User's Manual

Ver.
CHAPTER 4. Message Flow
2600-00FKQFGA2
1.0
Detach by the MME
The figure below shows the message flow of the Detach procedure initiated by the MME.
Figure 19. Detach Procedure by MME
Step
Description
1)~2) The MME detaches the UE implicitly if there is no communication between them for a
long time. In case of the implicit detach, the MME does not transmit the DETACH
REQUEST message to the UE.
If the UE is in the connected state, the MME transmits the DETACH REQUEST message
to the UE to detach it explicitly.
3)~4)
It is the same procedure as step 3) and 4) of ‘Detach Procedure by UE’.
5)~6) When the UE receives the DETACH REQUEST message from the MME in Step 2), the
UE transmits the DETACH ACCEPT message to the MME. The Indoor Pico Cell
transmits this NAS message to the MME.
7) After receiving both of the DETACH ACCEPT message and the Delete Session
Response message, the MME sets the Cause IE value of the UE CONTEXT RELEASE
COMMAND message to ‘Detach’ and transmits this message to the Indoor Pico Cell to
release the S1 connection for the UE.
8)~9)
It is the same procedure as step 8) and 9) of ‘Detach Procedure by UE’.
UE
MME
S-GW
EPC
3) Delete Session Request
6) UPLINK NAS TRANSPORT
(DETACH ACCEPT)
4) Delete Session Response
1) DOWNLINK NAS TRANSPORT
(DETACH REQUEST)
7) UE CONTEXT RELEASE COMMAND
(Detach)
9) UE CONTEXT RELEASE COMPLETE
2) DLInformationTransfer
(DETACH REQUEST)
8) RRCConnectionRelease
5) ULInformationTransfer
(DETACH ACCEPT)
Indoor Pico Cell
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