A Low Cost VoIP Architecture for Private Networks

Voice over IP (VoIP) is the future of telephony service which is being widely deployed currently besides the legacy public switched telephone network (PSTN). In this paper we review a minimum cost deployment solution for VoIP for private networks using available open source tools with considering the fact that currently private networks are mostly behind the NAT and the fact that in this case VoIP calls cannot be initiated from outside the private network. We provide a solution to resolve this problem in which unlike other available solutions the data packets do not need to pass through a proxy server.