Cisco ASR 5000 Series - Page 568

PDN Gateway Overview
▀ How the PDN Gateway Works
▄ Cisco ASR 5000 Series Product Overview
OL-22938-02
Figure 142. Subscriber-initiated Detach Call Flow
Delete
Bearer Rsp
PCRF
Interactions
Delete
Bearer Rsp
Delete
Bearer Req
eNodeB MME S-GWUE P-GW PCRF HSS
1
2
Detach Request
5
Delete
Bearer Req
3
4
6
Detach Response
Signaling
Connection Rel
8
7
Table 78. Subscriber-initiated Detach Call Flow Description
Step
Description
1
The UE sends NAS message Detach Request (GUTI, Switch Off) to the MME. Switch Off indicates whether detach is due
to a switch off situation or not.
2
The active EPS Bearers in the S-GW regarding this particular UE are deactivated by the MME sending a Delete Bearer
Request (TEID) message to the S-GW.
3
The S-GW sends a Delete Bearer Request (TEID) message to the P-GW.
4
The P-GW acknowledges with a Delete Bearer Response (TEID) message.
5
The P-GW may interact with the PCRF to indicate to the PCRF that EPS Bearer is released if PCRF is applied in the
network.
6
The S-GW acknowledges with a Delete Bearer Response (TEID) message.
7
If Switch Off indicates that the detach is not due to a switch off situation, the MME sends a Detach Accept message to the
UE.
8
The MME releases the S1-MME signalling connection for the UE by sending an S1 Release command to the eNodeB with
Cause = Detach.