4 Overview

29.5093GPP5G SystemAuthentication Server ServicesRelease 18Stage 3TS

4.1 Introduction

The Network Function (NF) Authentication Server Function (AUSF) is the network entity in the 5G Core Network (5GC) supporting the following functionalities:

– Authenticate the UE for the requester NF,

– Provide keying material to the requester NF,

– Protect the Steering Information List for the requester NF.

– Protect the UE Parameter Update Data for the requester NF.

Figure 4-1 shows the reference architecture for the AUSF:

Figure 4-1: AUSF in 5G System architecture

This figure represents the AUSF architecture in the Service-based Architecture model. In the reference point model, the interface between the AMF and the AUSF is named N12. In this release, the SEAF function is collocated with the AMF. The AUSF may provide the service to the UDM.

Figure 4-1 illustates PLMN level scenarios, but this architecture is also applicable to the SNPN scenarios, as explained below.

In the case of SNPN, the AUSF provides services e.g. in the following scenarios:

– For an SNPN for which roaming is not supported (see 3GPP TS 23.501 [2], clause 5.30.2.0)

– For the case of UE access to SNPN using credentials from Credentials Holder (see 3GPP TS 23.501 [2], clause 5.30.2.9)

– For the case of Onboarding of UEs for SNPNs (see 3GPP TS 23.501 [2], clause 5.30.2.10)

– For the case of supports the authentication of a 5G ProSe Remote UE (see 3GPP TS 33.503 [26], clause 7.3)