Asynchronous distributed P2P-SIP model for VoIP

The critical issue of P2P models for supporting Internet telephony are: users localization and their ldquoasynchronousrdquo nature. In this paper, we propose a new P2P-SIP architecture for Internet telephony; aims to support the asynchronous model that generally characterized P2P systems. The purpose is to optimize the global end-to-end delay, which is one of the main performance metrics for telephony. Our approach is based on an optimal combination of chord and SIP protocols. Chord constitutes the overlay network plan, while SIP provides the signalling plan. The proposed approach is based on a global shared delay matrix for calculating the shortest path from source S to destination D, it can be easily extended to support advanced services such as off-line messaging, multiparty conferencing, media routing and NATs / firewalls detection and traversal. The proposed model which benefits from chord and SIP characteristics is shown to be scalable, fault tolerant and interoperable. Performance evaluations show that the preliminary results are globally satisfactory.