5G INTERFACES,NODES AND REFERENCE POINTS

5G is fifth generation technology and it will have latency as low as 1ms and speed upto 20Gbps.

In this article we are discussing about interfaces and nodes added in 5G network.

Nodes:

- Authentication Server Function (AUSF)

- Access and Mobility Management Function (AMF)

- Data Network (DN), e.g. operator services, Internet access or 3rd party services

- Unstructured Data Storage Function (UDSF)

- Network Exposure Function (NEF)

- Network Repository Function (NRF)

- Network Slice Selection Function (NSSF)

- Policy Control Function (PCF)

- Session Management Function (SMF)

- Unified Data Management (UDM)

- Unified Data Repository (UDR)

- User Plane Function (UPF)

- UE radio Capability Management Function (UCMF)

- Application Function (AF)

- User Equipment (UE)

- (Radio) Access Network ((R)AN)

- 5G-Equipment Identity Register (5G-EIR)

- Network Data Analytics Function (NWDAF)

- CHarging Function (CHF)

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.

N5:         Reference point between the PCF and an AF.

N6:         Reference point between the UPF and a Data Network.

N7:         Reference point between the SMF and the PCF.

N8:         Reference point between the UDM and the AMF.

N9:         Reference point between two UPFs.

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.

N29: Reference point between NEF and SMF.

N29i: Reference point between I-NEF and SMF in the VPLMN.

N31: Reference point between the NSSF in the visited network and the NSSF in the home network.

N32: Reference point between SEPP in the visited network and the SEPP in the home network.

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.

N40: Reference point between SMF and the CHF.

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.

N58: Reference point between AF and the NEF.

N51: Reference point between NEF and the AMF.

N51i: Reference point between I-NEF and the AMF in the VPLMN.

N52: Reference point between the I-NEF and the NEF.

Service-based Interface:

Namf: Service-based interface exhibited by AMF.

Nsmf: Service-based interface exhibited by SMF.

Nnef: Service-based interface exhibited by NEF.

Npcf: Service-based interface exhibited by PCF.

Nudm: Service-based interface exhibited by UDM.

Naf: Service-based interface exhibited by AF.

Nnrf: Service-based interface exhibited by NRF.

Nnssf: Service-based interface exhibited by NSSF.

Nausf: Service-based interface exhibited by AUSF.

Nudr: Service-based interface exhibited by UDR.

Nudsf: Service-based interface exhibited by UDSF.

N5g-eir: Service-based interface exhibited by 5G-EIR.

Nnwdaf: Service-based interface exhibited by NWDAF.

Ni-nef: Service-based interface exhibited by I-NEF.

Nchf: Service-based interface exhibited by CHF.

Nucmf: Service-based interface exhibited by UCMF.

For more information related to system architecture please refer 23.501 3gpp spec.