A Serving-CSCF (S-CSCF) is the central node of the signaling plane. It is a SIP server, which also performs session control. It uses Diameter Cx and Dx interfaces to the HSS to download and upload user profiles - it has no local storage of the user. All necessary information is loaded from the HSS. Handles SIP registrations, which allows it to bind the user location and the SIP address Decides the destination application servers to which the SIP message will be forwarded, in order to provide the services Provides routing services, by using Electronic Numbering lookups it enforces the policy of the network operator.
OSIMS SCSCF component is based on Open IMS Core.