Operating system, core network, mobile communication system, method, and program

A method comprising:

• obtaining identification information of a first terminal apparatus managed by a first mobile communication operator, and identification information of a second terminal apparatus managed by a second mobile communication operator different from the first mobile communication operator;
• and
• transmitting, to a core network node managing a terminal apparatus connected to a core network in a mobile communication system, the identification information of the first terminal apparatus and the identification information of the second terminal apparatus.

(canceled)

A core network of a mobile communication system, the core network comprising:

• a first node, including a memory storing instructions and one or more processors configured to execute the instructions, configured to store pieces of identification information of a plurality of respective terminal apparatuses managed by a plurality of different mobile communication operators;
• and
• a second node, including a memory storing instructions and one or more processors configured to execute the instructions, configured to authenticate a terminal apparatus to be connected to the core network, based on the pieces of identification information stored in the first node.

18-19. (canceled)