Design and performance analysis of a dynamic protocol achieving user fairness in high-speed dual-bus networks

The IEEE 802-6 DQDB protocol solves the existing problems in prior round-robin high-speed MAC protocols. However, it introduces a new performance unfairness problem when the network size or channel bandwidth increases. The pi-persistent protocol, on the other hand, does not pass any control information over the channels, and was shown capable of achieving various fairness criteria, when each station knows the loads of all other stations. The authors propose a dynamic pi-persistent protocol that is capable of adjusting the network to fair operation in an environment where the station loads change over time. The protocol requires passing of some control information through the network. The information passed is not as detailed as the request information in DQDB. The authors analyze the performance of the protocol in a batch arriving model for load increase. The results show that the protocol is both fast and accurate in responding to network load changes