UE Registration with Encryption/Integrity Protection Call Flow
The section describes the UE registration procedure with encryption/integrity protection call flow.

Step |
Description |
---|---|
1 |
UE Registration with Encryption/Integrity Protection UE sends registration request to gNB. |
2 |
gNB sends Initial UE Registration Request to AMF. |
3 |
AMF sends UE Authentication (SUCI) to AUSF. |
4 |
AUSF sends UE Authentication Response with Rand, Autn, Kseaf and Hxres information to AUSF. |
5 |
AMF sends DL Nas Transport with N1 Authentication request with Rand and Autn to gNB. |
6, 7 |
gNB sends N1 authentication request to UE and receives N1 Authentication Response from it. |
8 |
gNB sends UL Nas Transport message N1 Authentication Response:Xres* to AMF. |
9, 10 |
AMF derives HXres* from HXres and compares Xres* with Hres*. It sends Nausf suthentication Confirm to AUSF and receives response with SUPI from it. |
11 |
AMF derives Kamf, Kgnb, Knas-int and Knas-enc. It sends DL Nas Transport (N1 Security mode command:Neg Algo,KSI) to gNB. |
12 |
gNB sends N1 Security mode command to UE. |
13 |
UE sends N1 Security Mode Complete to gNB. |
14 |
gNB sends UL Nas Transport (N1 Security Mode complete) to AMF. |
15, 16 |
AMF sends Registration Request to UDM and receives Registration Success from it. |
17, 18 |
AMF sends Subscription Request to UDM and receives Subscription Confirm from it. |
19, 20 |
AMF sends Slice Info Request to NSSF and receives Slice Info Response from it. |
21, 22 |
AMF sends Policy Control Create to PCF and receives Policy Control Create Response from it. |
23, 24 |
AMF sends Initial Context Setup request (kgnb) to gNB and receives response from it. |
25, 26 |
AMF sends DL Nas Transport (Registration Accept) message to gNB. gNB forwards it to UE. |
27, 28 |
UE sends Registration Accept to gNB. gNB forwards this message in UL Nas Transport to AMF. |
29, 30 |
UE sends PDU Session Estblishment Request message to gNB. gNB forwards this message in UL Nas Transport to AMF. |
31, 32 |
AMF sends SM context Create Request message to SMF and receives response from it. |
33 |
SMF sends N1N2 Message Transfer message to AMF. |
34 |
AMF sends PDU Session Resource setup request (PDU session Estb Accept) to gNB. |
35, 36 |
gNB sends PDU Session Resource setup request to UE and receives PDU Session resource setup response from it. |
37, 38 |
AMF sends SM Context Update Request to SMF and receives response from it. |