The IMS based service control is responsible for audio/video telephony SIP signalling, SIP message routing, user registration and for 3GPP IMS compatible service control and service triggering. The S-CSCF (Call Session Control Function) evaluates user attached profiles with all services the user is subscribed to, determines if services should be triggered based upon IFC (Initial Filter Criterias) and initiates service execution at the service providing application servers (AS).

By the use of IMS based service control we can assure that IPTV as a service can interact and can be combined with other non-IPTV but IMS based services.

The S-CSCF is provided by SPIN, a SIP Proxy for IMS Networks developed at DAI-Labor. SPIN is a platform for 3GPP IMS core functionalities like S-CSCF, I-CSCF and P-CSCF. In addition SPIN can simply be used as a SIP Server, including redirect, registrar and proxy functionalities.