How VOIP Works

VOIP ("Voice Over Internet Protocol") is a technology that sends phone calls over broadband IP (Internet Protocol) circuits. VOIP calls move over privately managed data networks that are using IP to transport the calls from one location to the other.

VOIP networks are referred to as "packet-switched networks" because the voicestream (call) is transmitted over the VOIP network in packets.

VOIP is highly efficient because the network is used only when it is actively transporting packets of information. This means that bandwidth is consumed only as needed, thus leaving network resources available for other applications.

VOIP vs. Traditional Phone Service

With traditional phone service, a permanent connection is established for the entire duration of a call. The line or trunk transporting the call is in use while the call is occurring, consuming facilities while delivering the voicestream.

With VOIP, the voicestream is broken down into packets, compressed, and sent toward the final destination by various routes depending on the most efficient path given network availability, congestion, etc…

howvoipworks

VOIP Packet Delivery

When a call is placed on a VOIP network, the first packet contains information about the call and subsequent packets contain the body of the call itself. At the receiving end, the packets are reassembled, decompressed, and converted back into a voice stream by various hardware and software elements, depending on the nature of the call and its final destination.

With VOIP, calls may orginate on a PC (soft phone), an IP phone, an ATA (Analog Telephone Adapter), or other VOIP device, and can be terminated to a PC (soft phone), another IP phone, a traditional PSTN telephone, or other VOIP device.