Core network and base station

A base station, comprising:

• a transmission and reception unit that receives a data flow from a base station of a handover source and a core network and starts to transmit the data flow transmitted from the core network to a user equipment when an end marker of the data flow transmitted from the base station of the handover source is received;
• and
• an end marker detecting unit that detects the end marker of the data flow transferred from the base station of the handover source,
• wherein the transmission and reception unit receives the data flow having a flow identifier and a flow priority from the base station of the handover source via a tunnel, and
• when the end marker detecting unit detects the end marker generated in accordance with a generation rule based on one or more of the flow identifier, the flow priority, and the tunnel, the transmission and reception unit starts to transmit the data flow corresponding to the detected end marker which is received from the core network.