Section: 6.4.2 Dedicated EPS bearer context activation procedure 6.4.2.1 General
Content: The purpose of the dedicated EPS bearer context activation procedure is to establish an EPS bearer context with specific QoS and TFT between the UE and the EPC. The network may initiate the dedicated EPS bearer context activation procedure to enable transport of a UE policy container with the length of two octets from the network to the UE and a related UE policy container with the length of two octets from the UE to the network. The UE policy containers with the length of two octets enable transfer of messages of the network-requested UE policy management procedure as specified in 3GPP TS 24.501[ Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3 ]  [54] annex D. In WB-S1 mode, the dedicated EPS bearer context activation procedure is initiated by the network, but may be requested by the UE by means of the UE requested bearer resource allocation procedure (see clause 6.5.3) or the UE requested bearer resource modification procedure (see clause 6.5.4). The dedicated bearer context activation procedure can be part of the attach procedure or be initiated together with the default EPS bearer context activation procedure when the UE initiated stand-alone PDN connectivity procedure. If the attach procedure or the default EPS bearer context activation procedure fails, the UE shall consider that the dedicated bearer activation has implicitly failed. The network may initiate the dedicated EPS bearer context activation procedure together with the completion of the service request procedure. In NB-S1 mode, the dedicated EPS bearer contexts activation procedure is not used. Upon an inter-system mobility from WB-S1 mode to NB-S1 mode in EMM-IDLE mode, if the UE has at least one dedicated EPS bearer context in ESM state BEARER CONTEXT ACTIVE, the UE shall locally deactivate any such dedicated EPS bearer context and shall include the EPS bearer context status IE in TRACKING AREA UPDATE REQUEST message. Upon an inter-system change from WB-N1 mode to NB-S1 mode in EMM-IDLE mode for the UE operating in single-registration mode, the UE shall set each mapped dedicated EPS bearer context, if any, to ESM state BEARER CONTEXT INACTIVE and shall then include the EPS bearer context status IE in the TRACKING AREA UPDATE REQUEST message. NOTE: 3GPP TS 23.060[ General Packet Radio Service (GPRS); Service description; Stage 2 ]  [74] clause 9.3 specifies that a packet filter applicable for the downlink direction is not mandatory in a TFT.