UE Registration with Encryption/Integrity Protection Call Flow

The section describes the UE registration procedure with encryption/integrity protection call flow.

UE Registration with Encryption/Integrity Protection Call Flow
UE Registration with Encryption/Integrity Protection Call Flow Description

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.