nt GET message to the UDM. 26. The UDM responds with Access and Mobility Subscription Data and SMF selection Subscription Data. 27. The AMF sends a Subscribe to change notifications message to the UDM. 28. The UDM sends an acknowledgment for the subscribe to change notifications message. 29. The AMF sends a DL NAS transport message to the gNB. 30. The gNB sends the NAS message requesting the IMEI to the UE. 31. The UE sends the IMEI using the UL information Transport Message to the gNB. 32. The gNB sends the UL NAS transport message containing the IMEI to the AMF. 33. The AMF uses the IMEI for the equipment identity check procedure with the Equipment Identity Repository (EIR). 34. The EIR acknowledges the request: 5G Standalone Networks UE Performs Registration: AM Policy Association (4 of 5) AM PCF AM Policy Association Data Repository Query (SUPI, Access & MM Policies) Ack (Access & MM Policies) Data Repository Subscribe (SUPI, Access & MM Policy Changes) Subscription Ack Ack (Policies, Triggers) DL NAS Transport NAS: Registration Accept DL Info Transport UL Info Tansport NAS: Registration Complete UL NAS Xport Integrity Protected Msg Int. Protect & Ciphered Figure 11.7 - UE registration - part 4: AM policy association 35. The AMF may then send AM Policy Association Request to the Policy Control Function (PCF). 36. The PCF sends a Data Repository query to the UDR using SUPI as the key to retrieve Access and MM Policies. 37. The UDR sends an acknowledgment to the PCF and returns the requested Access and MM policies. 38. The AM PCF then sends a Data Repository Subscribe message to the UDR, requesting notifications for any policy changes. 39. The UDR acknowledges this. 40. The PCF then acknowledges the completed AM policy association to the AMF and sends it to the policies and triggers it has received from the UDR. 41. The AMF sends a NAS Registration Accept message to the gNB to be sent to the UE. 42. The gNB transfers the NAS message to the UE. 43. The UE responds with a UL Info Transport message carrying the NA