| Voice
Over Internet Protocol |
Definition
Using an ordinary phone for most people is a common daily occurrence as is listening
to your favorite CD containing the digitally recorded music. It is only a small
extension to these technologies in having your voice transmitted in data packets.
The transmission of voice in the phone network was done originally using an analog
signal but this has been replaced in much of the world by digital networks. Although
many of our phones are still analog, the network that carries that voice has become
digital. In todays phone networks, the analog
voice going into our analog phones is digitized as it enters the phone network.
This digitization process, shown in Figure 1 below, records a sample of the loudness
(voltage) of the signal at fixed intervals of time. These digital voice samples
travel through the network one byte at a time.
At the destination phone line,
the byte is put into a device that takes the voltage number and produces that
voltage for the destination phone. Since the output signal is the same as the
input signal, we can understand what was originally spoken.
The evolution
of that technology is to take numbers that represent the voltage and group them
together in a data packet similar to the way computers send and receive information
to the Internet. Voice over IP is the technology of taking units of sampled speech
data .
So at its most basic level, the concept of VoIP is straightforward.
The complexity of VoIP comes in the many ways to represent the data, setting up
the connection between the initiator of the call and the receiver of the call,
and the types of networks that carry the call. Using
data packets to carry voice is not just done using IP packets. Although it won't
be discussed, there is also voice over Frame Relay (VoFR) and Voice over ATM (VoATM)
technologies. Many of the issues VoIP being discussed also apply to the other
packetized voice technologies.
The increasing multimedia contents in Internet
have reduced drastically the objections to putting voice on data networks. Basically,
the Internet objections to putting voice on data networks. Basically, the Internet
Telephony is to transmit multimedia information in discrete packets like voice
or video over Internet or any other IP-based Local Area Network (LAN) or Wide
Area Network (WAN). The commercial Voice Over IP (Internet Protocol) was introduced
in early 1995 when VocalTec introduced its Internet telephone software. Because
the technologies and the market have gradually reached their maturity, many industry
leading companies have developed their products for Voice Over IP applications
since 1995
VoIP, or "Voice over Internet Protocol" refers to sending
voice and fax phone calls over data networks, particularly the Internet. This
technology offers cost savings by making more efficient use of the existing network. Traditionally,
voice and data were carried over separate networks optimized to suit the differing
characteristics of voice and data traffic. With advances in technology, it is
now possible to carry voice and data over the same networks whilst still catering
for the different characteristics required by voice and data.
Voice-over-Internet-Protocol
(VOIP) is an emerging technology that allows telephone calls or faxes to be transported
over an IP data network.
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