S410. The UE stores the S-NSSAI parameter, the DNN parameter, the SSC mode and the corresponding indication information (if it exists) of the first session.
After S410, optionally, the RAN network element may send a session response (N2 PDU Session Response) to the AMF network element and carry RAN-side tunnel information. For example, the RAN-side tunnel information may include a RAN IP address and a RAN-side tunnel endpoint identifier. The AMF network element sends a session management request to the SMF network element and adds the RAN-side tunnel information to the session management request. The SMF network element initiates a user plane path modification request process, and in this process, the SMF network element sends the RAN-side tunnel information to the UPF network element. The SMF network element returns a session management response to the AMF network element.
In the embodiment shown in