Section: E.3 Delegated PCF discovery in the Roaming scenario
Content: Figure E.3: Delegated Discovery of PCF in the Home Routed Scenario 1. The AMF sends Nnrf_NFDiscovery Request to the V-NRF in order to discover a PCF in HPLMN. The AMF may indicate the maximum number of H-PCF instances to be returned by the NRF. 2. The NRF in VPLMN and NRF in HPLMN interact using the Nnrf_NFDiscovery service. See step 2 in clause 4.17.5. 3. The AMF gets Nnrf_NFDiscovery service response with one or more profile(s) of PCF(s) in HPLMN. 4. The AMF selects a PCF instance in HPLMN. 5. The AMF builds a Npcf_UEPolicyControl Request that contains the H-PCF ID in the body of the request. If the AMF supports delegated PCF discovery and is configured to apply it, the AMF forwards the Npcf_UEPolicyControl Request to the selected SCP in VPLMN.together with Discovery & Selection parameter set to V-PCF instance ID. 6. The SCP in VPLMN selects the corresponding (V-)PCF instance for UE policy association based on Discovery & Selection parameter received from the AMF. 7. The SCP in VPLMN forwards the Npcf_UEPolicyControl Request to the selected PCF instance in VPLMN. 8. If the V-PCF does not support delegated PCF discovery or is not configured to apply it (Case A), the V-PCF sends Npcf_UEPolicyControl Request to the selected PCF instance. Otherwise (Case B), the V-PCF sends the Npcf_UEPolicyControl Request to a SCP in VPLMN but adds Discovery & Selection parameter set to H-PCF ID. 9. The SCP in VPLMN sends an Npcf_UEPolicyControl Request to the selected PCF instance in HPLMN indicated in step 8.