VPN network that is constructed by using public wires to connect nodes. These systems use encryption and other security mechanisms to ensure that only authorized users can access the network and that the data cannot be intercepted.
Security in VoIP Networks Juan C Pelaez Florida Atlantic University
Overview of VoIP(1) VoIP enables people to use the Internet as the transmission medium for telephone calls. For users who have free, or fixed-price, Internet access, Internet telephony software essentially provides free telephone calls anywhere in the world. To date, however, Internet telephony does not offer the same quality (easy target of security attacks) of telephone service as direct telephone connections.