UPF Selection Algorithm
The SMF determines the UPF node based on an algorithm.
The following figure depicts the UPF node selection workflow.

The SMF lists the UPF nodes based on the priority assigned to the node. When there are multiple nodes with the same priority value, then the SMF selects a UPF experiencing the lowest level of load. The load parameter is applied only for UPFs that have the same priority.
When load is not available as a selection criteria, then SMF selects a random UPF when there are multiple UPFs with the same priority.
The SMF stores UPF order list based on priority. When a failure occurs, the SMF selects the next entry in the list based on failure handling template (FHT) configuration.
If priority is not available as a selection criteria and load is available as a selection criteria, then SMF selects least loaded UPF from the list of selected UPFs.
Important | The SMF performs UPF selection only during initial call establishment. In 2021.01 and earlier releases, the support for UPF reselection during HO does not exist. |