Session migration method and device applied to a UE tracking area update

An apparatus comprising:

• an interface;
• a processor;
• and
• a non-transitory computer-readable storage medium storing a program to be executed by the processor, the program including instructions to:
• create a first session between a terminal device and a source session management function entity, wherein a service area of the source session management function entity comprises a first tracking area (TA);
• sending a first request message to a target mobility management function (MMF) entity;
• after the terminal device moves from the first TA to a second TA, receiving, from the target (MMF) entity, a second response message that carries instruction information;
• and
• send information used to trigger creation of a second session to the target MMF entity according to instruction information obtained by an obtaining unit, wherein the second session is a session between a target session management function entity and the terminal device, and both a service area of the target MMF entity and a service area of the target session management function entity comprise the second TA.

A non-transitory computer-readable medium storing computer instructions for execution by one or more processors, wherein the computer instructions instruct the one or more processors to perform operations comprising:

• creating a first session between a terminal device and a source session management function entity, wherein a service area of the source session management function entity comprises a first tracking area (TA);
• sending a first request message to a target mobility management function (MMF) entity;
• after moving from the first TA to a second TA, receiving, from the target (MMF) entity, a second response message that carries instruction information;
• and
• sending information used to trigger creation of a second session to the target (MMF) entity according to the instruction information, wherein the second session is a session between a target session management function entity and the terminal device, and both a service area of the target (MMF) entity and a service area of the target session management function entity comprise the second TA.