Modeling and simulation applied to capacity planning of voice gateways: a case study

In this work, we applied modeling and simulation to plan and evaluate the capacity of a real enterprise voice gateway system. We modeled the analyzed voice gateway and assessed it under different workload scenarios. We evaluated the actual setup under the real current workload demand, as well as future expected demands in terms of voice long-distance calls using PSTN and VoIP providers. Also, the existing voice gateway capacity was tested facing calls to mobile phones through GSM Sim cards. Finally, we tested a proposal setup to reduce the number of simultaneous E1 channels used per voice call, and found that our approach reduced the E1 usage rate by 14%.