Section: 4.2.7 Reference points
Content: The 5G System Architecture contains the following reference points: N1: Reference point between the UE and the AMF. N2: Reference point between the (R)AN and the AMF. N3: Reference point between the (R)AN and the UPF. N4: Reference point between the SMF and the UPF. N6: Reference point between the UPF and a Data Network. N9: Reference point between two UPFs. The following reference points show the interactions that exist between the NF services in the NFs. These reference points are realized by corresponding NF service-based interfaces and by specifying the identified consumer and producer NF service as well as their interaction in order to realize a particular system procedure. N5: Reference point between the PCF and an AF or TSN AF. N7: Reference point between the SMF and the PCF. N8: Reference point between the UDM and the AMF. N10: Reference point between the UDM and the SMF. N11: Reference point between the AMF and the SMF. N12: Reference point between AMF and AUSF. N13: Reference point between the UDM and Authentication Server function the AUSF. N14: Reference point between two AMFs. N15: Reference point between the PCF and the AMF in the case of non-roaming scenario, PCF in the visited network and AMF in the case of roaming scenario. N16: Reference point between two SMFs, (in roaming case between SMF in the visited network and the SMF in the home network). N16a: Reference point between SMF and I-SMF. N17: Reference point between AMF and 5G-EIR. N18: Reference point between any NF and UDSF. N19: Reference point between two PSA UPFs for 5G LAN-type service. N22: Reference point between AMF and NSSF. N23: Reference point between PCF and NWDAF. N24: Reference point between the PCF in the visited network and the PCF in the home network. N27: Reference point between NRF in the visited network and the NRF in the home network. N28: Reference point between PCF and CHF. N29: Reference point between NEF and SMF. N30: Reference point between PCF and NEF. NOTE 1: The functionality of N28 and N29 and N30 reference points are defined in TS 23.503[ Policy and charging control framework for the 5G System (5GS); Stage 2 ]  [45]. N31: Reference point between the NSSF in the visited network and the NSSF in the home network. NOTE 2: In some cases, a couple of NFs may need to be associated with each other to serve a UE. N32: Reference point between a SEPP in one PLMN or SNPN and a SEPP in another PLMN or SNPN; or between a SEPP in a SNPN and a SEPP in a CH/DCS, where the CH/DCS contains a UDM/AUSF. NOTE 3: The functionality of N32 reference point is defined in TS 33.501[ Security architecture and procedures for 5G System ]  [29]. N33: Reference point between NEF and AF. N34: Reference point between NSSF and NWDAF. N35: Reference point between UDM and UDR. N36: Reference point between PCF and UDR. N37: Reference point between NEF and UDR. N38: Reference point between I-SMFs and between V-SMFs. N40: Reference point between SMF and the CHF. N41: Reference point between AMF and CHF in HPLMN. N42: Reference point between AMF and CHF in VPLMN. NOTE 4: The functionality of N40, N41 and N42 reference points are defined in TS 32.240[ Telecommunication management; Charging management; Charging architecture and principles ]  [41]. N43: Reference point between PCFs. NOTE 5: The functionality of N43 reference point is defined in TS 23.503[ Policy and charging control framework for the 5G System (5GS); Stage 2 ]  [45]. NOTE 6: The reference points from N44 up to and including N49 are reserved for allocation and definition in TS 32.240[ Telecommunication management; Charging management; Charging architecture and principles ]  [41]. N50: Reference point between AMF and the CBCF. N51: Reference point between AMF and NEF. N52: Reference point between NEF and UDM. N55: Reference point between AMF and the UCMF. N56: Reference point between NEF and the UCMF. N57: Reference point between AF and the UCMF. NOTE 7: The Public Warning System functionality of N50 reference point is defined in TS 23.041[ Technical realization of Cell Broadcast Service (CBS) ]  [46]. N58: Reference point between AMF and the NSSAAF. N59: Reference point between UDM and the NSSAAF. N60: Reference point between AUSF and NSWOF. NOTE 8: The functionality of N60 reference point is defined in TS 33.501[ Security architecture and procedures for 5G System ]  [29]. N80: Reference point between AMF and NSACF. N81: Reference point between SMF and NSACF. N82: Reference point between NSACF and NEF. N83: Reference point between AUSF and NSSAAF. N84: Reference point between TSCTSF and PCF. N85: Reference point between TSCTSF and NEF. N86: Reference point between TSCTSF and AF. N87: Reference point between TSCTSF and UDM. N88: Reference point between SMF and EASDF. N89: Reference point between TSCTSF and AMF. N96: Reference point between TSCTSF and NRF. N97: Reference point between two NSACFs in different PLMNs. N99: Reference point between two NSACFs within the same PLMN. NOTE 9: The reference points from N90 up to and including N95 are reserved for allocation and definition in TS 23.503[ Policy and charging control framework for the 5G System (5GS); Stage 2 ]  [45]. NOTE 10: The reference points from N100 up to and including N109 are reserved for allocation and definition in TS 32.240[ Telecommunication management; Charging management; Charging architecture and principles ]  [41]. The reference points to support SMS over NAS are listed in clause 4.4.2.2. The reference points to support Location Services are listed in TS 23.273[ 5G System (5GS) Location Services (LCS); Stage 2 ]  [87]. The reference points to support SBA in IMS (N5, N70 and N71) are described in TS 23.228[ IP Multimedia Subsystem (IMS); Stage 2 ]  [15]. The reference points to support AKMA (N61, N62 and N63) are described in TS 33.535[ Authentication and Key Management for Applications (AKMA) based on 3GPP credentials in the 5G System (5GS) ]  [124]. The reference points to support 5G ProSe are described in TS 23.304[ Proximity based Services (ProSe) in the 5G System (5GS) ]  [128]. The reference points to support 5G multicast-broadcast services are described in TS 23.247[ Architectural enhancements for 5G multicast-broadcast services ]  [129]. The reference points to Support Uncrewed Aerial Systems (UAS) connectivity, identification and tracking are described in TS 23.256[ Support of Uncrewed Aerial Systems (UAS) connectivity, identification and tracking; Stage 2 ]  [136]. The reference points to support SBA in GBA and GBA push (N65, N66, N67 and N68) are described in TS 33.220[ Generic Authentication Architecture (GAA); Generic Bootstrapping Architecture (GBA) ]  [140] and TS 33.223[ Generic Authentication Architecture (GAA); Generic Bootstrapping Architecture (GBA) Push function ]  [141]. The reference points to support SMS delivery using SBA are described in TS 23.540[ 5G System: Technical realization of Service Based Short Message Service; Stage 2 ]  [142]. The reference points to support Ranging based services and Sidelink Positioning are described in TS 23.586[ Architectural Enhancements to support Ranging based services and Sidelink Positioning ]  [180].