Section: 6.2.14 Handling of Serving PLMN rate control
Content: Serving PLMN rate control is applicable only for PDU sessions established for control plane CIoT 5GS optimization. Serving PLMN rate control protect its AMF from the load generated by user data over control plane. The SMF can inform the UE of any local serving PLMN rate control during the PDU session establishment procedure (see subclause 6.4.1) or the PDU session modification procedure (see subclause 6.4.2). If serving PLMN rate control is enabled, the SMF shall start the serving PLMN rate control for the PDU session when the first control plane user data is received over the PDU session.The UE shall limit the rate at which it generates uplink control plane user data to comply with the serving PLMN policy provided by the network. The indicated rate in a NAS procedure applies to the PDU session the NAS procedure corresponds to, and the indicated rate is valid until the PDU session is released. Any Serving PLMN rate control information provided by the network to the UE is only applicable for the PLMN which provided this information. This serving PLMN rate control information shall be discarded when the UE successfully registers to another PLMN. NOTE: The serving PLMN can discard or delay control plane user data that exceed the limit provided for Serving PLMN rate control.