Solving bandwidth and priority domination problems of DQDB metropolitan area networks

The bandwidth domination problem (BDP) in the distributed queue dual bus (DQDB) medium access control (MAC) protocol could occur if the network bandwidth is dominated by a single node when it is active early and other nodes having heavy traffic demands are active later. The priority domination problem (PDP) is the problem that the network bandwidth may be dominated by an upstream node with lower priority when it is active early and other nodes with higher priorities are active later. To solve the BDP a mechanism is provided such that the bandwidth can be shared among all active nodes. To solve the PDP a mechanism is provided such that nodes with higher priority can capture all the bandwidth. The authors propose two adaptive algorithms to solve the BDP and a priority mechanism to solve the PDP. The adaptive algorithms and priority mechanism were evaluated by simulation. It is also shown that if the adaptive algorithms and priority mechanism are combined together, then the nodes with highest priority can use all the bandwidth and the bandwidth can be balanced among these nodes rapidly