The IP multimedia subsystem (IMS) specifies a service centric framework for converged, all-IP networks. This promises to provide the long awaited environment for deploying technology-neutral services over fixed, wireless, and cellular networks, known as third generation (3G) networks. Since its initial proposal in 1999, the IMS has gone through different stages of development, from its initial Release 5 up to the current Release 7.
Key Terms in this Chapter
IMS Service Provisioning: Service provisioning in the IMS offers the required mechanisms for execution, control, and integration of services in the IMS.
Presence Service: This allows for the collection of various forms of information on the characteristics of the network, users, and terminals. Users can subscribe or be notified of this information.
Open Service Architecture (OSA): The OSA is the defined architecture that allows operator and third party applications to make use of the underlying network functionalities through standardized, open interface.
Service Integration: This is the integration of both real-time and non-real time services to more complex and attractive “bundled services.”
Application Servers: Application servers are used to host and execute the services used in the IMS network.
IMS Session Management: Sessions management is based on creation, modification, integration, and modification of conventional SIP messages.
Services Capabilities: These are standardised mechanisms needed to realise services within the IMS network and under the network control.