Reference Phone Number: A Secure and QoS-Improved SIP-Based Phone System

With the improvement of the internet and the widespread adoption of digital communication devices such as smartphones, VoIP has largely replaced traditional telephone systems. Many companies are deploying VoIP systems due to their scalability and low cost. In this paper, address the issue of remote clients or traveling employees being unable to contact business partners due to specific phone numbers. We propose a reference phone number mechanism that combines a set of related business partners' phone numbers to enhance call availability. To ensure the confidentiality of calls, we also designed an algorithm to integrate key exchange protocols into the proposed mechanism. The mechanism can flexibly customize the required security protocols. A performance analysis is conducted by deploying the proposed mechanism in a medium-sized company. The results prove that the mechanism is feasible and the effect is satisfactory.