Voice over Internet Protocol (voip
)
IP Telephony, also called 'Internet telephony', is the technology that makes it possible to have a telephone conversation over the Internet or a dedicated Internet Protocol (IP) network instead of dedicated voice transmission lines. This allows the elimination of circuit switching and the associated waste of bandwidth. Instead, packet switching is used, where IP packets with voice data are sent over the network only when data needs to be sent, i.e. when a caller is talking.
Voice over IP traffic does not necessarily have to travel over the global Internet; it may also be deployed on private IP networks for example on a LAN inside a single building. The protocols used to carry the signal over the IP network are commonly referred to as Voice over IP or VoIP protocols.
The development of mass-market VoIP services over broadband Internet access services, in which subscribers make and receive calls as they would over the PSTN, is currently booming as more and more people realize they can talk for hours without incurring gargantuan telephone bills. This requires an analog telephone adapter (ATA) to connect a telephone to the broadband internet connection.
A great number of telecommunications companies worldwide are investigating the viability of IP Multimedia Subsystem (IMS) that will bring together Internet technologies with the mobile world, using a pure VoIP infrastructure. It will enable them to upgrade their existing systems while embracing Internet technologies such as the Web, email, instant messaging, presence, and video conferencing. It will also allow existing VoIP systems to interface with the conventional PSTN and mobile phones.