PDU Session Release Call Flow

The PDU Session Release procedure is used to release all the resources associated with a PDU session, including:

  • The IP address/prefixes allocated for an IP-based PDU session

  • Any UPF resource that was used by the PDU session.

  • Any access resource that was used by the PDU session.

The SMF notifies any entity associated with the PDU session: PCF, Data Network (DN) (for example, when DN authorization has taken place at PDU session establishment), and so on.

There are different ways to initiate the PDU session release. It can be from UE, network, AMF, or RAN.