ABR service in ATM networks: performance comparison between adaptive stochastic and ERICA flow control schemes with guaranteed minimum cell rate

Two explicit rate-based flow control schemes for congestion avoidance in ATM networks: explicit rate indication for congestion avoidance (ERICA) and a proposed adaptive stochastic (AS), are compared under heavy load conditions. Neither of the schemes dictates a particular switch architecture. The requirements tested include: utilization, queuing delay, delay variance and queue size. A simple network topology involves an ATM switching node which is modeled as a single server queuing system fed by a number of highly bursty traffic sources. Neither packet discarding, nor packet retransmission mechanisms are included. The controllable sources' allowed cell rates (ACR) have been dynamically shaped by the explicit feedback messages from the switch. The results of a simulation study are presented which suggest that the AS scheme can provide for higher priority traffic considerably shorter queuing delay, delay variance and average queue size, particularly on shorter links, with slightly lower utilization.