Next-generation application delivery architecture. In the IMS architecture, applications can be created, controlled and changed, regardless of the kind of network or platform on which they run. IMS promises to bring flexibility, operational effectiveness, openness and standardization to the delivery of applications across fixed and mobile networks. It specifies a Session Initiation Protocol (SIP)-based control layer, with open interfaces to the transport and services layers above, and has a centralized end-user profile depository. IMS is aimed at bringing improved interoperability among networks and offers carriers control over applications on a per-session basis for increased flexibility. There are three logical elements within the IMS architecture: the session control layer, the interworking or gateway layer and the application layer.