Research And Implementation Of Highly Secure Voip System

Currently, the voice encryption technology based traditional PSTN has matured, related products such as telephone encryption machine has been widely used in key sectors, because of circuit-switched system and modem performance limitations, there are still some defects in the use and management of such products. Meanwhile, with the continuous development of network technology, the traditional PSTN to packet-switched network is gradually changed. In fact, many important departments have set up their own private IP networks for daily office and communications, and many companies also use IP PBX and other equipments in the formation of IP telephone system on the Internet, IP networks are rapidly marginalized, voice communication using IP networks is a trend. So, how to build a high-security telephone system using existing IP network and technology to meet important users’urgent communication needs, that’s we need to study and solve.This paper aims to build high-security VoIP systems on existing private and public networks. First, appropriate VoIP system architecture and protocols were studied and selected. Next, many problems VoIP facing were studied, including Qos, NAT traversal, security threats; focusing on the security aspects, technologies as IP sec, VPN, VLAN, sip protection were deeply studied, and a solution addressing these issues in favor of project goals was identified. According to Above-mentioned research works, a whole solution constructing a high-security VoIP system on private and public networks was Proposed, with verifying and elaborating realization or improvement for key technologies such as access authentication, call connection security, media encryption according to a project author involved in.The main feature of this paper is the target that based on the formation of practical, safe, low cost VoIP system. After having deeply studied relevant issues and technologies, and having determined the response and technical solutions, this paper proposed a whole solution of VoIP system meeting target from point to surface, with having achieved some key technologies. This study also has some help and guidance to the formation of similar systems and development of related equipment.