Internet telephony is the integration and convergence of voice and data networks, services, and applications. Rapidly developing technology to convert analog voice input into digital data, sent through the network channels are available, and then converted back to sound output. Traditional circuit-switching networks such as telephone lines can be used in conjunction with packet-switching networks like the Internet, so the merging of communication modes such as email, voice mail, fax, pager, real-time human voice, and multimedia video conferencing into one integrated system. Transforming the Internet from a network application using phone lines to a common communications infrastructure through which voice is just one of a kind of data that are offered have a wide impact on applications, architecture, networks, economics, public policy, industry structure, regulation, and service providers.