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Voice
over Internet Protocol
(VoIP) is a general term for a family of transmission
technologies for delivery of voice communications over IP
networks such as the Internet or other packet-switched networks.
Other terms frequently encountered and synonymous with VoIP are
IP telephony, Internet telephony, voice over
broadband (VoBB), broadband telephony, and
broadband phone.
VoIP systems usually interface
with the traditional public switched telephone network (PSTN) to
allow for transparent phone communications worldwide.
VoIP systems employ session
control protocols to control the set-up and tear-down of calls
as well as audio codecs which encode speech allowing
transmission over an IP network as digital audio via an audio
stream. Codec use is varied between different implementations of
VoIP (and often a range of codecs are used); some
implementations rely on narrowband and compressed speech, while
others support high fidelity stereo codecs.
VoIP
Implementations
Voice over IP has been
implemented in various ways using both proprietary and open
protocols and standards. Examples of available VoIP
implementations include:
Benefits:
Operational cost
VoIP can be a benefit for
reducing communication and infrastructure costs. Examples
include:
- Routing phone calls over
existing data networks to avoid the need for separate voice
and data networks.
- Conference calling, IVR,
call forwarding, automatic redial, and caller ID features that
traditional telecommunication companies (telcos) normally
charge extra for are available for free from open source VoIP
implementations such as Asterisk.
Flexibility
VoIP can facilitate tasks and
provide services that may be more difficult to implement using
the PSTN. Examples include:
- The ability to transmit more
than one telephone call over the same broadband
connection.This can make VoIP a simple way to add an extra
telephone line to a home or office.
- Secure calls using
standardized protocols (such as Secure Real-time Transport
Protocol.) Most of the difficulties of creating a secure phone
connection over traditional phone lines, like digitizing and
digital transmission, are already in place with VoIP. It is
only necessary to encrypt and authenticate the existing data
stream.
- Location independence. Only
an Internet connection is needed to get a connection to a VoIP
provider. For instance, call center agents using VoIP phones
can work from anywhere with a sufficiently fast and stable
Internet connection.
- Integration with other
services available over the Internet, including video
conversation, message or data file exchange in parallel with
the conversation, audio conferencing, managing address books,
and passing information about whether others (e.g., friends or
colleagues) are available to interested parties.
Other Communication /
Telecommunication Categories:
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