A new analytic approach for the performance evaluation of buffer insertion rings is proposed which overcomes the basic limitations of former analyses. Key to our analysis is that the global performance model of a buffer insertion ring is decomposed into submodels in such a way that the basic interdependence of interarrival and transmission times of the frames transmitted is taken into account. The analysis itself is relatively straightforward and yields simple and explicit results for the mean delays of the frames. For special traffic patterns, the analysis is exact; for the general case, it is approximate but its accuracy turns out to be high, as comparison with simulation results shows. Copyright © 1983, by The Institute of Electrical and Electronics Engineers. Inc.