3GPP 24.501 v20.0.0 — the document's own text

6.2.3 PDU session management

Taught in 6. Getting on the network, and getting a connection through it (CT1 — the group that writes what your phone says, in depth), 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).

The SMF is responsible for the session management functions to provide the PDU connectivity service to the UE via the 5GSM signalling between UE and SMF. The session management procedures includes:

the UE-requested PDU session establishment procedure;
the PDU session authentication and authorization procedure;
the UE-requested PDU session modification procedure;
the network-requested PDU session modification procedure;
the UE-requested PDU session release procedure; and
the network-requested PDU session release procedure.

A UE may establish multiple PDU sessions, to the same data network or to different data networks, via 3GPP access and via non-3GPP access at the same time. It is not required for a UE to initiate the PDU session release procedure to release a PDU session associated with another access, if any, due to the reason that the UE initiates the registration procedure or PDU session establishment procedure over the current access.

NOTE: PDU session is managed independently between 3GPP access and non-3GPP access.

The session management messages between UE and SMF are transferred via AMF as specified in clause 8.3.