Performance of Unidirectional Broadcast Local Area Networks: Expressnet and Fasnet

Local area communication networks based on packet broadcasting techniques provide simple architectures and flexible and efficient operation. Unidirectional broadcast systems use a unidirectional transmission medium which, due to their physical ordering on the medium, users can access according to some efficient distributed conflict-free round-robin algorithm. Two systems of this type have been presented in the literature: Expressnet and Fasnet. In this paper we briefly describe these two. We identify three different service disciplines achievable by these systems and discuss and compare the performance of each. These systems overcome some of the performance limitations of existing random-access schemes, making them particularly well suited to the high bandwidth requirements Of an integrated services digital local network.