Content for  TS 23.501  Word version:  17.4.0

The Network Analytics architecture is defined in TS 23.288.

In order to support the ATSSS feature, the 5G System Architecture is extended as shown in Figure 4.2.10-1, Figure 4.2.10-2 and Figure 4.2.10-3. The additional functionality that is supported by the UE and the network functions shown in these figures is specified in clause 5.32 below. In summary:

• The UE supports one or more of the steering functionalities specified in clause 5.32.6, e.g. MPTCP functionality and/or ATSSS-LL functionality. Each steering functionality in the UE enables traffic steering, switching and splitting across 3GPP access and non-3GPP access, in accordance with the ATSSS rules provided by the network. The ATSSS-LL functionality is mandatory in the UE for MA PDU Session of type Ethernet.
• The UPF may support MPTCP Proxy functionality, which communicates with the MPTCP functionality in the UE by using the MPTCP protocol (RFC 8684).
• The UPF may support ATSSS-LL functionality, which is similar to the ATSSS-LL functionality defined for the UE. There is no user plane protocol defined between the ATSSS-LL functionality in the UE and the ATSSS-LL functionality in the UPF. The ATSSS-LL functionality in the UPF is not shown in the following three figures.
• In addition, the UPF supports Performance Measurement Functionality (PMF), which may be used by the UE to obtain access performance measurements (see clause 5.32.5) over the user-plane of 3GPP access and/or over the user-plane of non-3GPP access.
• The AMF, SMF and PCF are extended with new functionality that is further discussed in clause 5.32.

Figure 4.2.10-2 shows the 5G System Architecture for ATSSS support in a roaming case with home-routed traffic and when the UE is registered to the same VPLMN over 3GPP and non-3GPP accesses. In this case, the MPTCP Proxy functionality and the PMF are located in the H-UPF.

Figure 4.2.10-3 shows the 5G System Architecture for ATSSS support in a roaming case with home-routed traffic and when the UE is registered to a VPLMN over 3GPP access and to HPLMN over non-3GPP access (i.e. the UE is registered to different PLMNs). In this case, the MPTCP Proxy functionality and the PMF are located in the H-UPF.

The architecture for 5G multicast-broadcast services is defined in TS 23.247.

The architecture for Proximity based Services (ProSe) in the 5G System is defined in TS 23.304.

The architecture enhancements for edge computing are outlined in clause 5.13 and further described in TS 23.548.

The architecture for Support of Uncrewed Aerial Systems (UAS) connectivity, identification and tracking is defined in TS 23.256.

The reference architecture shown in Figure 4.2.15-1 enables a UE to connect to a WLAN access network using its 5GS credentials without registration to 5GS. This architecture is based on the Non-Seamless WLAN Offload Function (NSWOF), which interfaces to the WLAN access network using the SWa interface as defined in TS 23.402, and interfaces to the AUSF using the Nausf Service Based Interface (SBI). The functionality of NSWOF and the procedures applied for supporting WLAN connection using 5GS credentials for Non-seamless WLAN offload are further defined in TS 33.501 Annex S. The UE can also connect to a WLAN access network using 5GS credentials by performing the 5GS registration via trusted non-3GPP access procedure defined in TS 23.502, clause 4.12a.2.2. With this procedure, the UE connects to a WLAN access network using 5GS credentials and simultaneously registers in 5GS. However, the architecture defined in Figure 4.2.15-1 enables a UE to connect to a WLAN access network using 5GS credentials but without registration in 5GS.