Message Delay Analysis for Polling and Token Multiple-Access Schemes for Local Communication Networks

Two efficient polling (token) schemes, which provide multiaccess coordination for local area networks, are described, analyzed, and compared. The two multiple-access polling protocols described here utilize gated and exhaustive disciplines in ordering the transmission of the messages buffered at each terminal. The delay-throughput performance behavior of polling schemes operating under the above mentioned disciplines is derived. Network terminals are modeled as independent sources, which generate messages in accordance with a renewal process. A queueing theoretic approach is employed in deriving the actual message delay. behavior of both schemes. Several comparisons are presented. Interesting results are obtained when we compare the average message waiting times in the case when the network traffic is completely balanced with the ease when this same traffic is mostly due to a single node. The latter case would arise, for example, m networks employing gateways.