High performance fair bandwidth allocation algorithm for resilient packet ring

IEEE is currently standardizing a new high-speed backbone technology for MANs - the Resilient Packet Ring (RPR). A key performance objective of RPR is to achieve high utilization, spatial reuse, and fairness simultaneously. However, the algorithms proposed in current draft standards have some critical limitations. As shown in an unbalanced traffic scenario, the draft RPR algorithm will suffer from dramatic bandwidth oscillations within nearly the entire range of the link capacity. In this paper, we propose a new dynamic bandwidth allocation algorithm called Distributed Bandwidth Reallocated in Rings (DBRR), which is based on approximately virtual-time. It shows that with fairness information propagated along the ring, each node can remotely approximate the ideal fair rate for its own traffic at each downstream link, and the whole ring can obtain maximum spatial reuse and nearly lossless throughput.