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Internet
Telephony, also known as IP Telephony, is for any telephony
application that can be enabled across a data network
via the Internet Protocol.
Internet Telephony is created by the merging of
the circuit-switched and packet-switched world. In the
past, real-time voice information is sent over the Public
Switched Telephone Network (PSTN). With the circuit-switched
technology, every call takes up a dedicated bandwidth.
End-to-end calls are established on the basis of a sequence
of dialed digits, and the PSTN dedicates a physical path
between callers. Although the telephone equipment establishes
the call path at the beginning of the call, the path may
change between calls, but not during any specific call.
In comparison with a PSTN, an Internet Protocol
(IP) network or Internet Telephony network has a packet-switched
architecture. Devices transmit data in packets, and the
path from end to end can vary within an established session.
In addition to data, packets also contain addressing information,
which routing devices used to send information to its
destination. Routing devices maintain tables which instruct
them how to direct packets. As networking environments
change, routing devices are updated with dynamic protocols.
Traditionally the PSTN was the only network supporting
voice communication. With Internet Telephony, voice, fax,
data, and video can be sent over IP-based packet-switched
networks. There are also many Internet Telephony applications
such as web-enabled Interactive Voice Response (IVR),
Unified Messaging, intelligent Private Branch Exchanges
(PBXs) and much more Internet Telephony applications being
invented due to the merging of computer and telephony
technology. The term Computer Telephony Integration (CTI)
is now becoming increasing popular and there will be series
of applications, which are now under development, to meet
the growing demands for new technologies. |