Method and apparatus for session management function reselection

A method performed by a second session management function (SMF), the method comprising:

• receiving a create session management context request comprising a reason of selecting the second SMF to serve a session of a user equipment (UE) from an access and mobility function, the session of the UE being currently served by a first SMF and an access network, the reason indicating that the session of the UE is still served by the access network;
• sending a session context request comprising the reason of selecting the second SMF to serve the session of the UE to the first SMF;
• receiving a session context response comprising the session management context of the session of the UE and tunnel information of the access network from the first SMF;
• and
• sending a create session management context response comprising a session resource modify request to the access and mobility function, the session resource modify request comprising the access network tunnel information of the access network received from the first SMF.

An access and mobility function, comprising:

• a processor;
• and
• a memory coupled to the processor, the memory containing instructions executable by the processor, whereby the access and mobility function is operative to:
• select a second session management function (SMF) to serve a session of a user equipment (UE), the session of the UE being currently served by a first SMF and an access network;
• send a create session management context request comprising a reason of selecting the second SMF to serve the session of the UE to the second SMF, the reason indicating that the session of the UE is still served by the access network;
• receive a create session management context response comprising a session resource modify request from the second SMF, the session resource modify request comprising access network tunnel information of the access network;
• and
• send the session resource modify request to the access network.

A second session management function (SMF), comprising:

• a processor;
• and
• a memory coupled to the processor, the memory containing instructions executable by the processor, whereby the second SMF is operative to:
• receive a create session management context request comprising a reason of selecting the second SMF to serve a session of a user equipment (UE) from an access and mobility function, the session of the UE being currently served by a first SMF and an access network, the reason indicating that the session of the UE is still served by the access network;
• send a session context request comprising the reason of selecting the second SMF to serve the session of the UE to the first SMF;
• receive a session context response comprising the session management context of the session of the UE and tunnel information of the access network from the first SMF;
• and
• send a create session management context response comprising a session resource modify request to the access and mobility function, the session resource modify request comprises comprising access network tunnel information of the access network received from the first SMF.