A proof for lack of starvation in DQDB with and without slot reuse

The DQDB is the IEEE 802.6 MAC standard protocol for metropolitan area networks (MANs). It is designed for the slotted, dual bus configuration. A simple way to improve the performance of the DQDB is to perform slot reuse and many methods have been suggested in the past to efficiently incorporate slot reuse with the DQDB. However, some of them can lead to starvation. We improve one of these previous suggestions and the main contribution of the paper is that for the first time we also provide a proof that the improved scheme ensures a lack of starvation. We also specify this proof for the important case of the DQDB without slot reuse.