Section: 4.2.8.3.1 Overview
Content: The description of the reference points specific for the non-3GPP access: N2, N3, N4, N6: these are defined in clause 4.2. Y1 Reference point between the UE and the untrusted non-3GPP access (e.g. WLAN). This depends on the non-3GPP access technology and is outside the scope of 3GPP. Y2 Reference point between the untrusted non-3GPP access and the N3IWF for the transport of NWu traffic. Y4 Reference point between the 5G-RG and the W-AGF which transports the user plane traffic and the N1 NAS protocol. The definition of this interface is outside the scope of 3GPP. Y5 Reference point between the FN-RG and the W-AGF. The definition of this interface is outside the scope of 3GPP. Yt Reference point between the UE and the TNAP. See e.g. Figure 4.2.8.2.1-2. Yt' Reference point between the N5CW devices and the TWAP. It is defined in clause 4.2.8.5. NWu Reference point between the UE and N3IWF for establishing secure tunnel(s) between the UE and N3IWF so that control-plane and user-plane exchanged between the UE and the 5G Core Network is transferred securely over untrusted non-3GPP access. NWt Reference point between the UE and the TNGF. A secure NWt connection is established over this reference point, as specified in clause 4.12a.2.2 of TS 23.502[ Procedures for the 5G System (5GS) ]  [3]. NAS messages between the UE and the AMF are transferred via this NWt connection. Ta A reference point between the TNAP and the TNGF, which is used to support an AAA interface. Ta requirements are documented in clause 4.2.8.3.2. Tn A reference point between two TNGFs, which is used to facilitate UE mobility between different TNGFs (inter-TNGF mobility). Tn and inter-TNGF mobility are not specified in this Release of the specification.