7.4.1 Terminating sessions that use PS media
23.2923GPPIP Multimedia Subsystem (IMS) centralized servicesRelease 17Stage 2TS
7.4.1.1 Full duplex speech via PS
When the ICS UE has access to a PS network that supports the full duplex speech component of an IMS service, terminating IMS procedures (as described in clause 5.7 of TS 23.228 [2]) shall be used to terminate the session to the ICS UE. The S‑CSCF shall insert the SCC AS in the IMS session path using terminating initial filter criteria. The SCC AS shall be the last AS inserted into the session path.