Section: 6.30.2 Requirements
Content: The following set of requirements complement the requirements listed in 3GPP TS 22.011[ Service accessibility ]  [3], clause 3.2.2.8. The 5G system shall support a mechanism for the HPLMN to control the timing when a UE registered on a VPLMN, in automatic mode (see clause 3.1 of TS 23.122[ Non-Access-Stratum (NAS) functions related to Mobile Station (MS) in idle mode ]  [25]) and currently in CONNECTED mode, enters IDLE mode and initiates higher priority PLMN selection based on the type of ongoing communication. NOTE 1: Changes needed to support the above requirement are expected to have minimum impact on the 5G system. UE is expected to initiate the above-mentioned PLMN selection e.g. by locally releasing the established N1 NAS signalling connection. NOTE 1a: The requirement above applies also to the case of a UE registered to a non-subscribed (standalone) NPN, in order to select a higher priority PLMN or NPN. The UE shall be able to delay conforming to steering of roaming control information from the HPLMN while it is engaged in priority service (e.g. emergency call, MPS session), or a service defined by HPLMN policy not to be interrupted (e.g. MMTEL voice/video call). NOTE 2: The HPLMN policy can take into account the user's preference for the service(s) not to be interrupted. User preferences can be communicated utilizing non-standard operator-specific mechanisms, e.g. web-based. The mechanism mentioned above in this clause shall be available to the HPLMN even if the VPLMN the UE is registered on is compliant to an earlier release of the 5G system. The 5G system shall support mechanisms to enable a credentials holder (e.g. HPLMN or subscribed standalone NPN) to send steering of roaming information to a UE for selecting standalone NPNs (e.g prioritized list of preferred NPNs).