A source eNB determines whether an X2 interface is established between the source eNB and a target eNB when the source eNB performs a handover of a UE under the control of the source eNB to the target eNB. When the X2 interface is not established between the source eNB and the target eNB, the source eNB inquires with an address management node about the IP address of the target eNB. Upon receipt of the IP address of the target eNB from the address management node, the source eNB accesses the target eNB using the IP address and establishes the X2 interface. After establishing the X2 interface, the source eNB performs a handover of the UE to the target eNB.