ATMR (Asynchronous Transfer Mode Ring) is a media access control (MAC) protocol for local and metropolitan area networks (LANs and MANs) working in the Gbit/s range. The ATMR network architecture is based on a combination of a slotted ring network, spatial slot reuse and a distributed cycle reset mechanism. The performance evaluation is based on simulation results which have been obtained in homogeneous and heterogeneous traffic scenarios. Particularly user throughputs are compared with those of a pure slotted ring network. We demonstrate that the fairness mechanism employed in the ATMR MAC protocol regulates the access to the medium in a global and fair manner. Furthermore we illustrate the throughput advantage obtained by the introduction of a special bandwidth allocation scheme.