call session control function (NGN, IMS) (CSCF)

Call Session Control Function (CSCF) is a central component of the IPMultimedia Subsystem(IMS). The CSCF is a control function in Next Generation Networks( NGN) that performs the control and monitoring functions for the connection status.

The CSCF function establishes, coordinates, monitors, and initiates multimedia sessions between IP networks and UMTS, between mobile and fixed users, between the Internet and smartphones, and supports all multimedia services: voice, data, browsing, video. There is the S-CSCF, the Serving SCSF, which registers users and controls the SIP connection, services and service features. For this purpose, it communicates with user equipment and application servers. The S-CSCF are supported by the I-CSCF, Interrogating-CSCF, which are responsible for load balancing in the network. The I-CSCF receives its information from the UMTS network.

The transition between an Internet Multimedia Domain( IM domain) and a GatewayGPRS Support Node( GGSN) is realized by the Proxy-CSCF (P-CSCF).