This session addresses methods for scaling VOIP gateway and UM server deployments as well as pertinent UM performance metrics. Learn quantitative methods for determining the number of circuits, T1s, E1s, VOIP gateways and UM servers required to support a UM infrastructure. As well, gain exposure to the most relevant UM performance counters and suggested thresholds through a discussion of how UM performance is measured in MSIT, the world's largest UM deployment (90 dialplans, 63 individual sites).