This invention flexibly controls the number of user planes in a communication system. In a communication system, a base station is in a local area network and at least one user plane function arranged in a cloud are connected. A determination is made as to whether or not a new user plane function should be added, taking into consideration: the traffic amount, from the maximum traffic amount using the local area network, of user data transferred by the at least one user plane function using the local area network; and an anticipated traffic amount of a new user plane function.