Session Create, Update, and Terminate Call Flow

This section describes the call flow to create, update, or terminate a session.
Session Creation, Update, and Termination Call Flow
Session Creation, Update, and Termination Call Flow Description

Step

Description

1

The SMF sends a Policy Control Create request to the PCF REST endpoint.

2

The PCF REST endpoint forwards the request to the PCF Engine.

3

The PCF Engine sends a Create Session request to Session DB/CDL.

4

The Session DB/CDL sends an acknowledgement to the PCF Engine for the Create Session request.

5

The PCF performs a binding or tagging the database and sends it to the Binding DB.

6

The PCF confirms that the binding or tagging of the database is complete by sending an acknowledgement to the PCF Engine.

7

The PCF Engine sends Policy response to the PCF REST endpoint.

8

The PCF REST endpoint creates a response and sends it to the SMF.

9

A new session is created on PCRF. The P-GW sends Gx CCR request to the PCRF LB.

10

The PCRF LB sends the Diameter request to the PCRF QNS.

11

The PCRF QNS creates a session in the session database and sends it to PCRF.

12

The session database sends an acknowledgement to the PCRF indicating that the session is created.

13

The PCRF QNS performs the binding and notifies the PCRF.

14

The PCRF sends an acknowledgement to the PCRF QNS indicating that the binding is created.

15

The PCRF QNS sends Diameter response to the PCRF LB.

16

The PCRF LB sends Gx CCA request to the P-GW.

17

The P-CSCF sends Rx AAR request to the PCF Diameter endpoint.

18

The PCF Diameter endpoint checks if the session exists on PCF.

19

If the PCRF BindingDB lookup is enabled, the PCF Diameter endpoint checks whether the session exists on PCRF.

20

In the existing session of the PCRF SkDB instance with lookup enabled, the PCF Diameter endpoint sends the Rx AAR request over the gRPC interface to the PCRF QNS.

21

The PCRF QNS processes the AAR request.

22

The PCRF QNS binds or tags the database and sends an acknowledgement to PCRF.

23

The PCRF acknowledges the binding or tagging of the database and notifies the PCRF QNS.

24

The PCRF QNS sends Create Session request to the PCRF.

25

The PCRF sends an acknowledgement for the request to the PCRF QNS.

26

The PCRF QNS sends Rx AAR request to the PCRF QNS.

27

The PCRF QNS sends Diameter request to the PCRF LB.

28

The PCRF LB sends Gx RAR request to the P-GW.

29

The P-GW sends the Gx RAA response to PCRF LB.

30

In the existing session of PCF, the PCF Diameter endpoint sends Diameter request to the PCF REST endpoint.

31

The PCF Engine processes the AAR request.

32

The PCF Engine sends a Create Session request to Session DB/CDL.

33

The Session DB/CDL sends an acknowledgement to PCF Engine.

34

PCF sends a Create New Binding/Tag request to the Binding DB.

35

The Binding DB sends an acknowledgement to PCF.

36

The PCF Engine sends Notification request to the PCF REST endpoint.

37

The PCF REST endpoint sends a Diameter response request to the PCF Diameter endpoint.

38

The PCF Diameter endpoint sends Policy Notification Request to the P-CSCF.

39

The P-CSCF sends the Policy Notification response to the PCF Diameter endpoint.

40

The PCF Diameter endpoint sends the Rx AAA request to the P-CSCF.