Section: 4.3.17.4 UE configuration and usage of indicators
Content: A subscriber can by agreement with its operator be required to use UEs that are configured (see TS 24.368[ Non-Access Stratum (NAS) configuration Management Object (MO) ]  [69]) to support one or more of the following options: - UE configured for low access priority; and/or - UE configured with a permission for overriding low access priority, which is only applicable for a UE that is also configured for low access priority; and/or - UE configured to perform Attach with IMSI at PLMN change; and/or - UE configured with a long minimum periodic PLMN search time limit; and/or - UE configured for specific handling of the invalid USIM state, the "forbidden PLMN list", the "forbidden PLMNs for attach in S1mode list" and the "forbidden PLMNs for GPRS service list"; and/or - UE configured for Extended Access Barring; and/or - UE configured with a permission for overriding Extended Access Barring, which is only applicable for a UE that is also configured for Extended Access Barring. NOTE 1: When a UE is accessing the network with low access priority, then the UE may be subject for longer backoff timers at overload and consequently need to be designed to be tolerant to delays when accessing the network. UEs can be configured for one or more of the above options with the following restrictions: - in this Release of the specification, a UE that is configured for low access priority shall also be configured for Extended Access Barring; and - in this Release of the specification, a UE that is configured for Extended Access Barring shall be configured for low access priority. - in this Release of the specification, a UE that is configured for overriding low access priority shall also be configured for overriding Extended Access Barring; and - in this Release of the specification, a UE that is configured for overriding Extended Access Barring shall also be configured for overriding low access priority. UEs can be configured for one or more of the above options. Post-manufacturing configuration of these options in the UE can be performed only by OMA DM or (U)SIM OTA procedures. UEs capable of the above options should support configuration of these options by both OMA DM and (U)SIM OTA procedures. A UE configured for low access priority shall transmit the low access priority indicator to the MME during the appropriate NAS signalling procedures and transmit the corresponding low access priority to the E-UTRAN during RRC connection establishment procedures. NOTE 2: The low access priority indicator in NAS signalling and the corresponding low access priority for RRC connection establishment are used by the network to decide whether to accept the NAS request or the setup of the RRC connection respectively. Low access priority shall not be applicable in the following situations: - for all procedures related to an emergency PDN connection; used for IMS Emergency sessions that are to be prioritized as per the requirements for IMS Emergency session procedures (see clause 4.3.12). When an emergency PDN connection gets established, the MME may, based on MME configuration, initiate the deactivation of any non-emergency PDN connection using the MME requested PDN disconnection procedure described in clause 5.10.3; - for all procedures when preferential access to the network is provided to the UE by the Access Class 11-15 mechanism according to TS 36.331[ Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification ]  [37] and TS 22.011[ Service accessibility ]  [67] e.g. for Multimedia Priority Services as described in clause 4.3.18; NOTE 3: The configuration of a UE for low access priority and Access Class 11-15 are configured independently of each other. However, the home operator can take care to prevent a subscription for Access Class 11-15 from being used in a UE configured for low access priority. - for RRC connection establishment procedures when responding to paging; - for a UE configured with a permission for overriding low access priority under conditions described by bullet o in clause 4.3.17.2; or - other specific situations described in TS 24.301[ Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS); Stage 3 ]  [46]. If the NAS session management request message used to establish a new PDN connection contains a low access priority indication, the MME shall forward the low access priority indication in the Create Session Request message to the S-GW/P-GW. The low priority indication gets associated with a PDN connection when it is established and it shall not change until the PDN connection is deactivated. The low access priority indication may be included in charging records by the visited and home networks. In order to permit the S-GW to include the low access priority indicator in the charging records, the low access priority indicator should be stored in the MME EPS Bearer contexts and should be passed as part of these contexts to other SGSN/MME or S-GW nodes in mobility management procedures. NOTE 4: In this release there is no other usage of storing the low access priority indicator in EPS Bearer contexts other than for the purpose to include it in charging records. Particularly, the low access priority indicator in EPS Bearer contexts is not used by the network to make overload control decisions. A network node may invoke one or more of the following mechanisms based on the indicators received in signalling from UEs or forwarded by other network nodes: - based on the low access priority indicator in NAS request messages, bullets e, h, i, k and l as defined in clause 4.3.17.2; and/or - based on the low access priority for RRC connection establishment, bullets b, c and q as defined in clause 4.3.17.2. A UE shall invoke one or more of the following mechanisms based on the configuration and capabilities of the UE: - when UE is configured with a long minimum periodic PLMN search time limit, the UE invokes actions as described in bullet f in clause 4.3.17.2; and/or - when UE is configured to perform Attach with IMSI at PLMN change, the UE invokes actions as described in bullet g in clause 4.3.17.2; and/or - when a UE is configured for low access priority, the UE invokes actions as described in bullets b and h in clause 4.3.17.2; and/or - when UE is configured for specific handling of the invalid USIM state, the "forbidden PLMN list", the "forbidden PLMNs for attach in S1mode list" and the "forbidden PLMNs for GPRS service list", the UE invokes actions as defined in bullet n in clause 4.3.17.2; and/or - when UE is configured for Extended Access Barring, the UE invokes actions as defined in bullet d in clause 4.3.17.2; and/or - when a UE is configured with a permission for overriding low access priority and configured with a permission for overriding Extended Access Barring, the UE invokes actions as described in bullets o) and p) in clause 4.3.17.2.