Provided is a system, comprising: a control plane device; and a plurality of user plane devices, wherein the control plane device including: a request receiving unit for receiving a session generating request transmitted by a mobility management device, which has received a connection request from a user terminal; a user plane device selection unit for selecting a user plane device corresponding to the user terminal from the plurality of user plane devices, based on the session generating request; an address acquiring unit for obtaining an IP address assigned to the user terminal based on the session generating request; and a response transmission unit for transmitting a session generating response including the IP address assigned to the user terminal, identification information and IP address of the user plane device selected by the user plane device selection unit, and IP address of a PGW-U.