The goal of the implementation of a VoIP system is quite simple. It is to add telephone-calling capabilities to IP-based networks. Then it interconnects them to the public telephone network and to private voice networks to maintain voice quality standards and preserve the features users expect from their telephones.
A VoIP system should have specific characteristics:
Voice quality should be comparable to what is available using the PSTN, even over networks with variable levels of QoS.
The underlying IP network must meet strict performance criteria, including minimal call refusals, network latency, packet loss, and disconnects. This goal should be met even during congested periods or when multiple users must share ...