Interconnection of token ring LANs using bridges: an approximate mean waiting time analysis

The interconnection of token-ring local area networks (LANs) via store-and-forward bridges is considered. The mean-packet-delay performance of a system of token rings connected in series is analyzed by approximating the interarrival times at the bridges by renewal processes. The approximation gives simple formulas for the mean waiting times and agrees reasonably well with simulation results in most of the cases considered. Also, the conditions under which the performance of a single token-ring LAN can be improved by partitioning it into bridged subrings are investigated. It is found that splitting can improve performance as long as the fraction of the internetwork traffic is below a threshold which depends on the total input traffic