Reliability is a critical element of any VoIP network. It is fundamental to network performance and to subscriber retention and their experience. What’s more, it seems that network quality is becoming an increasingly important factor in attracting new customers.

Since it is a characteristic that can easily be measured, the impact of unreliable systems on operational performance can easily be determined. But this is a retrospective viewpoint: it depends on data collected through time.

Operators need to be sure that systems they select will provide the performance levels they need and cope with additional capacity as network traffic increases. If they offer Service Level Agreements (SLAs) to important customers, then they need to know that they can deliver on these terms.