关键词: 分层，P2PSIP，跨域，切换

Abstract: This paper presented a scheme of cross-domain hand-off based on hierarchical P2PSIP. It solved the problem about positioning of station which moves among different P2P networks by combining P2P Overlay location with SIP application-layer mobility support. There are usually multiple adjacent P2P networks in a certain area in the actual de- ployment. We specified a standalone P2PSIP network as a domain. An infrastructure of hierarchical P2PSIP network can be adopted to enable stations in different P2P networks to communicate. When a client moves among different P2P networks,we design a set of hand-off procedure to ensure that other stations can locate the mobile one. The stations can communicate with each other directly in the hierarchical P2PSIP network. And mobile station can be located and initiate

Key words: Hierarchical,P2PSIP,Cross domain, Hand-off