Analysis of ATM cell loss for systems with on/off traffic sources

Cell loss, which occurs when buffers overflow in ATM switches, is a key measure for the performance of an ATM network. An ATM network must be designed for very low and predictable cell loss probabilities to provide adequate quality of service for all users. Many methods have been proposed for allocating bandwidth and determining buffer size requirements to provide quality-of-service guarantees. The probabilistic nature of these methods is subject to overly optimistic allocations (insufficient in the worst case) or overly pessimistic allocations (over specified in the best case). The authors present an exact analysis of cell loss for periodic on/off (bursty) traffic sources. Periodic on/off traffic sources are representative of output traffic from leaky-bucket rate-control mechanisms as used in ATM networks. Closed-form equations for buffer sizing and cell loss probabilities are developed and rigorously proved for a single queue with multiple traffic sources and multiple queues with multiple traffic sources serviced via a round-robin discipline. These closed-form equations can be used in concert with probabilistic methods to ensure that buffer and bandwidth allocations are made between the best- and worst-case requirements