Message Priority
The SMF applies the overload protection on the incoming request messages after evaluating the resources' availability to process the request and the message priority. The high priority messages get the lower preference to throttle, and low-priority messages get higher preference. An overloaded NF applies the message prioritization schemes on the incoming messages during an overloaded condition. In such conditions, the NF excludes the messages of the highest priority from the overload protection mechanism.
Once you configure message priority, SMF starts classifying the messages based on their priority. This configuration is optional. If you chose not to use this configuration, SMF applies the overload protection technique without considering the message priority.