Differences between real and theoretical technical values of the voice over IP codecs

Abstract

The values of the voice codecs’ technical features play a very important role when the network administrator is dimensioning the bandwidth that a VoIP communications network with SIP is going to use. In the following research, we obtained the real values of the voice codecs as the payload, bit rate, PPS and frame size through Wireshark. For this, we performed VoIP real calls through softphone applications installed in smartphones with eight voice codecs. The results obtained for this case study demonstrate that there are differences between the theoretical and the real values, and that the real values are constant in the proposed case scenarios. We conclude that directly use the theoretical values would oversize the number of users that could communicate at the same time in a VoIP network