H.1 General

23.1673GPPIP Multimedia Subsystem (IMS) emergency sessionsRelease 17TS

This annex includes additional requirements and clarifications when the IP-CAN is a PS Domain supporting UTRAN, E-UTRAN or NG-RAN radio access network.

NOTE: For SNPN, as defined in TS 23.501 [48] the only supported RAT is NR and there is no support for Emergency Services Fallback.

If a PLMN supports other emergency numbers than those listed in TS 22.101 [8], the UE is connected to the PLMN using UTRAN, E-UTRAN or NG-RAN radio access network and the UE needs to know these other emergency numbers, then such emergency numbers shall be provided to the UE via the mobility management procedures as described in TS 24.301 [33], TS 24.008 [13] and TS 24.501 [52].

If an SNPN supports other emergency numbers than those listed in TS 22.101 [8], the UE is connected to the SNPN using NR access and the UE needs to know these other emergency numbers, then such emergency numbers shall be provided to the UE via the mobility management procedures as described in TS 24.501 [52].

For registration requests received from an emergency PDN connection or emergency PDU session, the P-CSCF shall reject any IMS registration which is not for the emergency purpose.

eCall is supported with E-UTRAN and NG-RAN for PLMNs only, i.e. eCall is not supported for SNPNs. UE configured for eCall Only Mode can receive a PSAP call back for a limited duration following the termination of the eCall due to its specific mobility management procedures requirement as defined in TS 22.101 [8].