Flexent® IMS — The convergence of circuit and packet core networks

As the Internet model created an environment for creativity and innovation, so, too, will the new Internet protocol multimedia subsystem (IMS) based on the session-initiation protocol (SIP) and Internet protocol (IP) mobile networks. This paper describes Lucent Technologies' innovative architecture that unifies the circuit and IMS domains by providing a single control plane for both. The Flexent® IMS architecture is specifically designed to accomplish this by the deployment of a hardware platform based on the wireless Lucent Softswitch (LSS) that initially supports circuit mobiles and then evolves through software upgrades to support both packet and circuit mobiles off of a common SIP call processing architecture. This evolutionary approach bridges not only the circuit and packet worlds, but brings a common core network architecture that is independent of the access technology, whether it is wireless (CDMA2000^∗ or Universal Mobile Telecommunications System [UMTS]) or wireline (digital subscriber line [DSL], cable modem, or analog modem). This approach truly brings a single set of features and services that can be accessed from anywhere, at anytime, via any access.