In this paper, we propose a hierarchical and heterogeneous P2P-SIP architecture, which is independent of the underlying DHT overlay and makes the combination of P2P and SIP practical. Peers who work in heterogeneous overlays, i.e. Chord, Kademlia and Pastry, can intercommunicate with other peers who are in different overlay via a decentralized manner provided by the hierarchical P2P-SIP architecture. Some nodes in the overlay are proposed to be stateful to improve the reliability of the overlay. Finally, a session initial example is presented to illustrate this architecture.