SIP over Peer-to-Peer — Implications and existing approaches

In contemporary communication system, Peer-to-Peer Session Initiation Protocol (P2PSIP) is the forthcoming migration from the traditional client-server based SIP system. Traditional centralized server based SIP system is vulnerable to several problems like performance bottleneck, single point of failure. So, integration of Peer-to-Peer system (P2P) with Session Initiation Protocol (SIP) will improve the performance of a conventional SIP system because a P2P system is highly scalable, robust, and fault tolerant because of its decentralized manner and self-organization of the network. However, P2PSIP architecture faces several challenges including trustworthiness of peers, resource lookup delay, Network Address Translation (NAT) traversal, etc. This paper focuses on understanding the needs of integration of P2P and SIP. It reviews the existing approaches to identify how they have integrated P2P and SIP and solved the challenges introduced by P2PSIP.