| Instant Messaging (IM) has becoming more popularity in the recent years. As the development of movable equipment such as cell-phone, and3G times of the Telecom World approaching, Instant Messaging is a necessary communication tide nowadays. As one of the core protocols of the Next Generation Network, SIP protocol has many advantages including the separation of service layer and controlling layer, expansion of service, and mobility, to list just a few. It is no doubt that the integration of IM and SIP is an important feature of the future development.While fast developing, the traditional SIP protocols are based on the client-server model, which takes the complex centralized infrastructure. Due to the facts that the data is becoming larger and the equipment running and management require no central facility, the traditional protocols might fail to satisfy such requirements. For this, there is a need to develop new SIP protocols that based on decentralized infrastructure so that the data transport and equipment running could be achieved in a decentralized manner.In this paper, we present a complete SIP protocol description and system design. The protocol is a P2P-over-SIP solution, utilizing SIP both for the transport of P2P messages and personal communications, yielding an interoperable, single-stack solution for P2P communications. To meet the unique security needs of a fully decentralized communications system, we present an enrollment-time certificate authority model that provides asserted identity and user-level security. In this model, a centralized server is contacted only at enrollment time, and no run-time connections to the servers are required. |
PDF Full Text Request