Voice Over Internet Protocol Version-4

Voice Over Internet Protocol Version-4

Introduction

Applications involving voice over internet protocol technology:

* Internet Voice Telephony.
* Intranet & Enterprise network voice telephony.
* Internet fax service.
* Multimedia internet collaboration.
* Internet call centers
* PBX intercommunications.

Approaches to deploy Voice Over internet Protocol Network:

* Desktop Approach.
* Shared Approach.

Desktop Approach:

Each individual purchases VOIP enabled terminals used to support remote communications.

Shared Approach:

VOIP capabilities are developed in an industrial strength mode using shared , network-resident servers.

General of VOIP:

Voice signaling protocols have evolved, keeping with the prevalent move from circuit to packet switched networks.
In past, voice analysis & synthesis using a vocoder technology produced a robotic sounding voice, but has changed dramatically during 1990’s.a lot of work is gone into all objective testing of the voice to determine how good the proposed algorithms are. The most frequently used test in  International Telecommunications Union (ITU-T) SG12 is the “Absolute Category Rating”(ACR)test.
Subjects listen to about 8 to 10’s of speech material & are asked to rate the quality of what they heard. Usually 5 point scale is used to represent the quality rating.

Example:
5= Excellent,
1= Bad.
By assigning the corresponding numerical values to each rating, a Mean Opinion Score(MOS) can be computed by each coder by averaging these scores.
Developers & planners are looking at VIOP for intranet & Enterprise Network Applications & enterprise network applications and at VOIP for geographically dispersed applications.
Products  for VOIP are emerging because organizations have significant investments in private data facilities that have the capacity available to carry additional on net traffic what is perceived to be little initial incremental expense.