PDU Session Establishment Call Flow
This section describes the PDU session establishment procedure involving a request for Always-on PDU session initiation in the Create Session Request.
The following figure illustrates the PDU Session Establishment call flow.

Step | Description |
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1 |
If the UE requests to establish an always-on PDU session, the UE includes an "Always-on PDU Session Requested" IE in the PDU Session Establishment Request message. |
2 |
The SMF checks the DNN profile to determine whether the always-on support is enabled. |
3 |
The SMF includes an "Always-on PDU Session Indication" IE in the PDU Session Establishment Accept message if one of the following is true:
|
4 |
The SMF does not include an "Always-on PDU Session Indication" only when both these conditions are true:
|