Scaling of buffer and capacity requirements of voice traffic in packet networks

The migration of voice communication from the Public Switched Telephone Network to the Internet pushes the need to adequately size network resources such as buffers and capacity. This paper addresses the problem of how these resources should be scaled in the number of voice flows N in order to guarantee predefined packet loss probabilities and end-to-end delays. By deriving non-asymptotic buffer overflow probabilities at both edge and interior network nodes, the paper demonstrates that O(1) buffers are sufficient to ensure probabilistic packet loss constraints at all utilizations. Also, by deriving end-to-end delay bounds, the paper shows that the required per-flow capacities are bounded by O (1/N) when probabilistic end-to-end delay guarantees are sought. Numerical examples illustrate that statistical multiplexing dominates the effect of scheduling in multi-nodes scenarios with high capacities.