Section: 6.3.3.2 SMF Provisioning of available UPF(s)
Content: SMF may be locally configured with the information about the available UPFs, e.g. by OA&M system when UPF is instantiated or removed. NOTE 1: UPF information can be updated e.g. by OA&M system any time after the initial provisioning, or UPF itself updates its information to the SMF any time after the node level interaction is established. The UPF selection functionality in the SMF may optionally utilize the NRF to discover UPF instance(s). In this case, the SMF issues a request to the NRF that may include following parameters: DNN, S-NSSAI, SMF Area Identity, the requested functionalities and capabilities (e.g. ATSSS steering capabilities, functionality associated with high data rate low latency service etc.). In its answer, the NRF provides the NF profile(s) that include(s) the IP address(es) or the FQDN of the N4 interface of corresponding UPF instance(s) to the SMF. UPFs may be associated with an SMF Area Identity in the NRF. This allows limiting the SMF provisioning of UPF(s) using NRF to those UPF(s) associated with a certain SMF Area Identity. This can e.g. be used in the case that an SMF is only allowed to control UPF(s) configured in NRF as belonging to a certain SMF Area Identity. The NRF may be configured by OAM with information on the available UPF(s) or the UPF instance(s) may register its/their NF profile(s) in the NRF. This is further defined in clause 4.17 of TS 23.502[ Procedures for the 5G System (5GS) ]  [3].