Stability Analysis of Intelligent Marking EPRCA for ABR Congestion

The EPRCA (Enhanced Proportional Rate Control Algorithm) is a leading congestion control protocol for Available Bit Rate (ABR) service in ATM networks. Even though the EPRCA has been adopted by the ATM forum as the standard for ABR congestion control, we show that this protocol is only marginally stable. The stability analysis presented in this paper does not consider interactions among network components and should be considered as a bottleneck stability result. We show that, if a queue is the bottleneck of a congested path, then its queue size will eventually decrease. However, if a queue is not congested, its queue size can actually increase and a congestion can be self-induced.