Adaptive bandwidth balancing on DQDB networks

The bandwidth balancing (BWB) scheme has been used on distributed queue dual bus (DQDB) networks to improve the fairness of bandwidth allocation. Flexible dynamic bandwidth allocation can be achieved by using nonuniform BWB modular values. However, the local load condition in each station is ignored. The authors change the BWB scheme to be adaptive based on the local traffic intensity in each station. No additional hardware is required except a simple queue length monitor. The fairness of access delay time for heavily loaded networks is improved, while the original static BWB scheme remains more effective for lower load levels. The transient time for reaching throughput steady state is reduced at the cost of some overshooting. Variations of adaptive BWB schemes are discussed and analyzed numerically