IP Multimedia (IM) Core Network (CN) subsystem Service Continuity (SC) provides the capability of continuing
ongoing communication sessions with multiple media across different access networks.
This TS provides the protocol details for enabling IMS SC based on the Session Initiation protocol (SIP) and the Session Description Protocol (SDP) and the protocols of the 3GPP Circuit-Switched (CS) domain (e.g. CAP, MAP, ISUP, BICC and the NAS call control protocol for the CS access).
This TS is applicable to User Equipment (UEs), Application Servers (AS), MSC Servers providing IMS
Service Continuity capabilities, Emergency Access Transfer Function (EATF), Access Transfer Control Function
PS to CS SRVCC for emergency session in alerting or pre-alerting phase