Feature Description
The always-on Protocol Data Unit (PDU) session means that the user plane is always active. Applications such as the IP Multimedia Subsystem (IMS) requires an always-on PDU session.
The UE requests the establishment of a PDU session as an always-on PDU session based on the request indication of the upper layers. It is the network that decides whether to establish a PDU session as an always-on PDU session.