Section: 5.16.3 IMS support 5.16.3.1 General
Content: IP-Connectivity Access Network specific concepts when using 5GS to access IMS can be found in TS 23.228[ IP Multimedia Subsystem (IMS); Stage 2 ]  [15]. 5GS supports IMS with the following functionality: - Indication toward the UE if IMS voice over PS session is supported. - Capability to transport the P-CSCF address(es) to UE. - Paging Policy Differentiation for IMS as defined in TS 23.228[ IP Multimedia Subsystem (IMS); Stage 2 ]  [15]. - IMS emergency service as defined in TS 23.167[ IP Multimedia Subsystem (IMS) emergency sessions ]  [18]. - Domain selection for UE originating sessions. - Terminating domain selection for IMS voice. - Support of P-CSCF restoration procedure (clause 5.16.3.9). - NRF based P-CSCF discovery (clause 5.16.3.11). NOTE: The NRF based P-CSCF discovery has no impact on the UE, i.e. the UE does not need to know how P-CSCF IP address(es) is discovered in the network. - NRF based HSS discovery (clause 5.16.3.12).