A multi-level explicit rate control scheme for ABR traffic with heterogeneous service requirements

The Available-Bit-Rate (ABR) service that is being standardized by the ATM Forum dynamically determines the maximum transmission rate, so-called explicit rate, of a connection. A drawback of the ABR control scheme for calculating the explicit rates is that it tries to allocate the same bandwidth to all ABR connections regardless of the application type of the connection. In this study a multi-level explicit rate scheme is proposed that can allocate different explicit rates for different classes of connections. ABR traffic is controlled at three levels. At the topmost level, bandwidth is dynamically regulated between CBR, VER, and ABR traffic sources. At the next level, bandwidth is controlled between different classes of ABR traffic. At the lowest level bandwidth is distributed among connections belonging to the same ABR traffic class. The effectiveness of the proposed scheme is demonstrated in simulation experiments