A P2P Approach to SIP Registration and Resource Location

This document outlines the motivation and requirements for a Peer-to- Peer (P2P) based approach for SIP registration and resource discovery using distributed hash tables and presents the architectural design for such a system. This design removes the need for central servers from SIP, while offering full backward compatibility with SIP, allowing reuse of existing clients, and allowing P2P enabled peers to communicate with conventional SIP entities. A basic introduction to the concepts of P2P is presented, backward compatibility issues addressed, and the security considerations are considered. This work is one possible implementation of the the protocol being discussed for creation in the proposed P2PSIP WG. In the context of the work being proposed, this draft would represent a concrete proposal for the P2PSIP Peer Protocol, using modified SIP as the underlying protocol. In this architecture, no P2PSIP Client Protocol is needed, rather unmodified SIP is used for access by non-peers. This is early work, and is less secure in many ways than the traditional approach to SIP, but has certain other interesting characteristics that may make it desirable in some situations. This work is being discussed on the p2psip@cs.columbia.edu mailing list.