A Multi - level Explicit Rate Control Scheme for ABRTra c with Heterogeneous Service

The Available-Bit-Rate (ABR) service that is being standardized by the ATM Forum dynamically determines the maximum transmission rate, the explicit rate, of a connection. A drawback of the dynamic 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 diierent transmission rates bounds to connections. ABR traac is controlled at three levels. At the topmost level, bandwidth is dynamically regulated between CBR, VBR, and ABR traac sources. At the next level, bandwidth is controlled between diierent classes of ABR traac. At the lowest level, bandwidth is distributed among connections belonging to the same ABR traac class. The eeectiveness of the proposed scheme is demonstrated in simulation experiments.