Voice over Internet Protocol (also called VoIP,
IP Telephony, Internet telephony, and Digital Phone) is the routing
of voice conversations over the Internet or any other IP-based
network. The voice data flows over a general-purpose
packet-switched network, instead of traditional dedicated,
circuit-switched voice transmission lines.
Protocols used to carry voice signals over the IP network are
commonly referred to as Voice over IP or VoIP protocols. They may
be viewed as commercial realizations of the experimental Network
Voice Protocol (1973) invented for the ARPANET.
Voice over IP traffic might be deployed on any IP network,
including ones lacking a connection to the rest of the Internet,
for instance on a private building-wide LAN.
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