P2P architecture for IP telephony using SIP

Session Initiation Protocol (SIP) is a control protocol stan-dardized by IETF and implemented on the application layer. It can be used to establish, modify, and terminate Inter-net conferencing, telephony and some other multimedia sessions.[1] SIP uses server and client architecture, Peer-to-Peer (P2P) is another popular technology that accomplishes the same functionality in an overlay network where partici-pants are organized as equally important peers. This paper gives a brief introduction to the motivation for P2P-SIP and the requirements for setting up its structure. Secondly, two design alternatives of P2P-SIP architectures are introduced based on the current level. It explains how the SIP-based IP telephony system utilizes the P2P architecture. The pa-per concludes with a brief look at the limitations of the P2P Internet telephony using SIP and suggests further work is re-quired