARA significantly decreases the required buffer space and improves the network throughput.