Voice over IP ("VoIP" for short), is a technology for making phone calls over IP circuits ("Internet Protocol" for its acronym in English) broadband. The move to VOIP calls via data networks use private IP management and for carrying calls from one place to another.
VOIP networks are known as "packet switched networks", because the calls are transmitted over the VoIP network in packets.
VOIP is highly efficient because the network is used only when data packets are transported.
VOIP vs. Traditional phone service.
With traditional phone service, a permanent connection for the call is established. Or trunk line carrying the call are kept in use all the time, eating facilities as the voice stream is delivered.
With VoIP, the voice stream is divided into packets, compressed and sent to the final destination via different routes, depending on the most efficient route given the availability of network congestion, etc ...
VOIP package delivery
When the call is made on a VOIP network, the first packet contains information about the call and subsequent packets containing the body of the call itself. At the receiving end, packets are reassembled, decompressed and converted into voice stream through various hardware and software elements, depending on the nature of the call and the final destination.
With VOIP calls can be realizer from a PC (softphone), an IP phone, an ATA (analog telephone adapter), or any other VOIP device, and may end up on a PC (softphone) In another IP telephone, a traditional telephone PSTN (Public Switched Telephone Network) or another VOIP device.