Traffic engineering for VoIP network based on PSTN statistical models

This paper shows an analysis how to calculate proper bandwidth for VoIP calls after proper dimensioning PSTN network. For this purpose, we use Erlang B and extended Erlang B formulas. Further, we have developed a software tool to calculate proper numbers of the circuits on the PSTN side (using our bandwidth calculator) and after that, bandwidth on the IP. By another word, traffic analysis will be conducted to VoIP networks considering impact of many factors on the bandwidth: voice codec, samples, VAD, RTP compression. The regression analysis is used to show trends of the subscriber behavior in the future (for specific category of subscribers). Finally, simulation results are compared with data obtained by bandwidth calculator.