â–€ How the Serving Gateway Works
â–„ Cisco ASR 5000 Series Product Overview
Figure 160. 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 85. Subscriber-initiated Detach Call Flow Description
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.
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.
The S-GW sends a Delete Bearer Request (TEID) message to the P-GW.
The P-GW acknowledges with a Delete Bearer Response (TEID) message.
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.
The S-GW acknowledges with a Delete Bearer Response (TEID) message.
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.
The MME releases the S1-MME signalling connection for the UE by sending an S1 Release command to the eNodeB with
Cause = Detach.