Internet Protocol Telephony (IP Telephony)

Internet Protocol Telephony (IP Telephony) is the use of IP-based networks to build, provide and access voice, data or other forms of telephonic communications. IP telephony provides traditional telephonic communication over an IP-based network, the Internet - via an Internet service provider (ISP) - or directly from a telecommunications service provider.

IP telephony is designed to replace the telecommunications' infrastructure of circuit switched public data networks (CSPDN) and public switched telephone networks (PSTN) with packet switched IP communication networks.

In a consumer IP telephony solution, a soft IP phone application and backend Internet connection enable voice and data communication, such as calling and faxing. A user may call other softphone users, send or receive faxes and even communicate with circuit switched and cellular communication services.

In an enterprise environment, IP telephony is implemented through physical IP phones that work on top of an IP network infrastructure. An IP phone's built-in firmware provides the complete functionality for initiating and managing telephonic communications. Moreover, IP telephony also supports video communication between two or more users.

Voice over Internet Protocol (VoIP), a popular IP telephony implementation, only supports voice communication over IP.