A SIP-enabled all-IP architecture for converged next-generation networks

The success of converged next-generation networks (NGNs) will be contingent on the ability of subscribers to access data, voice, and other real-time multimedia services seamlessly, whether they are roaming wireline wide area networks (WWANs) or wireless local area network (WLAN) hot spots. Session Initiation Protocol (SIP) is one of the underlying technologies required to implement an access-agnostic Internet Protocol (IP) multimedia network infrastructure. In this paper, we investigate the key challenges involved in supporting SIP-based real-time (e.g., voice over IP {[}VoIP]) and multimedia services over heterogeneous networks and we describe a SIP-enabled all-IP architecture (SEAR) that leverages 3rd Generation Partnership Project/3rd Generation Partnership Project 2 (3GPP/3GPP2) IP Multimedia Subsystem (IMS) framework, and IETF's SIP profile to support access-independent NGNs. We develop a multilayered policy-based quality of service (QoS) control mechanism and propose an interaction mechanism involving the application service layer, the session control layer, and the transport network layer to support end-to-end consistent QoS and service level agreements (SLAB). We address a SIP-based session control mechanism and the implications for unified service management and describe in detail the end-to-end SIP call flow in an example policy-based network to demonstrate the validity of our solution. We also analyze the interworking architecture between SIP and legacy networks. (C) 2004 Lucent Technologies Inc.