VoIP (Voice over IP) The Future of Telecommunications
Voice over IP VoIP (voice over IP) is the transmission of voice and multimedia content over Internet Protocol (IP) networks. VoIP is now a realistic solution for businesses looking for an alternative to traditional telephone networks known as Public Switched Telephone Networks (PSTN). VoIP calls can be made phone-to-phone, computer-to-phone, or in other ways.
VoIP encapsulates audio via a codec into data packets, transmits them across an IP network and decapsulates them back into audio at the other end of the connection. VoIP endpoints include applications running on mobile devices and PCs or dedicated desktop VoIP phones. VoIP endpoints typically use codecs, such as G.711, this does transmit uncompressed packets, or G.729, which does compressed packets which reduce bandwidth requirements. VoIP typically supports non-voice communications via the ITU T.38 protocol for sending faxes over VoIP.
VoIP Session Initiation Protocol (SIP)
Once voice is encapsulated onto IP, it is typically transmitted via the real-time transport protocol or through its encrypted variant, secure real-time transport protocol. The Session Initiation Protocol (SIP) is most often used for signaling that is necessary to create, maintain and end calls. Within enterprise or private networks, quality of service is typically used to prioritize voice traffic over non-latency-sensitive applications to ensure acceptable voice quality.