Design and configuration of VoIP based PBX using asterisk server and OPNET platform

The advent of Voice over IP (VoIP) telephony has revolutionized the world of telecommunication. It has opened several possibilities of extending the traditional telephony concepts. Advancement in software has made it possible to implement various telephony hardware functions in software. Asterisk, a Linux based implementation of PBX is considered as a key addition to the revolution in the modern telephony. This paper is aimed at to develop a campus -wide VoIP based network. The Asterisk will configured with the function to support Auto-attendant, call parking, call conferencing, call on hold, voicemail, music on hold and email notification. The project involves the use of various softphones and their configuration. The system will be then test using various call loads for different voice codecs. The results of different codecs were compared to each other to select the best codec for Asterisk PBX. The same network will be simulated in OPNET (network simulator) and the codecs result of Asterisk will be compare with that of OPNET result to find which codec result is more closed to real environment result.