hSMF Create Session Procedure

This section provides details about the create session procedure for hSMF.

hSMF Create Session Call Flow
hSMF Create Session Call Flow Description

Step

Description

1

The hSMF receives a request to create a PDU Session from the vSMF. The request has a JSON part and also a binary part, which has the list of IEs that the vSMF did not process, or could not process.

2

The hSMF retrieves the subscription data for the UE from the UDM.

3

If based on the subscription data, the session can be established, then the SMF subscribes to changes for the subscription data to the UDM.

4

The hSMF creates a policy association with the PCF. The PCF can either be one that has been selected by the AMF and signaled to the hSMF, or an NRF based or policy based selection on the hSMF.

5

A Charging Data association is created with the CHF.

6

Using the CN tunnel information provided by the vSMF in step 1, the hSMF creates CN tunnels on the hUPF. The hUPF responds with the CN tunnel information on the hUPF.

7

The hSMF registers with the UDM for any notifications for the UE in this DNN.

8

The hSMF responds to the request from the vSMF, with the CN tunnel information of the hUPF, and N1 information elements that need to be sent to the UE. If the UE has requested always-on session, and this is acceptable to the hSMF, then it's indicated to the vSMF in the response.

9 If IPV6 router advertisements are required to be transmitted, then the hSMF requests the UPF to perform that task.