hnologies. This is how Wi-Fi and New Radio (5G radio) can complement each other and do not need to be treated as competing technologies. Wi-Fi attach IKE_SA_AUTH Create_Session Request (GTPv2) UDM Registration Request 201 Created UDM Subscription Fetch Request 200 OK UDM Subscription Notification Request 201 Created Figure 7.29 - Wi-Fi attach - part 1 We will now go over the Wi-Fi attach procedure: Step 1: The UE sends the IKE SA AUTH exchange message to ePDG (IWF-interworking function) to create the IPSec tunnel. Step 2: The UE sends the IKE_SA_AUTH exchange message to the SMF+PGW-C as a GTP Create Session request by including the P-CSCF IPv4 or IPv6 request and DNS IPv4 or IPv6 container identifier in APCO IE options. The ePDG checks the UE capability information to determine whether it is supposed to anchor to a 5G SMF or a 4G PGW. Step 3: The SMF+PGW-C extracts and saves the PDU session ID that the UE sent in the APCO IE option and sends a UDM registration HTTP PUT request (/ /nudm-uecm/v1/imsi-12 xxxxxxxx37/ registrations/smf-registrations/1) and sends the PDU session ID, DNN, and NSSAI info. Step 4: For the successful transaction, UDM responds with 201 Created. Step 5: The SMF fetches the session management subscription data for the corresponding SUPI, DNN, and S-NSSAI with httpGET/nudm-sdm/v2/imsi-123123111111111/ - sm-data?dnn=imslab&plmn-id=2%7 - D&sing!e-nssai=%7%7D &supported- features=0 Packet Core Procedures Step 6: For the successful transaction, UDM responds with 200 OK and sends the DNN configurations - "5gQos profile: 5qi", "arp: SessAmbr" values, iwkEpsind, and SO on. Step 7: The SMF sends an HTTP POST subscription notification request to UDM for POST/nudm- sdm/v2/imsi-1 123123xxxxxx/sdm-subs Step 8: For the successful transaction, UDM responds with 201 Created. NRF Discovery for PCFs PCF Policy Create Request 201 Created PCF Policy Update Request 2000K Figure 7.30 - Wi-Fi attach - part 2 Step 9: The SMF sends an HTTP GET request (/nnrf-disc/vl/nf-instances?dnn=ims. lab&requester-nf-type=SMF = &