Abstract: A new technique is developed to analyze the cell loss behavior of individual connections in finite intervals for ATM networks. The technique is applied to partial buffer sharing (PBS) in deriving formulae for calculating cell loss rate and queue length distributions for each cell class in a single connection in finite intervals. To maximize network utilization, a new and more flexible cell loss control mechanism called threshold-based loss balancing (TLB) is proposed which restricts the violation probability of each cell class. Comparisons of TLB and PBS on selected operating conditions reveal that TLB can accept more connections under the same workload conditions. PBS is shown to be a special case of TLB.