Calculation of Loss Probability in a Finite Size Partitioned Buffer for Quantitative Assured Service

This paper proposes an approximate yet accurate approach to calculate the loss probabilities in a finite size partitioned buffer system, for the achievement of a quantitative assured service in differentiated services networks. The input is modeled as a fractional Brownian motion (FBM) process including $J$ classes of traffic with different packet loss requirements. A first-in first-out (FIFO) buffer partitioned with $J-1$ thresholds is used to provide $J$ loss priorities. Heuristic expressions of the loss probabilities for all the $J$ classes are derived and validated by computer simulations. The proposed loss calculation technique is then extended to a general input process by using the recently proposed traffic substitution technique, where both long-range dependent (LRD) and short-range dependent (SRD) input sources are equivalent to a properly parameterized FBM. We also apply the loss calculation to admission control, where the partition thresholds are optimally configured for quality of service guarantee and maximal resource utilization. Computer simulation results demonstrate that resource allocation based on the accurate finite buffer loss analysis results in much more efficient resource utilization than that based on the classic large-buffer overflow approximation.