Section: 4.7.7.2 Serving PLMN Rate Control
Content: The Serving PLMN Rate Control value is configured in the MME. NOTE 1: Homogeneous support of Serving PLMN Rate Control in a network is assumed. At PDN connection establishment, the MME may inform the UE and PDN GW/SCEF (as specified in TS 24.301[ Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS); Stage 3 ]  [46] and TS 29.274[ 3GPP Evolved Packet System (EPS); Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTPv2-C); Stage 3 ]  [43]) of any per PDN connection local Serving PLMN Rate Control that the Serving PLMN intends to enforce for NAS Data PDUs. The MME shall only indicate Serving PLMN Rate Control command to the PDN GW if the PDN connection is using S11-U and set to Control Plane only. The MME shall only indicate Serving PLMN Rate Control command to the SCEF if that PDN connection is using SCEF. This rate control is operator configurable and expressed as "X NAS Data PDUs per deci hour" where X is an integer that shall not be less than 10. There are separate limits for uplink and downlink NAS Data PDUs: - The UE shall limit the rate at which it generates uplink NAS Data PDUs to comply with the Serving PLMN policy. In the UE the indicated rate control applies only on the PDN connection where it was received, and therefore the UE shall limit the rate of its uplink NAS Data PDUs to comply with the rate that is indicated for the PDN connection. The indicated rate is valid until the PDN connection is released. - The PDN GW/SCEF shall limit the rate at which it generates downlink Data PDUs. In the PDN GW/SCEF the indicated rate control applies only on the PDN connection where it was received, and therefore the PDN GW/SCEF shall limit the rate of its downlink Data PDUs to comply with the rate that is indicated for the PDN connection. - The MME may enforce these limits per PDN connection by discarding or delaying packets that exceed this these limits. The Serving PLMN Rate does not include SMS sent via NAS Transport PDUs. The MME starts the Serving PLMN Rate Control when the first NAS Data PDU is received. NOTE 2: If the UE/PDN GW/SCEF start the Serving PLMN rate control at a different time than the MME, PDUs sent within the limit enforced at the UE/PDN GW/SCEF can still exceed the limit enforced by the MME. NOTE 3 It is assumed that the Serving PLMN Rate is sufficiently high to not interfere with the APN Rate Control as the APN Rate Control, if used, is assumed to allow fewer messages. NAS PDUs related to exception reports are not subject to the Serving PLMN Rate Control.