Hi Dhinesh,
From RFC-4006 Section 5.4 , It states that "When the end user terminates the service session, or when the graceful service termination described in section 5.6 takes place, the Diameter credit-control client MUST send a final Credit-Control-Request message to the credit-control server. The CC-Request-Type AVP is set to the value TERMINATION_REQUEST. The Service-Context-Id AVP indicates the service specific document applicable to the request."
Also one more scenario If the user logs off during an ongoing credit-control session, or if some other reason causes the user to become logged off (e.g., final-unit indication causes user logoff according to local policy), the service element, according to application specific policy, may send a Session-Termination-Request (STR) to the home Diameter AAA server as usual [DIAMBASE]. Figure 4 illustrates the case when the final-unit indication causes user logoff upon consumption of the final grantedunits and the generation of STR.
Service Element AAA Server CC Server
End User (CC Client)
| Service Delivery | | |
|<----------------->| | |
| : | | |
| : | | |
| : | | |
| | | |
| | CCR(Update,Used-Units) |
| |------------------->| CCR(Update,Used-Units)
| | |------------------->|
| | CCA(Final-Unit, Terminate)
| CCA(Final-Unit, Terminate)|<-------------------|
| |<-------------------| |
| : | | |
| : | | |
| Disconnect user | | |
|<------------------| CCR(Termination,Used-Units) |
| |------------------->| CCR(Term.,Used-Units)
| | |------------------->|
| | | CCA |
| | CCA |<-------------------|
| |<-------------------| |
| | STR | |
| |------------------->| |
| | STA | |
| |<-------------------| |
Figure 1: User disconnected due to exhausted account
I request you to please refer the diagram from RFC-4006 from Section 5.4 , here I am not able to do proper identation.
Basically it is always Diameter Credit Control Client which may be GGSN or P-GW.
Thanks