Moving pdu sessions between networks

A wireless transmit/receive unit (WTRU) comprising:

• a transceiver;
• and
• a processor communicatively coupled with the transceiver and adapted to enable the WTRU to transition from a first wireless network (NW1) to a second wireless network (NW2) having different session management protocols by configuring the transceiver and the processor to:
• receive, from the NW1, a slice specific non-access stratum (NAS) ingress identifier;
• initiate a protocol data unit (PDU) session establishment procedure with the NW1 to establish a first PDU session based on a PDU session establishment request for communication with a slice specific NAS ingress function associated with the slice specific NAS ingress identifier;
• receive, from the NW1, a PDU session establishment accept message in response to the PDU session establishment request;
• and
• register with the NW2 and perform a PDU session establishment procedure with the NW2 to establish a third PDU session for exchanging control plane messages with the slice specific NAS ingress function associated with the slice specific NAS ingress identifier.

A method for a wireless transmit/receive unit (WTRU) to transition from a first wireless network (NW1) to a second wireless network (NW2) having different session management protocols, the method comprising:

• receiving route selection policy (RSP) rules and a list of network slices the WTRU is permitted to access via the NW1 and information on which of the network slices are accessible via the NW2 and support non-access stratum (NAS) signaling via an application layer;
• receiving a first protocol data unit (PDU) from an application for transmission and using a first RSP rule to determine a first single network slice selection assistance information (S-NSSAI) and data network name (DNN) combination detected as accessible via the NW1 and the NW2 to transmit the first PDU via a PDU session with the first S-NSSAI/DNN combination;
• triggering a second RSP rule upon attempting to send a NAS session management PDU session establishment request to establish the PDU session, wherein the second RSP rule determines a second S-NSSAI/DNN combination;
• performing a first PDU session establishment procedure indicating the second S-NSSAI/DNN combination, wherein a PDU session establishment request is sent via a signal radio bearer (SRB), resulting in a first PDU session used to exchange NAS signaling via the application layer;
• and
• performing a second PDU session establishment procedure indicating the first S-NSSAI/DNN combination, wherein a PDU session establishment request message for the second PDU session establishment procedure is sent via the first PDU session using data radio bearers (DRBs) and used to communicate application layer data.