Call Flow
The following figure shows the call flow details and the message exchanges in a 5G core system.

Step |
Description |
---|---|
1 |
The PCF sends SmPolicyUpdateNotify to SMF, and receives an acknowledgment. |
2 |
SMF activates the ADC rule (Predefined rule). |
3 |
SMF maintains the predefined rule for Application ID mapping. |
4 |
SMF sends the N4 Session Modification Request to UPF, and receives a response from UPF. |
5 |
ADC is activated at the UPF. |
6 |
UPF detects the packets matching ADC rule. |
7 |
UPF sends the N4SessionUpdate request to the SMF, and receives a response from the SMF. UPF triggers Application Start. |
8 |
SMF sends the SmPolicyUpdate Request to PCF, and receives an acknowledgment from the PCF. Optionally, the dedicated bearer is created as part of response. |
9 |
PCF sends SmPolicyUpdateNotify to SMF, and receives an acknowledgment from SMF. |
10 |
PCF sends dynamic rule for QCI 80 bearer, and a dedicated bearer is setup. |
11 |
UPF switches the traffic to dedicated bearer. |
12 |
UPF detects stop of traffic on dedicated bearer. |
13 |
UPF sends the N4SessionUpdate request to the SMF, and receives a response from the SMF. UPF triggers Application Stop. |
14 |
SMF sends the SmPolicyUpdate Request to PCF, and receives an acknowledgment from the PCF. Optionally, the dedicated bearer is removed as part of response. |
15 |
PCF sends SmPolicyUpdateNotify to SMF, and receives an acknowledgment from SMF. |
16 |
PCF sends removal of dynamic rule for QCI 80 bearer, and the dedicated bearer is removed. |