Section: 6.1.3.3.2 Synchronization failure recovery in Home Network
Content: Upon receiving an authentication failure message with synchronisation failure (AUTS) from the UE, the SEAF sends an Nausf_UEAuthentication_Authenticate Request message with a "synchronisation failure indication" to the AUSF and the AUSF sends an Nudm_UEAuthentication_Get Request message to the UDM/ARPF, together with the following parameters: - RAND sent to the UE in the preceding Authentication Request, and - AUTS received by the SEAF in the response from the UE to that request, as described in subclause 6.1.3.2.0 and 6.1.3.3.1. An SEAF will not react to unsolicited "synchronisation failure indication" messages from the UE. The SEAF does not send new authentication requests to the UE before having received the response to its Nausf_UEAuthentication_Authenticate Request message with a "synchronisation failure indication" from the AUSF (or before it is timed out). When the UDM/ARPF receives an Nudm_UEAuthentication_Get Request message with a "synchronisation failure indication" it acts as described in TS 33.102[ 3G security; Security architecture ]  [9], clause 6.3.5 where ARPF is mapped to HE/AuC. The UDM/ARPF sends an Nudm_UEAuthentication_Get Response message with a new authentication vector for either EAP-AKA’ or 5G-AKA depending on the authentication method applicable for the user to the AUSF. The AUSF runs a new authentication procedure with the UE according to clauses 6.1.3.1 or 6.1.3.2 depending on the authentication method applicable for the user.