Transit-Stub Architecture for Peer-to-Peer SIP

A transit-stub P2PSIP architecture is proposed in this paper. In this architecture, heterogeneous P2PSIP overlays are interconnected in a decentralized approach provided by a transit overlay. A special SIP element, P2PSIP router, is designed to exchange SIP routing information and route SIP messages. Our architecture reacts to the change of route information quickly. Performance analysis indicates that session setup latency and register overhead are significantly reduced compared to those of the flat P2PSIP approach when applying the locality based grouping scheme. Finally, we describe deployment scenarios for the architecture and present our implementation.