Using P2P Overlay to Improve VoIP Quality in SIP+P2P System

The Current Internet provides a Best-effort service, which can not satisfy service quality guarantees that VoIP systems often require. Systems such as multi-homing and overlay network leverage path diversity that Internet inherently has to enhance end-to-end application performance. In this paper, we propose a P2P overlay approach, which is used to transmit media stream in SIP+P2P system. SIP+P2P is a Peer-to-Peer VoIP system, which leverages potential path diversity provided by P2P overlay to enhance VoIP quality. Firstly, we propose a path selection mechanism to ensure that end-to-end paths have a high degree of diversity. Then we develop an effective path switching mechanism based on P2P overlay, including path quality evaluation, predicting, and application-driven path switching. Finally, we evaluate our design on our SIP+P2P testbed, and prove that our path selection can explore high path diversity and that path switching can improve VoIP quality effectively.