Handover method, apparatus, and system

A method, performed by a first mobility management network element, the method comprising:

• receiving first request information, wherein the first request information notifies the first mobility management network element to perform path handover on at least one terminal device, the first mobility management network element serves the at least one terminal device, and the at least one terminal device accesses a network through a first device;
• performing path handover on the at least one terminal device based on the first request information, wherein the first request information comprises at least one first request message, and the at least one first request message is in one-to-one correspondence with the at least one terminal device;
• obtaining first device identification information, wherein the first device identification information identifies the first device;
• storing a correspondence between the first device identification information, identification information of the at least one terminal device, identification information of a session management network element of the at least one terminal device, and identification information of a packet data unit (PDU) session;
• and
• sending first session information to the session management network element based on the correspondence, wherein a context of a PDU session of the at least one terminal device is created based on the first session information, wherein the first session information comprises at least one first session message, and the first session message is in one-to-one correspondence with the PDU session of the at least one terminal device.

An apparatus, comprising:

• at least one processor;
• and
• at least one memory coupled to the at least one processor and configured to store programming instructions that, when executed by the at least one processor, cause the apparatus to:
• determine that at least one terminal device is handed over from a first access network device to a second access network device, wherein the at least one terminal device accesses a network through a first device;
• send first request information, wherein the first request information notifies a first mobility management network element to perform path handover on the at least one terminal device, and the first mobility management network element serves the at least one terminal device, wherein the first request information comprises at least one first request message, and the at least one first request message is in one-to-one correspondence with the at least one terminal device;
• obtain first device identification information, wherein the first device identification information identifies the first device;
• determine a same first mobility management network element for each of the at least one terminal device based on the first device identification information;
• and
• store a correspondence between the first device identification information, identification information of the at least one terminal device, and identification information of the first mobility management network element, wherein sending the first request information comprises sending the first request information to the first mobility management network element based on the correspondence.