Multilevel dynamic bandwidth allocation using buffer observation for cousin-fair access systems

This paper proposes two techniques for reducing the buffer size and computational complexity of an aggregation layer-2 switch (L2SW) in access systems by using buffer observation and multilevel dynamic bandwidth allocation (DBA). The conventional architecture for providing cousin fairness, which realizes fairness among multiple passive optical network (PON) branches, needs a huge buffer in an L2SW that depends on the number of optical network units (ONUs). Our proposal reduces the required buffer size for an L2SW that depends on the number of optical subscriber units (OSUs), which is much smaller than the number of ONUs. The proposed techniques reduce by more than two thirds the amount of unfairly distributed bandwidth caused by the lack of cousin fairness. A simulation result obtained with our proposed approach shows improved cousin fairness among multiple PON branches with a smaller buffer.