Rate allocation policy with MCR/PCR support and distributed ABR implementation using explicit rate feedback

An important concept in the available bit rate (ABR) service model as defined by the ATM Forum is the minimum cell rate (MCR) guarantee as well as the peak cell rate (PCR) constraint for each ABR virtual connection (VC). Because of the MCR and PCR requirements, the well-known max-min fairness policy no longer suffices to determine rate allocation in the ABR service model. We introduce a network bandwidth assignment policy, MCRadd, which supports both the MCR and PCR requirements for each ABR virtual connection. A centralized algorithm is presented to compute network-wide bandwidth allocation to achieve this policy. Furthermore, an explicit-rate (ER) based ABR switch algorithm is developed to achieve the MCRadd policy in the distributed ABR environment and its convergence proof is also given. The performance of our ABR algorithm is demonstrated by simulation results based on the benchmark network configurations suggested by the ATM Forum.