K.4 Non UE detectable Emergency Session

23.1673GPPIP Multimedia Subsystem (IMS) emergency sessionsRelease 17TS

In addition to clause 7.1.2, the following is applicable for this scenario:

– It is recommended that local emergency call numbers are provided to the UE according to the procedures specified in TS 24.501 [52], TS 24.301 [33], TS 24.008 [13] or Annex J.2. This helps to reduce the number of non-UE detected emergency numbers even for those PLMNs where only a subset of the local emergency numbers can be downloaded to the UEs.

– When the UE registers in the IMS, the P-CSCF may retrieve the VPLMN-ID or SNPN ID of the UE as described in clause W.3 of TS 23.228 [1] and may access a database to obtain a list of all local emergency numbers for the visited PLMN, if not already available in the P-CSCF. These numbers are used for detection of non UE detectable emergency calls during IMS session setup. The database of PLMN-/SNPN- specific emergency numbers and its interface with the P-CSCF are not specified by 3GPP.

Annex L (normative):
IMS emergency services using non-3GPP access to 5GC