Section: 4.12 Access traffic steering, switching and splitting (ATSSS)
Content: The ATSSS feature is an optional feature that may be supported by the UE and the 5GCN. The ATSSS feature enables a multi-access PDU connectivity service, which can exchange PDUs between the UE and a data network by simultaneously using one 3GPP access network and one non-3GPP access network. The multi-access PDU connectivity service is realized by establishing a multi-access PDU session, i.e. a PDU session that can have user-plane resources on two access networks. NOTE: MA PDU session is not applicable for CIoT 5GS optimization in this release of specification. The UE can request an MA PDU session when the UE is registered via both 3GPP and non-3GPP accesses, or when the UE is registered via one access only. The MA PDU session management is performed based on the PDU session management procedures. The detailed description of the procedures for ATSSS between the UE and the network across one 3GPP access network and one non-3GPP access network are specified in 3GPP TS 24.193[ 5G System;Access Traffic Steering, Switching and Splitting (ATSSS); Stage 3 ]  [13B].