Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); LTE; IMS Restoration Procedures (V15.0.0; 3GPP TS 23.380 version 15.0.0 Release 15)
The present document specifies the procedures required in 3GPP IMS to handle a S-CSCF or a P-CSCF service interruption scenario with minimum impact to the service to the end user. NOTE: IMS Restoration Procedures covering service interruption of other network elements are not defined in this version of the specification.