Inter-Network Change Method and Apparatus, and Related Device

An apparatus, comprising:

• at least one memory configured to store instructions;
• and
• at least one processor coupled to the at least one memory and configured to execute the instructions to cause the apparatus to:
• receive, from a terminal and during a registration procedure of the terminal in a first network or after completion of the registration procedure, a packet data network (PDN) connection request requesting a PDN connection, wherein the first network is a 4th generation (4G) mobile communications system;
• determine network slice information about a network slice in a second network, wherein the network slice corresponds to the PDN connection, wherein the second network is a 5th generation (5G) mobile communications system, and wherein the first network and the second network have different core network devices;
• and
• send, to the terminal, a PDN connection response message comprising the network slice information.

An apparatus, comprising:

• at least one memory configured to store instructions;
• and
• at least one processor coupled to the at least one memory and configured to execute the instructions to cause the apparatus to:
• receive, from a terminal, a request message carrying network slice information for the terminal to register with or be handed over to a second network, wherein the network slice information is about a network slice in the second network, wherein the network slice corresponds to a packet data network (PDN) connection of the terminal in a first network, wherein the first network is a 4th generation (4G) mobile communications system, wherein the second network is a 5th generation (5G) mobile communications system, and wherein the first network and the second network have different core network devices;
• and
• send, to the terminal, an accept message carrying allowed network slice information from the second network,
• wherein the allowed network slice information comprises a part or all of the network slice information.

A system, comprising:

• a first apparatus in a first network, wherein the first network is a 4th generation (4G) mobile communications system, and wherein the first apparatus is configured to:
• receive, from a terminal and during a registration procedure of the terminal in the first network or after completion of the registration procedure, a packet data network (PDN) connection request requesting a PDN connection;
• determine network slice information about a network slice in a second network, wherein the network slice corresponds to the PDN connection, wherein the second network is a 5th generation (5G) mobile communications system, and wherein the first network and the second network have different core network devices;
• and
• send, to the terminal, a PDN connection response message comprising the network slice information;
• and
• a second apparatus in the second network and configured to:
• receive, from the terminal, a request message carrying the network slice information for the terminal to register with or be handed over to the second network;
• and
• send, to the terminal, an accept message carrying allowed network slice information from the second network,
• wherein the allowed network slice information comprises a part or all of the network slice information.