Abstract
It has been shown in previous work that session setup delays in a Peer-to-Peer Session Initiation Protocol (P2PSIP) based Voice over IP (VoIP) system can be unacceptably high. This is due to the need to route several messages across the P2P overlay and also due to the fact that P2PSIP needs to establish separate connections for SIP signaling and Real-Time Protocol (RTP) media between the communicating parties across Network Address Translators (NATs). In this paper, we will develop optimizations to reduce P2PSIP session setup delays. We will also analyze the performance of these optimizations. Using the proposed optimizations, it is possible to achieve delays that are up to three times lower than those of unoptimized P2PSIP.