IP Address Translation Mechanisms for SIP-based VoIP

• Main Authors: Ya-Lin Huang, 黃雅琳
• Other Authors: Yi-Bing Lin
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/18473149180982595091

碩士 === 國立交通大學 === 網路工程研究所 === 95 === In Session Initiation Protocol (SIP)-based Voice over IP (VoIP) services, IP addresses are used as location information of User Agents (UAs). The insufficiency of IPv4 addresses becomes a problem in SIP-based VoIP deployment. Deploying Network Address Translators (NATs) into IPv4 networks is one approach so that a public IPv4 address is shared by multiple UAs. However, this approach leads to SIP/Real-time Transport Protocol (RTP) NAT traversing problem. We design and develop a UA that supports the existing SIP/RTP NAT traversing solutions. This UA is used for further analyses and experiments. Another approach is to adopt IPv6 so that every UA owns a unique IPv6 address. Nevertheless, IPv4/IPv6 interworking problem for SIP-based VoIP may occur in the early stage of IPv6 deployment. To solve this problem, we propose an effective solution where the least call setup overhead is introduced and no impairment is incurred to the RTP transmission performance. Our study indicates that none of the existing SIP/RTP NAT traversing solutions is perfect in all aspects. Instead, the usage of IPv6 cooperating with our proposed solution is the best choice with the most efficient performance for deploying SIP-based VoIP services.