The resilient packet ring （RPR） is a new technology for high-speed backbone metropolitan area networks?A key performance objective of RPR is to simultaneously achieve high utilization

spatial reuse

and fairness?The core technical challenge for RPR is the design of a bandwidth allocation algorithm that dynamically achieves these three properties?In this paper

we introduce some problems in current fairness algorithm

and discuss a new dynamic bandwidth allocation algorithm called DVSR（Distributed Virtual-time Scheduling in Rings）.