ISC
IP multimedia subsystem Service Control interface
The ISC connects the S-CSCF to the Application Server supported either in the 3GPP Home PLMN or a third party network and is based on SIP. The AS may influence the session or service being provided by the S-CSCF across the ISC. In terms of the logic provided by the service environments the ISC will present this in a consistent format to the S-CSCF through a series of SIP methods and responses.