Improved fairness algorithm to prevent tail node induced oscillations in RPR

The IEEE P802.17 workgroup has standardized a ring network architecture and associated protocol called resilient packet ring (RPR). RPR tries to overcome previous MAN technologies shortcomings in high-speed networks. The RPR fairness mechanism suffers from severe permanent oscillations under certain conditions. Several propositions were made to solve this problem but all needed significant modifications of the current RPR protocol. In this paper, we propose an improved algorithm to prevent tail node induced oscillations. It requires only simple modifications to the current fair rate advertisement mechanism of RPR. Our simulation results show that the improvements work under various conditions and increase the average throughput of RPR.