VoIP - Voice Over IP

Voice over Internet Protocol (VoIP ) is a protoco optimized for the transmission of voice through the Internet or other packet switched networks using VOIP Codecs and VoIP is often used to Define Real Time Voice Transmission instead of the protocol implementing it. VoIP is also known as IP Telephony , Internet telephony , Broadband telephony , Broadband Phone and Voice over Broadband .Regular house phones i.e Traditional Phones can make VOIP Calls using analog telephone adapter (ATA) provided by the VOIP company or purchased from a third party VOIP Hardware Vender.

Telecom or Networking Companies which provides VoIP service are commonly referred to as VOIP Providers, and protocols which are used to carry voice signals over the Internet(IP network ) are commonly referred to as Voice over IP or VoIP protocols. They are commercial realizations of the experimental Network of Network Voice Protocol (1973) invented for the ARPANET providers. Main Advantage of VOIP Over The Other Networks is due to utilization of single network to carry voice and data creating a Unified Communication Environment,Becouse users have existing underutilized network capacity that can carry VoIP for no additional cost for End Users. VoIP to VoIP phone calls are mostly free, while VoIP to public switched telephone networks, PSTN , in which the End User ( VOIP User) need have to pay the cost.

Voice over IP protocols carry telephony signals as encoded digital audio, typically reduced in data rate using VOIP data compression codecs in which data encapsulated in a data packet stream over IP.

There are two types VoIP calling : Direct outward Diling (DOD) and Direct Inward Dialing (DID) which need access numbers . DID will connect the caller directly to the VoIP user while access numbers require the caller to input the extension number of the VoIP user.