An efficient approach for NAT traversal problem on security of voice over internet protocol

This paper evaluates an efficient approach for network address translation (NAT) problem on voice over Internet protocol (VoIP) network system. Based on our experiment, we examined the latency, buffer size and voice packet loss under various network conditions. We found that it is possible to establish a call from outside the NAT to inside maintaining the quality issues of VoIP call. With this approach it is possible to use the current network architecture with having few changes in the registrar server. Based on this result, we propose a model for VoIP system that eliminates NAT traversal problem of VoIP call setup. Hence we evaluate our model showing the QoS conditions that achieves both high efficiency and secure voice transmission.