Section: 4.2.8 Support of non-3GPP access 4.2.8.1A General Concepts to support Wireline Access
Content: Wireline 5G Access Network (W-5GAN) shall be connected to the 5G Core Network via a Wireline Access Gateway Function (W-AGF). The W-AGF interfaces the 5G Core Network CP and UP functions via N2 and N3 interfaces, respectively. For the scenario of 5G-RG connected via NG RAN the specification for UE defined in this TS, TS 23.502[ Procedures for the 5G System (5GS) ]  [3] and TS 23.503[ Policy and charging control framework for the 5G System (5GS); Stage 2 ]  [45] are applicable as defined for UE connected to 5GC via NG RAN unless differently specified in this TS and in TS 23.316[ Wireless and wireline convergence access support for the 5G System  (5GS) ]  [84]. When a 5G-RG is connected via a NG-RAN and via a W-5GAN, multiple N1 instances shall exist for the 5G-RG i.e. there shall be one N1 instance over NG-RAN and one N1 instance over W-5GAN. A 5G-RG simultaneously connected to the same 5G Core Network of a PLMN over a 3GPP access and a W-5GAN access shall be served by a single AMF in this 5G Core Network. 5G-RG shall maintain the NAS signalling connection with the AMF over the W-5GAN after all the PDU Sessions for the 5G-RG over that access have been released or handed over to 3GPP access. The 5G-RG connected to 5GC via NG-RAN is specified in TS 23.316[ Wireless and wireline convergence access support for the 5G System  (5GS) ]  [84]. For the scenario of FN-RG, which is not 5G capable, connected via W-5GAN to 5GC, the W-AGF provides the N1 interface to AMF on behalf of the FN-RG. An UE connected to a 5G-RG or FN-RG can access to the 5GC via the N3IWF or via the TNGF where the combination of 5G-RG/FN-RG, W-AGF and UPF serving the 5G-RG or FN-RG is acting respectively as Untrusted Non-3GPP access network or as a Trusted Non-3GPP access network defined in clause 4.2.8.2; for example a UE is connecting to 5G-RG by means of WLAN radio access and connected to 5GC via N3IWF. The detailed description is specified in TS 23.316[ Wireless and wireline convergence access support for the 5G System  (5GS) ]  [84]. The roaming architecture for 5G-BRG, FN-BRG, 5G-CRG and FN-CRG with the W-5GAN is not specified in this Release. The Home Routed roaming scenario is supported for 5G-RG connected via NG RAN, while Local Breakout scenario is not supported. 5G Multi-Operator Core Network (5G MOCN) is supported for 5G-RG connected via NG RAN as defined in clause 5.18