Section: 4.3.23a Access network selection and traffic steering based on RAN-Controlled WLAN interworking
Content: As described in TS 36.300[ Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 ]  [5] E-UTRAN may support RAN-Controlled WLAN interworking (RCLWI) for controlling traffic steering between E-UTRAN and WLAN for UEs in RRC_CONNECTED. When E-UTRAN sends an "offload" command to the UE, the UE passes an indication to the upper layers indicating that traffic steering to/from WLAN is needed. The upper layers determine to initiate traffic steering to/from WLAN based on the UE capability and the configuration information that has received from NAS layer indicating which PDN connections are offloadable. When the UE receives the "offload" command from the EUTRAN, the UE shall perform handover to WLAN only the PDN connections that have been authorized for offloading. The NAS level indication about "offloadability" of PDN connections is defined in clause 4.3.23. The UE uses the RCLWI procedures to perform access network selection and traffic steering decisions between 3GPP access and WLAN or using ANDSF policies defined in TS 23.402[ Architecture enhancements for non-3GPP accesses ]  [2]. Co-existence between the procedures defined for RCLWI, ANDSF policies and user preference is described in TS 23.402[ Architecture enhancements for non-3GPP accesses ]  [2].