VoIP - Voice Over Internet Protocol

Voice Over Internet Protocol (VoIP) The most immediate benefit of VoIP for most businesses is savings on long distance charges. Companies equipped for VoIP can place long-distance calls over the Internet rather than the PSTN (Public Switch Telephone Network) and avoid paying long distance charges. Since most companies already pay for broadband Internet connections, the only additional requirement is the equipment that connects telephones to the IP network. the deployment of Voice Over Internet Protocol (VoIP) VoIP is needed to unify Voice and Data into single network and to cut the costs. I believe this is the way will shape the future. Before: Voice + Data Now: Only Data It is true since IP packet can carry Voice, at both end of IP, there is mechanism to convert IP to voice that we can hear these spectrium was predefined on the handshaking of what scheme will be used such as G.711 A-law and mu-law (G.711 is an ITU-T standard for audio companding. It is primarily used in telephony. The standard was released for usage in 1972. G.711 is a standard to represent 8 bit compressed pulse code modulation (PCM) samples for signals of voice frequencies, sampled at the rate of 8000 samples/second. G.711 encoder will create a 64 kbit/s bitstream. There are two main algorithms defined in the standard, mu-law algorithm (used in North America & Japan) and a-law algorithm (used in Europe and the rest of the world). Both are logarithmic, but the later a-law was specifically designed to be simpler for a computer to process. The standard also defines a sequence of repeating code values which defines the power level of 0 dB.) After the connection between both parties (calling and called) RTP (Realtime Transport Protocol) is taken over after the handshaking. SIP (Section Initial Protocol) is used in the following diagram. References: http://www.voip-forum.com/