The UE and the corresponding method of a dual connectivity 3GPP (3rd Generation Partnership Project) compatible with the mobile communication network user equipment (UE) in the supporting is disclosed. Method, the master is connected to the downlink (DL) master eNB (MeNB) data or received from the serving cells only the secondary cell group (SCG) is connected to the secondary eNB (SeNB) through SCG DRB, through the SCG and, also split DRB of the DRB (Data Radio Bearer) type that is received from the serving cell of the cell groups (MCG), or a step of detecting a signaling reset process of changing the DRB DRB type. Hand-over, when the DRB reset process types, including SCG change and one or more of the DRB-type change detection method is based on the initial DRB set, the final DRB settings and related DRB reset process, type of one or more of the requirements resulting from the DRB reset determining an associated operating layer 2 DRB; And performing an operation related to the determined layer 2 DRB.