VPN Analysis and New Perspective for Securing Voice over VPN Networks

Security and privacy become mandatory requirements for VoIP communications that needs security services such as confidentiality, integrity, authentication, non-replay and non- repudiation. The available solutions are generic and do not respect voice specificities and constraints. Thus, QoS of the voice is affected by delay, jitter, and packet loss. New security solutions must take into account the real-time constraint of voice service and their mechanisms should address possible attacks and overhead associated with it. Nowadays, VPNs (Virtual Private Networks) is considered the strongest security solutions for communications over IP networks. Most VPN solutions are implemented to tunnel data traffic while the trend toward a converged data and voice network, however, places new demands on VPNs to support real time traffic. In this paper we compare the VPN security protocols presenting their advantage and drawbacks. Then we present our new solution to secure voice over IPSec VPNs while guaranteeing the performance and quality of services, without reducing the effective bandwidth. We use the AVISPA model to analyze the security vulnerabilities of exchange messages to initiate session and establish VPN.