TTL-Based UDP Hole Punching Scheme in SIP Network

In this paper, we propose the low Time-To-Live (TTL)-based UDP hole punching scheme to reduce the load on the SIP registrar for Network Address Translator (NAT) traversal. For this purpose, the low TTL value is determined by executing ‘traceroute’ for the server reflexive IP address obtained through the SIP registration. In the proposed scheme, since the UDP hole punching request with low TTL value will never reach the registrar, the load on the registrar can be significantly alleviated. We analyze the proposed scheme using the Markov chain model. Numerical results indicate that the proposed scheme can significantly alleviate the load on the registrar, compared to the existing SIP scheme.