Voice over IP (also called VoIP, IP Telephony, and Internet telephony) is technology enabling routing of voice conversations over the Internet or any other IP network.
The voice data flows over a general-purpose packet-switched network, instead of the traditional dedicated, circuit-switched voice transmission lines.
This arrangement has several advantages over traditional telephony:
- Freer innovation. Innovation progresses at market rates rather than the slow pace of the multilateral International Telecommunications Union (ITU) committee process, resulting in more new advanced features.
- Lower per-call costs. Once a network connection is in place, a phone call may have no additional charge.
- Lower infrastructure costs. VoIP reduces the traditional scheme—two separate wiring systems, one for voice and one for network—to a single connection.
- Stability. A higher degree of reliability and resilience may be possible as network reliability improves.
- "Future proof" hardware. Since functionality is software (protocol) based.
Protocols used to carry voice signals over the IP network are commonly referred to as Voice over IP or VoIP protocols.
Voice over IP traffic may be deployed on any IP network, including ones lacking an internet connection, for instance on a building-wide LAN without an internet connection.