PV4V6 Key: defaultSessionType Key: pduSessionTypes Member Key: sessionAmbr Member Key: sscModes Key: ims.lab Key: dnnConfigurations Member Key: singleNssai Object Member Key: sst Number value: Key: sst Key: singleNssai Figure 7.14 - Packet Capture: UDM to SMF subscription fetch response The SMF to AMF communication as is seen on the wire is depicted next. It contains an acknowledgment of the session created and mapped to a unique subscriber context with the IMSI details, as shown in the following figure: IMS 5G PDU session establishment HyperText Transfer Protocol 2 Stream: HEADERS, Stream ID: 1, Length 106, 201 Created Length: 106 Type: HEADERS (1) Flags: 0x04 = Reserved: 0x0 .000 0000 0000 0000 0000 0000 0000 0001 = Stream Identifier: 1 [Pad Length: 0] Header Block Fragment: 3fe11f4e8210035f8b1d75d0620d263d4c7441ea6eb89d29.. [Header Length: 215] [Header Count: 6] Header table size update > Header: :status: 201 Created Header: content-type: application/json Header: location: http://10.193.50.177:8090/nsmf-pdusession/v1/sm-contexts/imsi-310310140000337:1 > Header: content-length: 108 Header: date: Thu, 04 Jun 2020 22:26:30 GMT Figure 7.15 - Packet Capture: SMF to AMF SM Created message The following shows the IMS 5G PDU attach call flow (continued from earlier): gNB/RAN PCSCF NRF Discovery for PCFs PCF Policy Create Request 201 Created PCF Policy Update Request 2000K NRF Discovery for CHFs CHF charging Create Req 201 Created Figure 7.16 - IMS PDU attach procedure - part 2 Packet Core Procedures The subsequent details of the IMS PDU session establishment procedure are listed next via Steps 10 to 16: Step 10: The SMF sends HTTP GET request /nnrf-disc/vl/nf-instances?dnr = ims&requester-nf-type=SMF&target-nf-type=PCF = for PCF instances, and the NRF responds with 200 OK with the service instance ID, API versions, NF (Network Function) service status, and IPv4 addresses. Step 11: The SMF initiates the Npcf_SMPolicy Control_Create request by including SmPolicy ContextData, which contains SUPI, GPSI, PDU session ID, RA