call admission control (CAC)

Call Admission Control(CAC) is a method for improving voice quality during the transmission of voice and other real-time applications in IP networks. CAC technology is intended to safeguard the voice quality of Internet telephony( VoIP).

Call Admission Control prevents overloading of the available bandwidth and the associated impairment of speech intelligibility.

In the CAC process, IP-based voice transmissions are protected against congestion. To prevent voice quality from deteriorating, no further voice connections are established above a certain load. If the permissible number of voice connections is exceeded, the existing voice connections must absorb the additional voice traffic, which leads to packet losses and impairs the voice quality of all other voice connections.