Section: 5.40 Support of Disaster Roaming with Minimization of Service Interruption 5.40.1 General
Content: Subject to operator policy and national/regional regulations, 5GS provides Disaster Roaming service (e.g. voice call and data service) for the UEs from PLMN(s) with Disaster Condition. The UE shall attempt Disaster Roaming only if: - there is no available PLMN which is allowable (see TS 23.122[ Non-Access-Stratum (NAS) functions related to Mobile Station (MS) in idle mode ]  [17]); - the UE is not in RM-REGISTERED and CM-CONNECTED state over non-3GPP access connected to 5GCN; - the UE cannot get service over non-3GPP access through ePDG; - the UE supports Disaster Roaming service; - the UE has been configured by the HPLMN with an indication of whether Disaster roaming is enabled in the UE set to "disaster roaming is enabled in the UE" as specified in clause 5.40.2; and - a PLMN without Disaster Condition is able to accept Disaster Inbound Roamers from the PLMN with Disaster Condition. In this Release of the specification, the Disaster Condition only applies to NG-RAN nodes, which means the rest of the network functions except one or more NG-RAN nodes of the PLMN with Disaster Condition can be assumed to be operational.