The invention relates to a method performed by a network function capable of supporting at least a user plane, UP, functional part of a base station (440B), comprises establishing a transport network layer, TNL, association with a control plane, CP, functional part of the base station; receiving a request message (501) from the CP functional part of the base station (415), wherein the request message comprises an identifier of the base station; creating a UP functional part of the base station using the identifier of the base station; and transmitting a response message (505) to the CP functional part of the base station, wherein the response message comprises an identifier of the created UP functional part of the base station; the invention further relates to a method performed by a CP functional part of a base station; and to corresponding network node adapted to perform above-described methods.